diff --git a/.github/workflows/next.yml b/.github/workflows/next.yml
index e0dd8feeec..07250449e3 100644
--- a/.github/workflows/next.yml
+++ b/.github/workflows/next.yml
@@ -20,7 +20,3 @@ jobs:
       upload: true
       next: ${{ github.ref_name }}
     secrets: inherit
-
-  docker:
-    uses: ./.github/workflows/docker-shared.yml
-    secrets: inherit
diff --git a/.gitignore b/.gitignore
index 251a0d7f0f..da5bf8e6c8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,7 @@
+# IDEs.
+/.vscode
+/.idea
+
 # Bazel.
 /.user.bazelrc
 /bazel-*
diff --git a/VERSION b/VERSION
index 3e162f02ea..9f55b2ccb5 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.12
+3.0
diff --git a/pkg/c3/defs.h b/pkg/c3/defs.h
index 38b39263a9..bbf8d91ef7 100644
--- a/pkg/c3/defs.h
+++ b/pkg/c3/defs.h
@@ -149,6 +149,8 @@
         mkdir(a, b);})
 #     define c3_rmdir(a) ({                                     \
         rmdir(a);})
+#     define c3_link(a, b) ({                                   \
+        link(a, b);})
 #     define c3_unlink(a) ({                                    \
         unlink(a);})
 #     define c3_fopen(a, b) ({                                  \
diff --git a/pkg/noun/BUILD.bazel b/pkg/noun/BUILD.bazel
index 964e4bf60f..1949a7d878 100644
--- a/pkg/noun/BUILD.bazel
+++ b/pkg/noun/BUILD.bazel
@@ -8,9 +8,8 @@ vere_library(
     name = "noun",
     srcs = glob(
         [
-            "*.c",
-            "*.h",
-            "jets/tree.c",
+            "**/*.c",
+            "**/*.h",
             "jets/*.h",
             "jets/**/*.c",
         ],
diff --git a/pkg/noun/allocate.c b/pkg/noun/allocate.c
index ace4473a4a..b905ce5912 100644
--- a/pkg/noun/allocate.c
+++ b/pkg/noun/allocate.c
@@ -16,15 +16,6 @@ u3_road* u3a_Road;
 c3_w u3_Code;
 #endif
 
-//  declarations of inline functions
-//
-
-void u3a_config_loom(c3_w ver_w);
-void *u3a_into(c3_w x);
-c3_w u3a_outa(void *p);
-c3_w u3a_to_off(c3_w som);
-void *u3a_to_ptr(c3_w som);
-c3_w *u3a_to_wtr(c3_w som);
 c3_w u3a_to_pug(c3_w off);
 c3_w u3a_to_pom(c3_w off);
 
@@ -67,12 +58,12 @@ _box_count(c3_ws siz_ws) { }
    _box_count, (others?) should have perhaps its own header and certainly its
    own prefix. having to remind yourself that _box_count doesn't actually do
    anything unless U3_CPU_DEBUG is defined is annoying. */
-#define _box_vaal(box_u)                                                \
-  do {                                                                  \
-    c3_dessert(((uintptr_t)u3a_boxto(box_u)                             \
-                & u3C.balign_d-1) == 0);                                \
-    c3_dessert((((u3a_box*)(box_u))->siz_w                              \
-                & u3C.walign_w-1) == 0);                                \
+#define _box_vaal(box_u)                                        \
+  do {                                                          \
+  c3_dessert(((uintptr_t)u3a_boxto(box_u)                       \
+              & u3a_balign-1) == 0);                            \
+  c3_dessert((((u3a_box*)(box_u))->siz_w                        \
+              & u3a_walign-1) == 0);                            \
   } while(0)
 
 /* _box_slot(): select the right free list to search for a block.
@@ -302,7 +293,7 @@ _ca_box_make_hat(c3_w len_w, c3_w ald_w, c3_w off_w, c3_w use_w)
     all_p += c3_wiseof(u3a_box) + off_w;
     pad_w = c3_align(all_p, ald_w, C3_ALGHI)
       - all_p;
-    siz_w = c3_align(len_w + pad_w, u3C.walign_w, C3_ALGHI);
+    siz_w = c3_align(len_w + pad_w, u3a_walign, C3_ALGHI);
 
     //  hand-inlined: siz_w >= u3a_open(u3R)
     //
@@ -316,7 +307,7 @@ _ca_box_make_hat(c3_w len_w, c3_w ald_w, c3_w off_w, c3_w use_w)
     all_p += c3_wiseof(u3a_box) + off_w;
     pad_w = all_p
       - c3_align(all_p, ald_w, C3_ALGLO);
-    siz_w = c3_align(len_w + pad_w, u3C.walign_w, C3_ALGHI);
+    siz_w = c3_align(len_w + pad_w, u3a_walign, C3_ALGHI);
 
     //  hand-inlined: siz_w >= u3a_open(u3R)
     //
@@ -508,7 +499,7 @@ _ca_willoc(c3_w len_w, c3_w ald_w, c3_w off_w)
         box_p = all_p = *pfr_p;
         all_p += c3_wiseof(u3a_box) + off_w;
         c3_w pad_w = c3_align(all_p, ald_w, C3_ALGHI) - all_p;
-        c3_w des_w = c3_align(siz_w + pad_w, u3C.walign_w, C3_ALGHI);
+        c3_w des_w = c3_align(siz_w + pad_w, u3a_walign, C3_ALGHI);
 
         /* calls maximally requesting DWORD alignment of returned pointer
            shouldn't require padding. */
@@ -711,17 +702,17 @@ u3a_wtrim(void* tox_v, c3_w old_w, c3_w len_w)
     c3_w*    box_w = (void*)u3a_botox(nov_w);
 
     c3_w* end_w = c3_align(nov_w + len_w + 1, /* +1 for trailing allocation size */
-                           u3C.balign_d,
+                           u3a_balign,
                            C3_ALGHI);
 
     c3_w  asz_w = (end_w - box_w);      /* total size in words of new allocation */
     if (box_u->siz_w <= asz_w) return;
     c3_w  bsz_w = box_u->siz_w - asz_w; /* size diff in words between old and new */
 
-    c3_dessert(asz_w && ((asz_w & u3C.walign_w-1) == 0)); /* new allocation size must be non-zero and DWORD multiple */
+    c3_dessert(asz_w && ((asz_w & u3a_walign-1) == 0)); /* new allocation size must be non-zero and DWORD multiple */
     c3_dessert(end_w < (box_w + box_u->siz_w));         /* desired alloc end must not exceed existing boundaries */
-    c3_dessert(((uintptr_t)end_w & u3C.balign_d-1) == 0); /* address of box getting freed must be DWORD aligned */
-    c3_dessert((bsz_w & u3C.walign_w-1) == 0);            /* size of box getting freed must be DWORD multiple */
+    c3_dessert(((uintptr_t)end_w & u3a_balign-1) == 0); /* address of box getting freed must be DWORD aligned */
+    c3_dessert((bsz_w & u3a_walign-1) == 0);            /* size of box getting freed must be DWORD multiple */
 
     _box_attach(_box_make(end_w, bsz_w, 0)); /* free the unneeded space */
 
@@ -1747,24 +1738,12 @@ u3a_rewritten_noun(u3_noun som)
     return som;
   }
   u3_post som_p = u3a_rewritten(u3a_to_off(som));
-
-  /* If this is being called during a migration, one-bit pointer compression
-     needs to be temporarily enabled so the rewritten reference is compressed */
-  if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
-    u3C.vits_w = 1;
-
   if ( c3y == u3a_is_pug(som) ) {
-    som_p = u3a_to_pug(som_p);
+    return u3a_to_pug(som_p);
   }
   else {
-    som_p = u3a_to_pom(som_p);
+    return u3a_to_pom(som_p);
   }
-
-  /* likewise, pointer compression is disabled until migration is complete */
-  if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
-    u3C.vits_w = 0;
-
-  return som_p;
 }
 
 /* u3a_mark_mptr(): mark a malloc-allocated ptr for gc.
@@ -2152,7 +2131,8 @@ u3a_mark_road(FILE* fil_u)
   tot_w += u3a_maid(fil_u, "  profile batteries", u3a_mark_noun(u3R->pro.don));
   tot_w += u3a_maid(fil_u, "  profile doss", u3a_mark_noun(u3R->pro.day));
   tot_w += u3a_maid(fil_u, "  new profile trace", u3a_mark_noun(u3R->pro.trace));
-  tot_w += u3a_maid(fil_u, "  memoization cache", u3h_mark(u3R->cax.har_p));
+  tot_w += u3a_maid(fil_u, "  transient memoization cache", u3h_mark(u3R->cax.har_p));
+  tot_w += u3a_maid(fil_u, "  persistent memoization cache", u3h_mark(u3R->cax.per_p));
   return   u3a_maid(fil_u, "total road stuff", tot_w);
 }
 
@@ -2179,6 +2159,7 @@ u3a_rewrite_compact(void)
   u3a_rewrite_noun(u3R->pro.day);
   u3a_rewrite_noun(u3R->pro.trace);
   u3h_rewrite(u3R->cax.har_p);
+  u3h_rewrite(u3R->cax.per_p);
 
   u3R->ski.gul = u3a_rewritten_noun(u3R->ski.gul);
   u3R->bug.tax = u3a_rewritten_noun(u3R->bug.tax);
@@ -2187,6 +2168,7 @@ u3a_rewrite_compact(void)
   u3R->pro.day = u3a_rewritten_noun(u3R->pro.day);
   u3R->pro.trace = u3a_rewritten_noun(u3R->pro.trace);
   u3R->cax.har_p = u3a_rewritten(u3R->cax.har_p);
+  u3R->cax.per_p = u3a_rewritten(u3R->cax.per_p);
 }
 
 /* _ca_print_box(): heuristically print the contents of an allocation box.
diff --git a/pkg/noun/allocate.h b/pkg/noun/allocate.h
index 7355954abd..6081b96e7d 100644
--- a/pkg/noun/allocate.h
+++ b/pkg/noun/allocate.h
@@ -3,7 +3,6 @@
 
 #include "error.h"
 #include "manage.h"
-#include "options.h"
 
   /**  Constants.
   **/
@@ -11,14 +10,21 @@
     */
 #     define u3a_bits    U3_OS_LoomBits /* 30 */
 
-    /* u3a_vits_max: number of virtual bits in a reference gained via pointer
-       compression
+    /* u3a_vits: number of virtual bits in a noun reference gained via shifting
     */
-#     define u3a_vits_max 1
+#     define u3a_vits    1
+
+    /* u3a_walign: references into the loom are guaranteed to be word-aligned to:
+    */
+#     define u3a_walign  (1 << u3a_vits)
+
+    /* u3a_balign: u3a_walign in bytes
+    */
+#     define u3a_balign  (sizeof(c3_w)*u3a_walign)
 
      /* u3a_bits_max: max loom bex
      */
-#    define u3a_bits_max (8 * sizeof(c3_w) + u3a_vits_max)
+#    define u3a_bits_max (8 * sizeof(c3_w) + u3a_vits)
 
     /* u3a_page: number of bits in word-addressed page.  12 == 16K page
     */
@@ -26,11 +32,11 @@
 
     /* u3a_pages: maximum number of pages in memory.
     */
-#     define u3a_pages   (1ULL << (u3a_bits + u3a_vits_max - u3a_page) )
+#     define u3a_pages   (1ULL << (u3a_bits + u3a_vits - u3a_page) )
 
     /* u3a_words: maximum number of words in memory.
     */
-#     define u3a_words   ( 1ULL << (u3a_bits + u3a_vits_max ))
+#     define u3a_words   ( 1ULL << (u3a_bits + u3a_vits))
 
     /* u3a_bytes: maximum number of bytes in memory.
     */
@@ -148,11 +154,11 @@
 
         u3a_jets jed;                         //  jet dashboard
 
-        struct {                              // bytecode state
-          u3p(u3h_root) har_p;                // formula->post of bytecode
+        struct {                              //  bytecode state
+          u3p(u3h_root) har_p;                //  formula->post of bytecode
         } byc;
 
-        struct {                              //  namespace
+        struct {                              //  scry namespace
           u3_noun gul;                        //  (list $+(* (unit (unit)))) now
         } ski;
 
@@ -169,8 +175,9 @@
           u3_noun day;                        //  doss, only in u3H (moveme)
         } pro;
 
-        struct {                              //  memoization
-          u3p(u3h_root) har_p;                //  (map (pair term noun) noun)
+        struct {                              //  memoization caches
+          u3p(u3h_root) har_p;                //  transient
+          u3p(u3h_root) per_p;                //  persistent
         } cax;
       } u3a_road;
       typedef u3a_road u3_road;
@@ -226,7 +233,7 @@
     /* u3a_is_atom(): yes if noun [som] is direct atom or indirect atom.
     */
 #     define u3a_is_atom(som)    c3o(u3a_is_cat(som), \
-                                         u3a_is_pug(som))
+                                     u3a_is_pug(som))
 #     define u3ud(som)           u3a_is_atom(som)
 
     /* u3a_is_cell: yes if noun [som] is cell.
@@ -355,7 +362,7 @@
 #     define _rod_vaal(rod_u)                                           \
              do {                                                       \
                c3_dessert(((uintptr_t)((u3a_road*)(rod_u))->hat_p       \
-                           & u3C.walign_w-1) == 0);                     \
+                           & u3a_walign-1) == 0);                     \
              } while(0)
 
 
@@ -374,68 +381,40 @@
 
 #   define u3_Loom      ((c3_w *)(void *)U3_OS_LoomBase)
 
-  /**  inline functions.
-  **/
-  /* u3a_config_loom(): configure loom information by u3v version
-   */
-  inline void u3a_config_loom(c3_w ver_w) {
-    switch (ver_w) {
-    case U3V_VER1:
-      u3C.vits_w = 0;
-      break;
-    case U3V_VER2:
-      u3C.vits_w = 1;
-      break;
-    default:
-      u3_assert(0);
-    }
-
-  u3C.walign_w = 1 << u3C.vits_w;
-  u3C.balign_d = sizeof(c3_w) * u3C.walign_w;
-}
-
   /* u3a_into(): convert loom offset [x] into generic pointer.
    */
-  inline void *u3a_into(c3_w x) {
-    return u3_Loom + x;
-  }
+#   define u3a_into(x)  ((void *)(u3_Loom + (x)))
 
   /* u3a_outa(): convert pointer [p] into word offset into loom.
    */
-  inline c3_w u3a_outa(void *p) {
-    return ((c3_w *)p) - u3_Loom;
-  }
+#   define u3a_outa(p)  ((c3_w *)(void *)(p) - u3_Loom)
 
   /* u3a_to_off(): mask off bits 30 and 31 from noun [som].
    */
-  inline c3_w u3a_to_off(c3_w som) {
-    return (som & 0x3fffffff) << u3C.vits_w;
-  }
+#   define u3a_to_off(som)  (((som) & 0x3fffffff) << u3a_vits)
 
   /* u3a_to_ptr(): convert noun [som] into generic pointer into loom.
    */
-  inline void *u3a_to_ptr(c3_w som) {
-    return u3a_into(u3a_to_off(som));
-  }
+#   define u3a_to_ptr(som)  (u3a_into(u3a_to_off(som)))
 
   /* u3a_to_wtr(): convert noun [som] into word pointer into loom.
    */
-  inline c3_w *u3a_to_wtr(c3_w som) {
-    return (c3_w *)u3a_to_ptr(som);
-  }
+#   define u3a_to_wtr(som)  ((c3_w *)u3a_to_ptr(som))
 
+  /**  Inline functions.
+  **/
   /* u3a_to_pug(): set bit 31 of [off].
    */
   inline c3_w u3a_to_pug(c3_w off) {
-    c3_dessert((off & u3C.walign_w-1) == 0);
-    return (off >> u3C.vits_w) | 0x80000000;
+    c3_dessert((off & u3a_walign-1) == 0);
+    return (off >> u3a_vits) | 0x80000000;
   }
 
   /* u3a_to_pom(): set bits 30 and 31 of [off].
    */
   inline c3_w u3a_to_pom(c3_w off) {
-    c3_dessert((off & u3C.walign_w-1) == 0);
-    return (off >> u3C.vits_w) | 0xc0000000;
+    c3_dessert((off & u3a_walign-1) == 0);
+    return (off >> u3a_vits) | 0xc0000000;
   }
 
     /**  road stack.
diff --git a/pkg/noun/events.c b/pkg/noun/events.c
index dc1ba965d0..d4f6c92ed0 100644
--- a/pkg/noun/events.c
+++ b/pkg/noun/events.c
@@ -398,23 +398,14 @@ _ce_ephemeral_open(c3_i* eph_i)
 /* _ce_image_open(): open or create image.
 */
 static c3_o
-_ce_image_open(u3e_image* img_u)
+_ce_image_open(u3e_image* img_u, c3_c* ful_c)
 {
   c3_i mod_i = O_RDWR | O_CREAT;
-  c3_c ful_c[8193];
-
-  snprintf(ful_c, 8192, "%s", u3P.dir_c);
-  c3_mkdir(ful_c, 0700);
-
-  snprintf(ful_c, 8192, "%s/.urb", u3P.dir_c);
-  c3_mkdir(ful_c, 0700);
-
-  snprintf(ful_c, 8192, "%s/.urb/chk", u3P.dir_c);
-  c3_mkdir(ful_c, 0700);
 
-  snprintf(ful_c, 8192, "%s/.urb/chk/%s.bin", u3P.dir_c, img_u->nam_c);
-  if ( -1 == (img_u->fid_i = c3_open(ful_c, mod_i, 0666)) ) {
-    fprintf(stderr, "loom: c3_open %s: %s\r\n", ful_c, strerror(errno));
+  c3_c pax_c[8192];
+  snprintf(pax_c, 8192, "%s/%s.bin", ful_c, img_u->nam_c);
+  if ( -1 == (img_u->fid_i = c3_open(pax_c, mod_i, 0666)) ) {
+    fprintf(stderr, "loom: c3_open %s: %s\r\n", pax_c, strerror(errno));
     return c3n;
   }
   else if ( c3n == _ce_image_stat(img_u, &img_u->pgs_w) ) {
@@ -787,14 +778,16 @@ _ce_patch_sync(u3_ce_patch* pat_u)
 
 /* _ce_image_sync(): make sure image is synced to disk.
 */
-static void
+static c3_o
 _ce_image_sync(u3e_image* img_u)
 {
   if ( -1 == c3_sync(img_u->fid_i) ) {
     fprintf(stderr, "loom: image (%s) sync failed: %s\r\n",
                     img_u->nam_c, strerror(errno));
-    u3_assert(!"loom: image sync");
+    return c3n;
   }
+
+  return c3y;
 }
 
 /* _ce_image_resize(): resize image, truncating if it shrunk.
@@ -1345,54 +1338,77 @@ _ce_image_copy(u3e_image* fom_u, u3e_image* tou_u)
   return c3y;
 }
 
-/* u3e_backup(): copy snapshot to .urb/bhk (if it doesn't exist yet).
+/* u3e_backup(): copy snapshot from [pux_c] to [pax_c],
+ * overwriting optionally. note that image files must
+ * be named "north" and "south".
 */
 c3_o
-u3e_backup(c3_o ovw_o)
+u3e_backup(c3_c* pux_c, c3_c* pax_c, c3_o ovw_o)
 {
-  u3e_image nop_u = { .nam_c = "north", .pgs_w = 0 };
-  u3e_image sop_u = { .nam_c = "south", .pgs_w = 0 };
-  c3_i mod_i = O_RDWR | O_CREAT; // XX O_TRUNC ?
-  c3_c ful_c[8193];
+  //  source image files from [pux_c]
+  u3e_image nux_u = { .nam_c = "north", .pgs_w = 0 };
+  u3e_image sux_u = { .nam_c = "south", .pgs_w = 0 };
+
+  //  destination image files to [pax_c]
+  u3e_image nax_u = { .nam_c = "north", .pgs_w = 0 };
+  u3e_image sax_u = { .nam_c = "south", .pgs_w = 0 };
 
-  snprintf(ful_c, 8192, "%s/.urb/bhk", u3P.dir_c);
+  c3_i mod_i = O_RDWR | O_CREAT;
+
+  if ( !pux_c || !pax_c ) {
+    fprintf(stderr, "loom: image backup: bad path\r\n");
+    return c3n;
+  }
 
-  if ( (c3n == ovw_o) && c3_mkdir(ful_c, 0700) ) {
+  if ( (c3n == ovw_o) && c3_mkdir(pax_c, 0700) ) {
     if ( EEXIST != errno ) {
       fprintf(stderr, "loom: image backup: %s\r\n", strerror(errno));
     }
     return c3n;
   }
 
-  snprintf(ful_c, 8192, "%s/.urb/bhk/%s.bin", u3P.dir_c, nop_u.nam_c);
-
-  if ( -1 == (nop_u.fid_i = c3_open(ful_c, mod_i, 0666)) ) {
-    fprintf(stderr, "loom: c3_open %s: %s\r\n", ful_c, strerror(errno));
+  //  open source image files if they exist
+  //
+  c3_c nux_c[8193];
+  snprintf(nux_c, 8192, "%s/%s.bin", pux_c, nux_u.nam_c);
+  if ( (0 != access(nux_c, F_OK)) || (c3n == _ce_image_open(&nux_u, pux_c)) ) {
+    fprintf(stderr, "loom: couldn't open north image at %s\r\n", pux_c);
+    return c3n;
+  }
+  c3_c sux_c[8193];
+  snprintf(sux_c, 8192, "%s/%s.bin", pux_c, sux_u.nam_c);
+  if ( (0 != access(sux_c, F_OK)) || (c3n == _ce_image_open(&sux_u, pux_c)) ) {
+    fprintf(stderr, "loom: couldn't open south image at %s\r\n", pux_c);
     return c3n;
   }
 
-  snprintf(ful_c, 8192, "%s/.urb/bhk/%s.bin", u3P.dir_c, sop_u.nam_c);
-
-  if ( -1 == (sop_u.fid_i = c3_open(ful_c, mod_i, 0666)) ) {
-    fprintf(stderr, "loom: c3_open %s: %s\r\n", ful_c, strerror(errno));
+  //  open destination image files
+  c3_c nax_c[8193];
+  snprintf(nax_c, 8192, "%s/%s.bin", pax_c, nax_u.nam_c);
+  if ( -1 == (nax_u.fid_i = c3_open(nax_c, mod_i, 0666)) ) {
+    fprintf(stderr, "loom: c3_open %s: %s\r\n", nax_c, strerror(errno));
+    return c3n;
+  }
+  c3_c sax_c[8193];
+  snprintf(sax_c, 8192, "%s/%s.bin", pax_c, sax_u.nam_c);
+  if ( -1 == (sax_u.fid_i = c3_open(sax_c, mod_i, 0666)) ) {
+    fprintf(stderr, "loom: c3_open %s: %s\r\n", sax_c, strerror(errno));
     return c3n;
   }
 
-  if (  (c3n == _ce_image_copy(&u3P.nor_u, &nop_u))
-     || (c3n == _ce_image_copy(&u3P.sou_u, &sop_u)) )
+  if (  (c3n == _ce_image_copy(&nux_u, &nax_u))
+     || (c3n == _ce_image_copy(&sux_u, &sax_u))
+     || (c3n == _ce_image_sync(&nax_u))
+     || (c3n == _ce_image_sync(&sax_u)) )
   {
-
-    c3_unlink(ful_c);
-    snprintf(ful_c, 8192, "%s/.urb/bhk/%s.bin", u3P.dir_c, nop_u.nam_c);
-    c3_unlink(ful_c);
-    snprintf(ful_c, 8192, "%s/.urb/bhk", u3P.dir_c);
-    c3_rmdir(ful_c);
+    c3_unlink(nax_c);
+    c3_unlink(sax_c);
     fprintf(stderr, "loom: image backup failed\r\n");
     return c3n;
   }
 
-  close(nop_u.fid_i);
-  close(sop_u.fid_i);
+  close(nax_u.fid_i);
+  close(sax_u.fid_i);
   fprintf(stderr, "loom: image backup complete\r\n");
   return c3y;
 }
@@ -1462,8 +1478,9 @@ u3e_save(u3_post low_p, u3_post hig_p)
 
   _ce_patch_apply(pat_u);
 
-  _ce_image_sync(&u3P.nor_u);
-  _ce_image_sync(&u3P.sou_u);
+  u3_assert( c3y == _ce_image_sync(&u3P.nor_u) );
+  u3_assert( c3y == _ce_image_sync(&u3P.sou_u) );
+
   _ce_patch_free(pat_u);
   _ce_patch_delete();
 
@@ -1502,8 +1519,6 @@ u3e_save(u3_post low_p, u3_post hig_p)
   }
 
   u3e_toss(low_p, hig_p);
-
-  u3e_backup(c3n);
 }
 
 /* _ce_toss_pages(): discard ephemeral pages.
@@ -1573,8 +1588,10 @@ u3e_live(c3_o nuu_o, c3_c* dir_c)
 
     //  Open image files.
     //
-    if ( (c3n == _ce_image_open(&u3P.nor_u)) ||
-         (c3n == _ce_image_open(&u3P.sou_u)) )
+    c3_c chk_c[8193];
+    snprintf(chk_c, 8193, "%s/.urb/chk", u3P.dir_c);
+    if ( (c3n == _ce_image_open(&u3P.nor_u, chk_c)) ||
+         (c3n == _ce_image_open(&u3P.sou_u, chk_c)) )
     {
       fprintf(stderr, "boot: image failed\r\n");
       exit(1);
@@ -1587,8 +1604,8 @@ u3e_live(c3_o nuu_o, c3_c* dir_c)
       */
       if ( 0 != (pat_u = _ce_patch_open()) ) {
         _ce_patch_apply(pat_u);
-        _ce_image_sync(&u3P.nor_u);
-        _ce_image_sync(&u3P.sou_u);
+        u3_assert( c3y == _ce_image_sync(&u3P.nor_u) );
+        u3_assert( c3y == _ce_image_sync(&u3P.sou_u) );
         _ce_patch_free(pat_u);
         _ce_patch_delete();
       }
@@ -1659,6 +1676,9 @@ u3e_stop(void)
     close(u3P.eph_i);
     unlink(u3C.eph_c);
   }
+
+  close(u3P.sou_u.fid_i);
+  close(u3P.sou_u.fid_i);
 }
 
 /* u3e_yolo(): disable dirty page tracking, read/write whole loom.
@@ -1698,6 +1718,8 @@ u3e_init(void)
 {
   u3P.pag_w = u3C.wor_i >> u3a_page;
 
+  u3P.nor_u.fid_i = u3P.sou_u.fid_i = -1;
+
   u3e_foul();
 
 #ifdef U3_GUARD_PAGE
diff --git a/pkg/noun/events.h b/pkg/noun/events.h
index b17dcba65d..7442c9df94 100644
--- a/pkg/noun/events.h
+++ b/pkg/noun/events.h
@@ -74,10 +74,11 @@
 
   /** Functions.
   **/
-    /* u3e_backup(): copy the snapshot from chk to bhk. 
+    /* u3e_backup(): copy the snapshot from [pux_c] to [pax_c],
+     * overwriting optional.
     */
-      c3_o 
-      u3e_backup(c3_o ovw_o);
+      c3_o
+      u3e_backup(c3_c* pux_c, c3_c* pax_c, c3_o ovw_o);
 
     /* u3e_fault(): handle a memory fault.
     */
diff --git a/pkg/noun/hashtable.c b/pkg/noun/hashtable.c
index f4b1201db4..a21352bf82 100644
--- a/pkg/noun/hashtable.c
+++ b/pkg/noun/hashtable.c
@@ -1042,15 +1042,8 @@ _ch_rewrite_node(u3h_node* han_u, c3_w lef_w)
     else {
       void* hav_v = u3h_slot_to_node(sot_w);
       u3h_node* nod_u = u3to(u3h_node,u3a_rewritten(u3of(u3h_node,hav_v)));
-
-      if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
-        u3C.vits_w = 1;
-
       han_u->sot_w[i_w] = u3h_node_to_slot(nod_u);
 
-      if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
-        u3C.vits_w = 0;
-
       if ( 0 == lef_w ) {
         _ch_rewrite_buck(hav_v);
       } else {
@@ -1082,15 +1075,8 @@ u3h_rewrite(u3p(u3h_root) har_p)
     else if ( _(u3h_slot_is_node(sot_w)) ) {
       u3h_node* han_u = u3h_slot_to_node(sot_w);
       u3h_node* nod_u = u3to(u3h_node,u3a_rewritten(u3of(u3h_node,han_u)));
-
-      if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
-        u3C.vits_w = 1;
-
       har_u->sot_w[i_w] = u3h_node_to_slot(nod_u);
 
-      if (u3C.migration_state == MIG_REWRITE_COMPRESSED)
-        u3C.vits_w = 0;
-
       _ch_rewrite_node(han_u, 25);
     }
   }
diff --git a/pkg/noun/hashtable.h b/pkg/noun/hashtable.h
index 2558516dca..69ba962dd9 100644
--- a/pkg/noun/hashtable.h
+++ b/pkg/noun/hashtable.h
@@ -16,9 +16,8 @@
     ***  corresponding to the 32-slot nodes for everything under
     ***  the root node.
     ***
-    ***  We store an extra "freshly warm" bit for a simple
-    ***  clock-algorithm reclamation policy, not yet implemented.
-    ***  Search "clock algorithm" to figure it out.
+    ***  We store an extra "freshly warm" bit and use it for a simple
+    ***  clock-algorithm reclamation policy.
     **/
       /* u3h_slot: map slot.
       **
@@ -79,8 +78,8 @@
 #     define  u3h_slot_is_node(sot)  ((1 == ((sot) >> 30)) ? c3y : c3n)
 #     define  u3h_slot_is_noun(sot)  ((1 == ((sot) >> 31)) ? c3y : c3n)
 #     define  u3h_slot_is_warm(sot)  (((sot) & 0x40000000) ? c3y : c3n)
-#     define  u3h_slot_to_node(sot)  (u3a_into(((sot) & 0x3fffffff) << u3C.vits_w))
-#     define  u3h_node_to_slot(ptr)  ((u3a_outa((ptr)) >> u3C.vits_w) | 0x40000000)
+#     define  u3h_slot_to_node(sot)  (u3a_into(((sot) & 0x3fffffff) << u3a_vits))
+#     define  u3h_node_to_slot(ptr)  ((u3a_outa((ptr)) >> u3a_vits) | 0x40000000)
 #     define  u3h_noun_be_warm(sot)  ((sot) | 0x40000000)
 #     define  u3h_noun_be_cold(sot)  ((sot) & ~0x40000000)
 #     define  u3h_slot_to_noun(sot)  (0x40000000 | (sot))
diff --git a/pkg/noun/jets.c b/pkg/noun/jets.c
index ea69021ccd..c69000afc7 100644
--- a/pkg/noun/jets.c
+++ b/pkg/noun/jets.c
@@ -18,15 +18,6 @@
 #include "vortex.h"
 #include "xtract.h"
 
-/**  Data structures.
-**/
-
-/* _cj_hank: cached hook information.
- */
-typedef struct {
-  u3_weak  hax;                     //  axis of hooked inner core
-  u3j_site sit_u;                   //  call-site data
-} _cj_hank;
 
 /**  Functions.
 **/
@@ -1069,7 +1060,7 @@ _cj_prog(u3_weak loc, u3_noun fol)
 /* cj_hank_find(): find cached hook information, keyed by arbitrary
  *                 prefix and term cords. RETAIN.
  */
-static _cj_hank*
+static u3j_hank*
 _cj_hank_find(u3_noun pre, u3_noun tam)
 {
   u3_noun key = u3nc(u3k(pre), u3k(tam));
@@ -1077,10 +1068,10 @@ _cj_hank_find(u3_noun pre, u3_noun tam)
 
   if ( u3_none != got ) {
     u3z(key);
-    return u3to(_cj_hank, got);
+    return u3to(u3j_hank, got);
   }
   else {
-    _cj_hank* new_u = u3a_walloc(c3_wiseof(_cj_hank));
+    u3j_hank* new_u = u3a_walloc(c3_wiseof(u3j_hank));
     u3a_road* rod_u = u3R;
 
     while ( rod_u->par_p && u3_none == got ) {
@@ -1092,7 +1083,7 @@ _cj_hank_find(u3_noun pre, u3_noun tam)
       new_u->hax = u3_none;
     }
     else {
-      _cj_hank* old_u = u3to(_cj_hank, got);
+      u3j_hank* old_u = u3to(u3j_hank, got);
       if ( u3_none != (new_u->hax = old_u->hax) ) {
         //  it's unusual but safe to "take" here, because
         //  u3a_take will no-op on senior nouns (just as u3k would)
@@ -1101,7 +1092,7 @@ _cj_hank_find(u3_noun pre, u3_noun tam)
       }
     }
 
-    u3h_put(u3R->jed.han_p, key, u3of(_cj_hank, new_u));
+    u3h_put(u3R->jed.han_p, key, u3of(u3j_hank, new_u));
     u3z(key);
     return new_u;
   }
@@ -1112,7 +1103,7 @@ _cj_hank_find(u3_noun pre, u3_noun tam)
  *                  core on return if valid. RETAIN.
  */
 static c3_o
-_cj_hank_fine(_cj_hank* han_u, u3_noun cor, u3_noun *inn)
+_cj_hank_fine(u3j_hank* han_u, u3_noun cor, u3_noun *inn)
 {
   u3_noun hax = han_u->hax;
   if ( u3_none == hax ) {
@@ -1134,7 +1125,7 @@ _cj_hank_fine(_cj_hank* han_u, u3_noun cor, u3_noun *inn)
 /* _cj_hank_lose(): release memory maintained in a hook cache.
 */
 static void
-_cj_hank_lose(_cj_hank* han_u)
+_cj_hank_lose(u3j_hank* han_u)
 {
   if ( u3_none != han_u->hax ) {
     u3z(han_u->hax);
@@ -1145,7 +1136,7 @@ _cj_hank_lose(_cj_hank* han_u)
 /* _cj_hank_fill(): slow path, populate han_u.
  */
 static u3_noun
-_cj_hank_fill(_cj_hank* han_u, u3_noun tam, u3_noun cor)
+_cj_hank_fill(u3j_hank* han_u, u3_noun tam, u3_noun cor)
 {
   u3_weak   loc, col;
   u3_noun   got, pat, nam, huc;
@@ -1642,7 +1633,7 @@ u3j_cook(const c3_c* key_c,
          const c3_c* tam_c)
 {
   u3_noun pro, key, tam, inn;
-  _cj_hank* han_u;
+  u3j_hank* han_u;
 
   u3t_on(glu_o);
   key = u3i_string(key_c);
@@ -1996,8 +1987,8 @@ static void
 _cj_reap_hank(u3_cell kev)
 {
   u3a_cell* kev_u = u3a_to_ptr(kev);
-  _cj_hank* nah_u = u3to(_cj_hank, kev_u->tel);
-  _cj_hank* han_u;
+  u3j_hank* nah_u = u3to(u3j_hank, kev_u->tel);
+  u3j_hank* han_u;
   u3_weak     got;
   u3_noun     key;
 
@@ -2013,7 +2004,7 @@ _cj_reap_hank(u3_cell kev)
   //  promote
   //
   if ( u3_none == got ) {
-    han_u      = u3a_walloc(c3_wiseof(_cj_hank));
+    han_u      = u3a_walloc(c3_wiseof(u3j_hank));
     han_u->hax = u3a_take(nah_u->hax);
     u3j_site_take(&(han_u->sit_u), &(nah_u->sit_u));
   }
@@ -2022,7 +2013,7 @@ _cj_reap_hank(u3_cell kev)
   else {
     u3_weak old;
 
-    han_u      = u3to(_cj_hank, got);
+    han_u      = u3to(u3j_hank, got);
     old        = han_u->hax;
     han_u->hax = u3a_take(nah_u->hax);
     u3j_site_take(&(nah_u->sit_u), &(nah_u->sit_u));
@@ -2033,7 +2024,7 @@ _cj_reap_hank(u3_cell kev)
     }
   }
 
-  u3h_put(u3R->jed.han_p, key, u3of(_cj_hank, han_u));
+  u3h_put(u3R->jed.han_p, key, u3of(u3j_hank, han_u));
   u3z(key);
 }
 
@@ -2141,7 +2132,7 @@ _cj_warm_tap(u3_noun kev, void* wit)
 static void
 _cj_ream_hank(u3_noun kev)
 {
-  u3j_site_ream(&(u3to(_cj_hank, u3t(kev))->sit_u));
+  u3j_site_ream(&(u3to(u3j_hank, u3t(kev))->sit_u));
 }
 
 /* u3j_ream(): rebuild warm state
@@ -2275,7 +2266,7 @@ static void
 _cj_mark_hank(u3_noun kev, void* dat)
 {
   c3_w* tot_w = (c3_w*) dat;
-  _cj_hank* han_u = u3to(_cj_hank, u3t(kev));
+  u3j_hank* han_u = u3to(u3j_hank, u3t(kev));
   *tot_w += u3a_mark_ptr(han_u);
   if ( u3_none != han_u->hax ) {
     *tot_w += u3a_mark_noun(han_u->hax);
@@ -2308,12 +2299,12 @@ u3j_mark(FILE* fil_u)
   return u3a_maid(fil_u, "total jet stuff", tot_w);
 }
 
-/* _cj_free_hank(): free an entry from the hank cache.
+/* u3j_free_hank(): free an entry from the hank cache.
 */
-static void
-_cj_free_hank(u3_noun kev)
+void
+u3j_free_hank(u3_noun kev)
 {
-  _cj_hank* han_u = u3to(_cj_hank, u3t(kev));
+  u3j_hank* han_u = u3to(u3j_hank, u3t(kev));
   if ( u3_none != han_u->hax ) {
     u3z(han_u->hax);
     u3j_site_lose(&(han_u->sit_u));
@@ -2326,7 +2317,7 @@ _cj_free_hank(u3_noun kev)
 void
 u3j_free(void)
 {
-  u3h_walk(u3R->jed.han_p, _cj_free_hank);
+  u3h_walk(u3R->jed.han_p, u3j_free_hank);
   u3h_free(u3R->jed.war_p);
   u3h_free(u3R->jed.cod_p);
   u3h_free(u3R->jed.han_p);
@@ -2348,10 +2339,9 @@ u3j_reclaim(void)
   // if ( &(u3H->rod_u) == u3R ) {
   //   u3j_ream();
   // }
-
   //  clear the jet hank cache
   //
-  u3h_walk(u3R->jed.han_p, _cj_free_hank);
+  u3h_walk(u3R->jed.han_p, u3j_free_hank);
   u3h_free(u3R->jed.han_p);
   u3R->jed.han_p = u3h_new();
 }
diff --git a/pkg/noun/jets.h b/pkg/noun/jets.h
index 6db106918c..9723a0d5f7 100644
--- a/pkg/noun/jets.h
+++ b/pkg/noun/jets.h
@@ -126,6 +126,13 @@
         u3p(u3j_fink) fin_p;          //  fine check
       } u3j_site;
 
+      /* u3j_hank: cached hook information.
+       */
+      typedef struct {
+        u3_weak  hax;                     //  axis of hooked inner core
+        u3j_site sit_u;                   //  call-site data
+      } u3j_hank;
+
   /** Globals.
   **/
     /* u3_Dash: jet dashboard.
@@ -292,6 +299,11 @@
         void
         u3j_free(void);
 
+      /* u3j_free_hank(): free an entry from the hank cache.
+      */
+        void
+        u3j_free_hank(u3_noun kev);
+
       /* u3j_reclaim(): clear ad-hoc persistent caches to reclaim memory.
       */
         void
diff --git a/pkg/noun/jets/c/dor.c b/pkg/noun/jets/c/dor.c
index dc463f7ae6..0c1e220afc 100644
--- a/pkg/noun/jets/c/dor.c
+++ b/pkg/noun/jets/c/dor.c
@@ -7,8 +7,8 @@
 
 
   u3_noun
-  u3qc_dor(u3_atom a,
-           u3_atom b)
+  u3qc_dor(u3_noun a,
+           u3_noun b)
   {
     if ( c3y == u3r_sing(a, b) ) {
       return c3y;
diff --git a/pkg/noun/jets/c/mor.c b/pkg/noun/jets/c/mor.c
index 6967a8a1b6..97ba1410bd 100644
--- a/pkg/noun/jets/c/mor.c
+++ b/pkg/noun/jets/c/mor.c
@@ -7,8 +7,8 @@
 
 
   u3_noun
-  u3qc_mor(u3_atom a,
-           u3_atom b)
+  u3qc_mor(u3_noun a,
+           u3_noun b)
   {
     c3_w c_w = u3r_mug(u3r_mug(a));
     c3_w d_w = u3r_mug(u3r_mug(b));
diff --git a/pkg/noun/jets/f/ut_crop.c b/pkg/noun/jets/f/ut_crop.c
index 1969a13a3d..189564d0c3 100644
--- a/pkg/noun/jets/f/ut_crop.c
+++ b/pkg/noun/jets/f/ut_crop.c
@@ -20,7 +20,7 @@ u3wfu_crop(u3_noun cor)
     u3_weak vet = u3r_at(u3qfu_van_vet, van);
     c3_m  fun_m = 141 + c3__crop + ((!!vet) << 8);
     u3_noun key = u3z_key_3(fun_m, sut, ref, bat);
-    u3_weak pro = u3z_find(key);
+    u3_weak pro = u3z_find(u3z_memo_toss, key);
 
     if ( u3_none != pro ) {
       u3z(key);
@@ -28,7 +28,7 @@ u3wfu_crop(u3_noun cor)
     }
     else {
       pro = u3n_nock_on(u3k(cor), u3k(u3x_at(u3x_bat, cor)));
-      return u3z_save(key, pro);
+      return u3z_save(u3z_memo_toss, key, pro);
     }
   }
 }
diff --git a/pkg/noun/jets/f/ut_fish.c b/pkg/noun/jets/f/ut_fish.c
index e7505b9345..e8acbd43cf 100644
--- a/pkg/noun/jets/f/ut_fish.c
+++ b/pkg/noun/jets/f/ut_fish.c
@@ -21,7 +21,7 @@ u3wfu_fish(u3_noun cor)
     u3_weak vet = u3r_at(u3qfu_van_vet, van);
     c3_m  fun_m = 141 + c3__fish + ((!!vet) << 8);
     u3_noun key = u3z_key_3(fun_m, sut, axe, bat);
-    u3_weak pro = u3z_find(key);
+    u3_weak pro = u3z_find(u3z_memo_toss, key);
 
     if ( u3_none != pro ) {
       u3z(key);
@@ -29,7 +29,7 @@ u3wfu_fish(u3_noun cor)
     }
     else {
       pro = u3n_nock_on(u3k(cor), u3k(u3x_at(u3x_bat, cor)));
-      return u3z_save(key, pro);
+      return u3z_save(u3z_memo_toss, key, pro);
     }
   }
 }
diff --git a/pkg/noun/jets/f/ut_fuse.c b/pkg/noun/jets/f/ut_fuse.c
index f9fac33a4d..8e4e1a6135 100644
--- a/pkg/noun/jets/f/ut_fuse.c
+++ b/pkg/noun/jets/f/ut_fuse.c
@@ -20,7 +20,7 @@ u3wfu_fuse(u3_noun cor)
     u3_weak vet = u3r_at(u3qfu_van_vet, van);
     c3_m  fun_m = 141 + c3__fuse + ((!!vet) << 8);
     u3_noun key = u3z_key_3(fun_m, sut, ref, bat);
-    u3_weak pro = u3z_find(key);
+    u3_weak pro = u3z_find(u3z_memo_toss, key);
 
     if ( u3_none != pro ) {
       u3z(key);
@@ -28,7 +28,7 @@ u3wfu_fuse(u3_noun cor)
     }
     else {
       pro = u3n_nock_on(u3k(cor), u3k(u3x_at(u3x_bat, cor)));
-      return u3z_save(key, pro);
+      return u3z_save(u3z_memo_toss, key, pro);
     }
   }
 }
diff --git a/pkg/noun/jets/f/ut_mint.c b/pkg/noun/jets/f/ut_mint.c
index fc8424854a..618e7291fd 100644
--- a/pkg/noun/jets/f/ut_mint.c
+++ b/pkg/noun/jets/f/ut_mint.c
@@ -22,7 +22,7 @@ u3wfu_mint(u3_noun cor)
     c3_m  fun_m = 141 + c3__mint;
     u3_noun vet = u3r_at(u3qfu_van_vet, van);
     u3_noun key = u3z_key_5(fun_m, vet, sut, gol, gen, bat);
-    u3_weak pro = u3z_find(key);
+    u3_weak pro = u3z_find(u3z_memo_toss, key);
 
     if ( u3_none != pro ) {
       u3z(key);
@@ -30,7 +30,7 @@ u3wfu_mint(u3_noun cor)
     }
     else {
       pro = u3n_nock_on(u3k(cor), u3k(u3x_at(u3x_bat, cor)));
-      return u3z_save(key, pro);
+      return u3z_save(u3z_memo_toss, key, pro);
     }
   }
 }
diff --git a/pkg/noun/jets/f/ut_mull.c b/pkg/noun/jets/f/ut_mull.c
index 98e62ca57e..767ab3c51a 100644
--- a/pkg/noun/jets/f/ut_mull.c
+++ b/pkg/noun/jets/f/ut_mull.c
@@ -23,7 +23,7 @@ u3wfu_mull(u3_noun cor)
     u3_weak vet = u3r_at(u3qfu_van_vet, van);
     c3_m  fun_m = 141 + c3__mull + ((!!vet) << 8);
     u3_noun key = u3z_key_5(fun_m, sut, gol, dox, gen, bat);
-    u3_weak pro = u3z_find(key);
+    u3_weak pro = u3z_find(u3z_memo_toss, key);
 
     if ( u3_none != pro ) {
       u3z(key);
@@ -31,7 +31,7 @@ u3wfu_mull(u3_noun cor)
     }
     else {
       pro = u3n_nock_on(u3k(cor), u3k(u3x_at(u3x_bat, cor)));
-      return u3z_save(key, pro);
+      return u3z_save(u3z_memo_toss, key, pro);
     }
   }
 }
diff --git a/pkg/noun/jets/f/ut_nest.c b/pkg/noun/jets/f/ut_nest.c
index 765081a5cb..9bc53bf0f9 100644
--- a/pkg/noun/jets/f/ut_nest.c
+++ b/pkg/noun/jets/f/ut_nest.c
@@ -27,7 +27,7 @@ u3wfu_nest_dext(u3_noun dext_core)
     u3_weak vet = u3r_at(u3qfu_van_vet, van);
     c3_m  fun_m = 141 + c3__dext + ((!!vet) << 8);
     u3_noun key = u3z_key_3(fun_m, sut, ref, bat);
-    u3_weak pro = u3z_find(key);
+    u3_weak pro = u3z_find(u3z_memo_toss, key);
 
     if ( u3_none != pro ) {
       u3z(key);
@@ -39,7 +39,7 @@ u3wfu_nest_dext(u3_noun dext_core)
       if ( ((c3y == pro) && (u3_nul == reg)) ||
            ((c3n == pro) && (u3_nul == seg)) )
       {
-        return u3z_save(key, pro);
+        return u3z_save(u3z_memo_toss, key, pro);
       }
       else {
         u3z(key);
diff --git a/pkg/noun/jets/f/ut_rest.c b/pkg/noun/jets/f/ut_rest.c
index 3fdbed23b0..87ff60fa68 100644
--- a/pkg/noun/jets/f/ut_rest.c
+++ b/pkg/noun/jets/f/ut_rest.c
@@ -20,7 +20,7 @@ u3wfu_rest(u3_noun cor)
     u3_weak vet = u3r_at(u3qfu_van_vet, van);
     c3_m  fun_m = 141 + c3__rest + ((!!vet) << 8);
     u3_noun key = u3z_key_3(fun_m, sut, leg, bat);
-    u3_weak pro = u3z_find(key);
+    u3_weak pro = u3z_find(u3z_memo_toss, key);
 
     if ( u3_none != pro ) {
       u3z(key);
@@ -28,7 +28,7 @@ u3wfu_rest(u3_noun cor)
     }
     else {
       pro = u3n_nock_on(u3k(cor), u3k(u3x_at(u3x_bat, cor)));
-      return u3z_save(key, pro);
+      return u3z_save(u3z_memo_toss, key, pro);
     }
   }
 }
diff --git a/pkg/noun/jets/tree.c b/pkg/noun/jets/tree.c
index c15e29ba8e..b0264327d1 100644
--- a/pkg/noun/jets/tree.c
+++ b/pkg/noun/jets/tree.c
@@ -2224,11 +2224,8 @@ static u3j_core _139_qua_d[] =
   { "mole", 7, _140_qua_mole_a, 0, no_hashes },
   { "mule", 7, _140_qua_mule_a, 0, no_hashes },
 
-  //  XX disabled, implicated in memory corruption
-  //  write tests and re-enable
-  //
-  // { "scot", 7, _140_qua_scot_a, 0, no_hashes },
-  // { "scow", 7, _140_qua_scow_a, 0, no_hashes },
+  { "scot", 7, _140_qua_scot_a, 0, no_hashes },
+  { "scow", 7, _140_qua_scow_a, 0, no_hashes },
   { "slaw", 7, _140_qua_slaw_a, 0, no_hashes },
   {}
 };
diff --git a/pkg/noun/manage.c b/pkg/noun/manage.c
index 909cfe86b9..279fe5fea5 100644
--- a/pkg/noun/manage.c
+++ b/pkg/noun/manage.c
@@ -1,6 +1,8 @@
 /// @file
 
-#include "manage.h"
+#include "pkg/noun/manage.h"
+#include "pkg/noun/v2/manage.h"
+#include "pkg/noun/v3/manage.h"
 
 #include <ctype.h>
 #include <errno.h>
@@ -473,9 +475,8 @@ u3m_mark(FILE* fil_u)
 static void
 _pave_parts(void)
 {
-  // TODO: pass `u3_Host.ops_u.hap_w` into `noun` library as an argument and use
-  // as size of memo cache.
-  u3R->cax.har_p = u3h_new_cache(50000);
+  u3R->cax.har_p = u3h_new_cache(u3C.hap_w);  //  transient
+  u3R->cax.per_p = u3h_new_cache(u3C.per_w);  //  persistent
   u3R->jed.war_p = u3h_new();
   u3R->jed.cod_p = u3h_new();
   u3R->jed.han_p = u3h_new();
@@ -488,7 +489,7 @@ _pave_parts(void)
 static u3_road*
 _pave_road(c3_w* rut_w, c3_w* mat_w, c3_w* cap_w, c3_w siz_w)
 {
-  c3_dessert(((uintptr_t)rut_w & u3C.balign_d-1) == 0);
+  c3_dessert(((uintptr_t)rut_w & u3a_balign-1) == 0);
   u3_road* rod_u = (void*) mat_w;
 
   //  enable in case of corruption
@@ -529,8 +530,8 @@ _pave_north(c3_w* mem_w, c3_w siz_w, c3_w len_w, c3_o kid_o)
   //    00~~~|R|---|H|######|C|+++|M|~~~FF
   //                                ^--u3R which _pave_road returns (u3H for home road)
   //
-  c3_w* mat_w = c3_align(mem_w + len_w - siz_w, u3C.balign_d, C3_ALGLO);
-  c3_w* rut_w = c3_align(mem_w, u3C.balign_d, C3_ALGHI);
+  c3_w* mat_w = c3_align(mem_w + len_w - siz_w, u3a_balign, C3_ALGLO);
+  c3_w* rut_w = c3_align(mem_w, u3a_balign, C3_ALGHI);
   c3_w* cap_w = mat_w;
 
   if ( c3y == kid_o ) {
@@ -560,8 +561,8 @@ _pave_south(c3_w* mem_w, c3_w siz_w, c3_w len_w)
   //    00~~~|M|+++|C|######|H|---|R|~~~FFF
   //         ^---u3R which _pave_road returns
   //
-  c3_w* mat_w = c3_align(mem_w, u3C.balign_d, C3_ALGHI);
-  c3_w* rut_w = c3_align(mem_w + len_w, u3C.balign_d, C3_ALGLO);
+  c3_w* mat_w = c3_align(mem_w, u3a_balign, C3_ALGHI);
+  c3_w* rut_w = c3_align(mem_w + len_w, u3a_balign, C3_ALGLO);
   c3_w* cap_w = mat_w + siz_w;
 
   u3e_ward(u3of(c3_w, cap_w) - 1, u3of(c3_w, rut_w));
@@ -574,12 +575,9 @@ _pave_south(c3_w* mem_w, c3_w siz_w, c3_w len_w)
 static void
 _pave_home(void)
 {
-  /* a pristine home road will always have compressed references */
-  u3a_config_loom(U3V_VERLAT);
-
-  c3_w* mem_w = u3_Loom + u3C.walign_w;
+  c3_w* mem_w = u3_Loom + u3a_walign;
   c3_w  siz_w = c3_wiseof(u3v_home);
-  c3_w  len_w = u3C.wor_i - u3C.walign_w;
+  c3_w  len_w = u3C.wor_i - u3a_walign;
 
   u3H = (void *)_pave_north(mem_w, siz_w, len_w, c3n);
   u3H->ver_w = U3V_VERLAT;
@@ -597,14 +595,29 @@ static void
 _find_home(void)
 {
   c3_w ver_w = *(u3_Loom + u3C.wor_i - 1);
-  u3a_config_loom(ver_w);
+  c3_o mig_o = c3y;  //  did we migrate?
+
+  switch ( ver_w ) {
+    case U3V_VER1: u3m_v2_migrate();
+    case U3V_VER2: u3m_v3_migrate();
+    case U3V_VER3: {
+      mig_o = c3n;
+      break;
+    }
+    default: {
+      fprintf(stderr, "loom: checkpoint version mismatch: "
+                      "have %u, need %u\r\n",
+                      ver_w, U3V_VERLAT);
+      abort();
+    }
+  }
 
   //  NB: the home road is always north
   //
-  c3_w* mem_w = u3_Loom + u3C.walign_w;
+  c3_w* mem_w = u3_Loom + u3a_walign;
   c3_w  siz_w = c3_wiseof(u3v_home);
-  c3_w  len_w = u3C.wor_i - u3C.walign_w;
-  c3_w* mat_w = c3_align(mem_w + len_w - siz_w, u3C.balign_d, C3_ALGLO);
+  c3_w  len_w = u3C.wor_i - u3a_walign;
+  c3_w* mat_w = c3_align(mem_w + len_w - siz_w, u3a_balign, C3_ALGLO);
 
   u3H = (void *)mat_w;
   u3R = &u3H->rod_u;
@@ -616,7 +629,7 @@ _find_home(void)
 
   //  check for obvious corruption
   //
-  {
+  if ( c3n == mig_o ) {
     c3_w    nor_w, sou_w;
     u3_post low_p, hig_p;
     u3m_water(&low_p, &hig_p);
@@ -642,18 +655,6 @@ _find_home(void)
   /* As a further guard against any sneaky loom corruption */
   u3a_loom_sane();
 
-  if (U3V_VERLAT > ver_w) {
-    u3m_migrate(U3V_VERLAT);
-    u3a_config_loom(U3V_VERLAT);
-  }
-  else if ( U3V_VERLAT < ver_w ) {
-    fprintf(stderr, "loom: checkpoint version mismatch: "
-            "have %u, need %u\r\n",
-            ver_w,
-            U3V_VERLAT);
-    abort();
-  }
-
   _rod_vaal(u3R);
 }
 
@@ -748,13 +749,6 @@ u3m_dump(void)
 c3_i
 u3m_bail(u3_noun how)
 {
-  if ( &(u3H->rod_u) == u3R ) {
-    //  XX set exit code
-    //
-    fprintf(stderr, "home: bailing out\r\n");
-    abort();
-  }
-
   //  printf some metadata
   //
   switch ( how ) {
@@ -779,6 +773,13 @@ u3m_bail(u3_noun how)
     }
   }
 
+  if ( &(u3H->rod_u) == u3R ) {
+    //  XX set exit code
+    //
+    fprintf(stderr, "home: bailing out\r\n");
+    abort();
+  }
+
   //  intercept fatal errors
   //
   switch ( how ) {
@@ -865,7 +866,7 @@ u3m_leap(c3_w pad_w)
     }
     pad_w += c3_wiseof(u3a_road);
     len_w = u3a_open(u3R) - pad_w;
-    c3_align(len_w, u3C.walign_w, C3_ALGHI);
+    c3_align(len_w, u3a_walign, C3_ALGHI);
   }
 
   /* Allocate a region on the cap.
@@ -996,6 +997,7 @@ u3m_love(u3_noun pro)
   //
   u3p(u3h_root) byc_p = u3R->byc.har_p;
   u3a_jets      jed_u = u3R->jed;
+  u3p(u3h_root) per_p = u3R->cax.per_p;
 
   //  fallback to parent road (child heap on parent's stack)
   //
@@ -1009,6 +1011,7 @@ u3m_love(u3_noun pro)
   //
   u3j_reap(&jed_u);
   u3n_reap(byc_p);
+  u3z_reap(u3z_memo_keep, per_p);
 
   //  pop the stack
   //
@@ -1760,14 +1763,6 @@ _cm_limits(void)
 # endif
 }
 
-/* u3m_backup(): copy snapshot to .urb/bhk (if it doesn't exist yet).
-*/
-c3_o
-u3m_backup(c3_o ovw_o)
-{
-  return u3e_backup(ovw_o);
-}
-
 /* u3m_fault(): handle a memory event with libsigsegv protocol.
 */
 c3_i
@@ -2088,6 +2083,42 @@ u3m_stop()
   u3je_secp_stop();
 }
 
+/* u3m_pier(): make a pier.
+*/
+c3_c*
+u3m_pier(c3_c* dir_c)
+{
+  c3_c ful_c[8193];
+
+  u3C.dir_c = dir_c;
+
+  snprintf(ful_c, 8192, "%s", dir_c);
+  if ( c3_mkdir(ful_c, 0700) ) {
+    if ( EEXIST != errno ) {
+      fprintf(stderr, "loom: pier create: %s\r\n", strerror(errno));
+      exit(1);
+    }
+  }
+
+  snprintf(ful_c, 8192, "%s/.urb", dir_c);
+  if ( c3_mkdir(ful_c, 0700) ) {
+    if ( EEXIST != errno ) {
+      fprintf(stderr, "loom: .urb create: %s\r\n", strerror(errno));
+      exit(1);
+    }
+  }
+
+  snprintf(ful_c, 8192, "%s/.urb/chk", dir_c);
+  if ( c3_mkdir(ful_c, 0700) ) {
+    if ( EEXIST != errno ) {
+      fprintf(stderr, "loom: .urb/chk create: %s\r\n", strerror(errno));
+      exit(1);
+    }
+  }
+
+  return strdup(dir_c);
+}
+
 /* u3m_boot(): start the u3 system. return next event, starting from 1.
 */
 c3_d
@@ -2103,7 +2134,7 @@ u3m_boot(c3_c* dir_c, size_t len_i)
 
   /* Activate the storage system.
   */
-  nuu_o = u3e_live(c3n, dir_c);
+  nuu_o = u3e_live(c3n, u3m_pier(dir_c));
 
   /* Activate tracing.
   */
@@ -2172,7 +2203,7 @@ u3m_boot_lite(size_t len_i)
   return 0;
 }
 
-/* u3m_reclaim: clear persistent caches to reclaim memory
+/* u3m_reclaim: clear persistent caches to reclaim memory.
 */
 void
 u3m_reclaim(void)
@@ -2188,7 +2219,7 @@ u3m_reclaim(void)
 static void
 _cm_pack_rewrite(void)
 {
-  //  XX fix u3a_rewrit* to support south roads
+  //  XX fix u3a_rewrite* to support south roads
   //
   u3_assert( &(u3H->rod_u) == u3R );
 
@@ -2226,158 +2257,3 @@ u3m_pack(void)
 
   return (u3a_open(u3R) - pre_w);
 }
-
-static void
-_migrate_reclaim()
-{
-  fprintf(stderr, "loom: migration reclaim\r\n");
-  u3m_reclaim();
-}
-
-static void
-_migrate_seek(const u3a_road *rod_u)
-{
-  /*
-    very much like u3a_pack_seek with the following changes:
-    - there is no need to account for free space as |pack is performed before
-      the migration
-    - odd sized boxes will be padded by one word to achieve an even size
-    - rut will be moved from one word ahead of u3_Loom to two words ahead
-  */
-  c3_w *    box_w = u3a_into(rod_u->rut_p);
-  c3_w *    end_w = u3a_into(rod_u->hat_p);
-  u3_post   new_p = (rod_u->rut_p + 1 + c3_wiseof(u3a_box));
-  u3a_box * box_u = (void *)box_w;
-
-  fprintf(stderr, "loom: migration seek\r\n");
-
-  for (; box_w < end_w
-         ; box_w += box_u->siz_w
-         , box_u = (void*)box_w)
-    {
-      if (!box_u->use_w)
-        continue;
-      u3_assert(box_u->siz_w);
-      u3_assert(box_u->use_w);
-      box_w[box_u->siz_w - 1] = new_p;
-      new_p = c3_align(new_p + box_u->siz_w, 2, C3_ALGHI);
-    }
-}
-
-static void
-_migrate_rewrite()
-{
-  fprintf(stderr, "loom: migration rewrite\r\n");
-
-  /* So that rewritten pointers are compressed, this flag is set */
-  u3C.migration_state = MIG_REWRITE_COMPRESSED;
-  _cm_pack_rewrite();
-  u3C.migration_state = MIG_NONE;
-}
-
-static void
-_migrate_move(u3a_road *rod_u)
-{
-  fprintf(stderr, "loom: migration move\r\n");
-
-  c3_z hiz_z = u3a_heap(rod_u) * sizeof(c3_w);
-
-  /* calculate required shift distance to prevent write head overlapping read head */
-  c3_w  off_w = 1;  /* at least 1 word because u3R->rut_p migrates from 1 to 2 */
-  for (u3a_box *box_u = u3a_into(rod_u->rut_p)
-         ; (void *)box_u < u3a_into(rod_u->hat_p)
-         ; box_u = (void *)((c3_w *)box_u + box_u->siz_w))
-    off_w += box_u->siz_w & 1; /* odd-sized boxes are padded by one word */
-
-  /* shift */
-  memmove(u3a_into(u3H->rod_u.rut_p + off_w),
-          u3a_into(u3H->rod_u.rut_p),
-          hiz_z);
-  /* manually zero the former rut */
-  *(c3_w *)u3a_into(rod_u->rut_p) = 0;
-
-  /* relocate boxes to DWORD-aligned addresses stored in trailing size word */
-  c3_w *box_w = u3a_into(rod_u->rut_p + off_w);
-  c3_w *end_w = u3a_into(rod_u->hat_p + off_w);
-  u3a_box *old_u = (void *)box_w;
-  c3_w siz_w = old_u->siz_w;
-  u3p(c3_w) new_p = rod_u->rut_p + 1 + c3_wiseof(u3a_box);
-  c3_w *new_w;
-
-  for (; box_w < end_w
-         ; box_w += siz_w
-         , old_u = (void *)box_w
-         , siz_w = old_u->siz_w) {
-    old_u->use_w &= 0x7fffffff;
-
-    if (!old_u->use_w)
-      continue;
-
-    new_w = (void *)u3a_botox(u3a_into(new_p));
-    u3_assert(box_w[siz_w - 1] == new_p);
-    u3_assert(new_w <= box_w);
-
-    c3_w i_w;
-    for (i_w = 0; i_w < siz_w - 1; i_w++)
-      new_w[i_w] = box_w[i_w];
-
-    if (siz_w & 1) {
-      new_w[i_w++] = 0;         /* pad odd sized boxes */
-      new_w[i_w++] = siz_w + 1; /* restore trailing size word */
-      new_w[0] = siz_w + 1;     /* and the leading size word */
-    }
-    else {
-      new_w[i_w++] = siz_w;
-    }
-
-    new_p += i_w;
-  }
-
-  /* restore proper heap state */
-  rod_u->rut_p = 2;
-  rod_u->hat_p = new_p - c3_wiseof(u3a_box);
-
-  /* like |pack, clear the free lists and cell allocator */
-  for (c3_w i_w = 0; i_w < u3a_fbox_no; i_w++)
-    u3R->all.fre_p[i_w] = 0;
-
-  u3R->all.fre_w = 0;
-  u3R->all.cel_p = 0;
-}
-
-
-/* u3m_migrate: perform loom migration if necessary.
-   ver_w - target version
-*/
-void
-u3m_migrate(u3v_version ver_w)
-{
-  if (u3H->ver_w == ver_w)
-    return;
-
-  /* 1 -> 2 is all that is currently supported */
-  c3_dessert(u3H->ver_w == U3V_VER1 &&
-             ver_w == U3V_VER2);
-
-  /* only home road migration is supported */
-  c3_dessert((uintptr_t)u3H == (uintptr_t)u3R);
-
-  fprintf(stderr, "loom: migration running. This may take several minutes to perform.\r\n");
-  fprintf(stderr, "loom: have version: %"PRIc3_w" migrating to version: %"PRIc3_w"\r\n",
-          u3H->ver_w, ver_w);
-
-  /* packing first simplifies migration logic and minimizes required buffer space */
-  u3m_pack();
-
-  /* perform the migration in a pattern similar to |pack */
-  _migrate_reclaim();
-  _migrate_seek(&u3H->rod_u);
-  _migrate_rewrite();
-  _migrate_move(&u3H->rod_u);
-
-  /* finally update the version and commit to disk */
-  u3H->ver_w = ver_w;
-  /* extra assurance we haven't corrupted the loom before writing to disk */
-  u3a_loom_sane();
-  u3m_save();
-}
diff --git a/pkg/noun/manage.h b/pkg/noun/manage.h
index 297585c486..14f9cc503d 100644
--- a/pkg/noun/manage.h
+++ b/pkg/noun/manage.h
@@ -3,6 +3,9 @@
 #ifndef U3_MANAGE_H
 #define U3_MANAGE_H
 
+#include "v1/manage.h"
+#include "v2/manage.h"
+
 #include "c3.h"
 #include "types.h"
 #include "version.h"
@@ -14,6 +17,11 @@
         c3_d
         u3m_boot(c3_c* dir_c, size_t len_i);
 
+      /* u3m_pier(): make a pier.
+      */
+        c3_c*
+        u3m_pier(c3_c* dir_c);
+
       /* u3m_boot_lite(): start without checkpointing.
       */
         c3_d
@@ -180,7 +188,7 @@
         void
         u3m_wall(u3_noun wol);
 
-      /* u3m_reclaim: clear persistent caches to reclaim memory
+      /* u3m_reclaim: clear persistent caches to reclaim memory.
       */
         void
         u3m_reclaim(void);
@@ -190,10 +198,4 @@
         c3_w
         u3m_pack(void);
 
-      /* u3m_migrate: perform loom migration if necessary.
-         ver_w - target version
-      */
-        void
-        u3m_migrate(u3v_version ver_w);
-
 #endif /* ifndef U3_MANAGE_H */
diff --git a/pkg/noun/nock.c b/pkg/noun/nock.c
index c012577bf4..daeefdea61 100644
--- a/pkg/noun/nock.c
+++ b/pkg/noun/nock.c
@@ -619,7 +619,7 @@ _n_melt(u3_noun ops, c3_w* byc_w, c3_w* cal_w,
 
         case SKIB: case SLIB: {
           c3_l tot_l = 0,
-               sip_l = u3h(u3t(op));
+               sip_l = u3h(u3t(u3t(op)));
           c3_w j_w, k_w = i_w;
           for ( j_w = 0; j_w < sip_l; ++j_w ) {
             tot_l += siz_y[++k_w];
@@ -830,7 +830,9 @@ _n_prog_asm(u3_noun ops, u3n_prog* pog_u, u3_noun sip)
           _n_prog_asm_inx(buf_y, &i_w, mem_s, cod);
           mem_u        = &(pog_u->mem_u.sot_u[mem_s++]);
           mem_u->sip_l = sip_l;
-          mem_u->key   = u3k(u3t(u3t(op)));
+          // [op_y, cid, mem_w, nef]
+          mem_u->key   = u3k(u3t(u3t(u3t(op))));
+          mem_u->cid   = u3h(u3t(op));
           break;
         }
 
@@ -1117,16 +1119,21 @@ _n_bint(u3_noun* ops, u3_noun hif, u3_noun nef, c3_o los_o, c3_o tel_o)
         c3_w mem_w = 0;
         c3_y op_y;
 
-        // we just throw away the hint (why is this not a static hint?)
         tot_w += _n_comp(ops, hod, c3n, c3n);
         ++tot_w; _n_emit(ops, TOSS);
 
-        // memoizing code always loses TOS because SAVE needs [pro key]
         mem_w += _n_comp(&mem, nef, c3y, c3n);
         ++mem_w; _n_emit(&mem, SAVE);
 
         op_y   = (c3y == los_o) ? SLIB : SKIB; // overflows to SLIS / SKIS
-        ++tot_w; _n_emit(ops, u3nt(op_y, mem_w, u3k(nef)));
+        u3z_cid cid = u3z_memo_toss;
+        {
+          u3_weak con = u3r_skip(hod);
+          if ( (u3_none != con) && (c3y == u3du(con)) ) {
+            cid = u3z_memo_keep;
+          }
+        }
+        ++tot_w; _n_emit(ops, u3nq(op_y, cid, mem_w, u3k(nef)));
         tot_w += mem_w; _n_apen(ops, mem);
         break;
       }
@@ -2610,9 +2617,9 @@ _n_burn(u3n_prog* pog_u, u3_noun bus, c3_ys mov, c3_ys off)
     skim_out:
       o     = u3k(mem_u->key);
       x     = u3nc(x, o);
-      o     = u3z_find_m(144 + c3__nock, x);
+      o     = u3z_find_m(mem_u->cid, 144 + c3__nock, x);
       if ( u3_none == o ) {
-        _n_push(mov, off, x);
+        _n_push(mov, off, u3nc(mem_u->cid, x));
         _n_push(mov, off, u3k(u3h(x)));
       }
       else {
@@ -2623,11 +2630,16 @@ _n_burn(u3n_prog* pog_u, u3_noun bus, c3_ys mov, c3_ys off)
       BURN();
 
     do_save:
-      x   = _n_pep(mov, off);
+      x   = _n_pep(mov, off);  // product
       top = _n_peek(off);
       o   = *top;
-      if ( &(u3H->rod_u) != u3R ) {
-        u3z_save_m(144 + c3__nock, o, x);
+      if ( ( u3z_memo_toss == u3h(o) )
+         ? ( &(u3H->rod_u) != u3R )
+         : ( 0 == u3R->ski.gul ) ) {  //  prevents userspace from persistence
+        u3z_save_m(u3h(o), 144 + c3__nock, u3t(o), x);
+      }
+      else if ( u3z_memo_keep == u3h(o) ) {
+        fprintf(stderr, "\r\nnock: userspace can't save to persistent cache\r\n");
       }
       *top = x;
       u3z(o);
@@ -2853,6 +2865,7 @@ _cn_take_prog_dat(u3n_prog* dst_u, u3n_prog* src_u)
     u3n_memo* ome_u = &(dst_u->mem_u.sot_u[i_w]);
     ome_u->sip_l    = emo_u->sip_l;
     ome_u->key      = u3a_take(emo_u->key);
+    ome_u->cid      = emo_u->cid;
   }
 
   for ( i_w = 0; i_w < src_u->cal_u.len_w; ++i_w ) {
@@ -2908,6 +2921,7 @@ _cn_merge_prog_dat(u3n_prog* dst_u, u3n_prog* src_u)
     u3z(emo_u->key);
     emo_u->sip_l    = ome_u->sip_l;
     emo_u->key      = ome_u->key;
+    emo_u->cid      = ome_u->cid;
   }
 
   for ( i_w = 0; i_w < src_u->cal_u.len_w; ++i_w ) {
diff --git a/pkg/noun/nock.h b/pkg/noun/nock.h
index a60b0ece58..e680327c74 100644
--- a/pkg/noun/nock.h
+++ b/pkg/noun/nock.h
@@ -8,6 +8,7 @@
 #include "c3.h"
 #include "jets.h"
 #include "types.h"
+#include "zave.h"
 
   /** Data structures.
   ***
@@ -18,6 +19,7 @@
   typedef struct {
     c3_l    sip_l;
     u3_noun key;
+    u3z_cid cid;
   } u3n_memo;
 
   /* u3n_prog: program compiled from nock
diff --git a/pkg/noun/options.h b/pkg/noun/options.h
index 1bd65320fc..29ca6ce9d9 100644
--- a/pkg/noun/options.h
+++ b/pkg/noun/options.h
@@ -15,16 +15,10 @@
         c3_c*   dir_c;                        //  execution directory (pier)
         c3_c*   eph_c;                        //  ephemeral file
         c3_w    wag_w;                        //  flags (both ways)
-        c3_w    vits_w;                       //  number of virtual bits in reference
-        c3_w    walign_w;                     //  word alignment
-        c3_d    balign_d;                     //  byte alignment
-        enum {
-          MIG_NONE,
-          MIG_REWRITE_COMPRESSED,
-        } migration_state;
-
         size_t  wor_i;                        //  loom word-length (<= u3a_words)
         c3_w    tos_w;                        //  loom toss skip-length
+        c3_w    hap_w;                        //  transient memoization cache size
+        c3_w    per_w;                        //  persistent memoization cache size
         void (*stderr_log_f)(c3_c*);          //  errors from c code
         void (*slog_f)(u3_noun);              //  function pointer for slog
         void (*sign_hold_f)(void);            //  suspend system signal regime
diff --git a/pkg/noun/retrieve.c b/pkg/noun/retrieve.c
index d1790c7320..8f9847ff92 100644
--- a/pkg/noun/retrieve.c
+++ b/pkg/noun/retrieve.c
@@ -9,6 +9,35 @@
 #include "trace.h"
 #include "xtract.h"
 
+
+//  declarations of inline functions
+//
+c3_o
+u3r_cell(u3_noun a, u3_noun* b, u3_noun* c);
+c3_o
+u3r_trel(u3_noun a, u3_noun* b, u3_noun* c, u3_noun* d);
+c3_o
+u3r_qual(u3_noun  a,
+         u3_noun* b,
+         u3_noun* c,
+         u3_noun* d,
+         u3_noun* e);
+c3_o
+u3r_quil(u3_noun  a,
+         u3_noun* b,
+         u3_noun* c,
+         u3_noun* d,
+         u3_noun* e,
+         u3_noun* f);
+c3_o
+u3r_hext(u3_noun  a,
+         u3_noun* b,
+         u3_noun* c,
+         u3_noun* d,
+         u3_noun* e,
+         u3_noun* f,
+         u3_noun* g);
+
 /* _frag_word(): fast fragment/branch prediction for top word.
 */
 static u3_weak
@@ -833,27 +862,6 @@ u3r_bite(u3_noun bite, u3_atom* bloq, u3_atom *step)
   }
 }
 
-/* u3r_cell():
-**
-**   Factor (a) as a cell (b c).
-*/
-c3_o
-u3r_cell(u3_noun  a,
-           u3_noun* b,
-           u3_noun* c)
-{
-  u3_assert(u3_none != a);
-
-  if ( _(u3a_is_atom(a)) ) {
-    return c3n;
-  }
-  else {
-    if ( b ) *b = u3a_h(a);
-    if ( c ) *c = u3a_t(a);
-    return c3y;
-  }
-}
-
 /* u3r_p():
 **
 **   & [0] if [a] is of the form [b *c].
@@ -937,90 +945,6 @@ u3r_pqrs(u3_noun  a,
   else return c3n;
 }
 
-/* u3r_trel():
-**
-**   Factor (a) as a trel (b c d).
-*/
-c3_o
-u3r_trel(u3_noun a,
-           u3_noun *b,
-           u3_noun *c,
-           u3_noun *d)
-{
-  u3_noun guf;
-
-  if ( (c3y == u3r_cell(a, b, &guf)) &&
-       (c3y == u3r_cell(guf, c, d)) ) {
-    return c3y;
-  }
-  else {
-    return c3n;
-  }
-}
-
-/* u3r_qual():
-**
-**   Factor (a) as a qual (b c d e).
-*/
-c3_o
-u3r_qual(u3_noun  a,
-           u3_noun* b,
-           u3_noun* c,
-           u3_noun* d,
-           u3_noun* e)
-{
-  u3_noun guf;
-
-  if ( (c3y == u3r_cell(a, b, &guf)) &&
-       (c3y == u3r_trel(guf, c, d, e)) ) {
-    return c3y;
-  }
-  else return c3n;
-}
-
-/* u3r_quil():
-**
-**   Factor (a) as a quil (b c d e f).
-*/
-c3_o
-u3r_quil(u3_noun  a,
-           u3_noun* b,
-           u3_noun* c,
-           u3_noun* d,
-           u3_noun* e,
-           u3_noun* f)
-{
-  u3_noun guf;
-
-  if ( (c3y == u3r_cell(a, b, &guf)) &&
-       (c3y == u3r_qual(guf, c, d, e, f)) ) {
-    return c3y;
-  }
-  else return c3n;
-}
-
-/* u3r_hext():
-**
-**   Factor (a) as a hext (b c d e f g)
-*/
-c3_o
-u3r_hext(u3_noun  a,
-           u3_noun* b,
-           u3_noun* c,
-           u3_noun* d,
-           u3_noun* e,
-           u3_noun* f,
-           u3_noun* g)
-{
-  u3_noun guf;
-
-  if ( (c3y == u3r_cell(a, b, &guf)) &&
-       (c3y == u3r_quil(guf, c, d, e, f, g)) ) {
-    return c3y;
-  }
-  else return c3n;
-}
-
 /* u3r_met():
 **
 **   Return the size of (b) in bits, rounded up to
@@ -1903,3 +1827,29 @@ u3r_mug(u3_noun veb)
 
   return mug_l;
 }
+
+/* u3r_skip():
+**
+**  Extract a constant from a formula, ignoring
+**  safe/static hints, doing no computation.
+*/
+u3_weak
+u3r_skip(u3_noun fol)
+{
+  while ( c3y == u3du(fol) ) {
+    switch ( u3h(fol) ) {
+      default: return u3_none;
+      case 1:  return u3t(fol);
+      case 11: {
+        u3_noun arg = u3t(fol),
+                hod = u3h(arg);
+
+        if ( (c3y == u3du(hod)) && (u3_none == u3r_skip(u3t(hod))) ) {
+          return u3_none;
+        }
+        fol = u3t(arg);
+      }
+    }
+  }
+  return u3_none;
+}
diff --git a/pkg/noun/retrieve.h b/pkg/noun/retrieve.h
index a98a5e4697..7423ad9f49 100644
--- a/pkg/noun/retrieve.h
+++ b/pkg/noun/retrieve.h
@@ -4,11 +4,107 @@
 #define U3_RETRIEVE_H
 
 #include "c3.h"
+#include "allocate.h"
+#include "error.h"
 #include "gmp.h"
 #include "types.h"
 
     /** u3r_*: read without ever crashing.
     **/
+
+      /* u3r_cell(): factor (a) as a cell (b c).
+      */
+        inline c3_o
+        u3r_cell(u3_noun a, u3_noun* b, u3_noun* c)
+        {
+          u3a_cell* cel_u;
+
+          u3_assert(u3_none != a);
+
+          if ( c3y == u3a_is_cell(a) ) {
+            cel_u = u3a_to_ptr(a);
+            if ( b ) *b = cel_u->hed;
+            if ( c ) *c = cel_u->tel;
+            return c3y;
+          }
+          else {
+            return c3n;
+          }
+        }
+
+      /* u3r_trel(): factor (a) as a trel (b c d).
+      */
+        inline c3_o
+        u3r_trel(u3_noun a, u3_noun *b, u3_noun *c, u3_noun *d)
+        {
+          u3_noun guf;
+
+          if ( (c3y == u3r_cell(a, b, &guf)) &&
+               (c3y == u3r_cell(guf, c, d)) ) {
+            return c3y;
+          }
+          else {
+            return c3n;
+          }
+        }
+
+      /* u3r_qual(): factor (a) as a qual (b c d e).
+      */
+        inline c3_o
+        u3r_qual(u3_noun  a,
+                 u3_noun* b,
+                 u3_noun* c,
+                 u3_noun* d,
+                 u3_noun* e)
+        {
+          u3_noun guf;
+
+          if ( (c3y == u3r_cell(a, b, &guf)) &&
+               (c3y == u3r_trel(guf, c, d, e)) ) {
+            return c3y;
+          }
+          else return c3n;
+        }
+
+      /* u3r_quil(): factor (a) as a quil (b c d e f).
+      */
+        inline c3_o
+        u3r_quil(u3_noun  a,
+                 u3_noun* b,
+                 u3_noun* c,
+                 u3_noun* d,
+                 u3_noun* e,
+                 u3_noun* f)
+        {
+          u3_noun guf;
+
+          if ( (c3y == u3r_cell(a, b, &guf)) &&
+               (c3y == u3r_qual(guf, c, d, e, f)) ) {
+            return c3y;
+          }
+          else return c3n;
+        }
+
+      /* u3r_hext(): factor (a) as a hext (b c d e f g)
+      */
+        inline c3_o
+        u3r_hext(u3_noun  a,
+                 u3_noun* b,
+                 u3_noun* c,
+                 u3_noun* d,
+                 u3_noun* e,
+                 u3_noun* f,
+                 u3_noun* g)
+        {
+          u3_noun guf;
+
+          if ( (c3y == u3r_cell(a, b, &guf)) &&
+               (c3y == u3r_quil(guf, c, d, e, f, g)) ) {
+            return c3y;
+          }
+          else return c3n;
+        }
+
       /* u3r_at(): fragment `a` of `b`, or u3_none.
       */
         u3_weak
@@ -183,61 +279,6 @@
         c3_o
         u3r_bite(u3_noun bite, u3_atom* bloq, u3_atom *step);
 
-      /* u3r_cell():
-      **
-      **   Divide `a` as a cell `[b c]`.
-      */
-        c3_o
-        u3r_cell(u3_noun  a,
-                 u3_noun* b,
-                 u3_noun* c);
-
-      /* u3r_trel():
-      **
-      **   Divide `a` as a trel `[b c d]`.
-      */
-        c3_o
-        u3r_trel(u3_noun  a,
-                 u3_noun* b,
-                 u3_noun* c,
-                 u3_noun* d);
-
-      /* u3r_qual():
-      **
-      **   Divide (a) as a qual [b c d e].
-      */
-        c3_o
-        u3r_qual(u3_noun  a,
-                 u3_noun* b,
-                 u3_noun* c,
-                 u3_noun* d,
-                 u3_noun* e);
-
-      /* u3r_quil():
-      **
-      **   Divide (a) as a quil [b c d e f].
-      */
-        c3_o
-        u3r_quil(u3_noun  a,
-                 u3_noun* b,
-                 u3_noun* c,
-                 u3_noun* d,
-                 u3_noun* e,
-                 u3_noun* f);
-
-      /* u3r_hext():
-      **
-      **   Divide (a) as a hext [b c d e f g].
-      */
-        c3_o
-        u3r_hext(u3_noun  a,
-                 u3_noun* b,
-                 u3_noun* c,
-                 u3_noun* d,
-                 u3_noun* e,
-                 u3_noun* f,
-                 u3_noun* g);
-
       /* u3r_p():
       **
       **   & [0] if [a] is of the form [b *c].
@@ -486,4 +527,12 @@
         c3_y*
         u3r_tape(u3_noun a);
 
+      /* u3r_skip():
+      **
+      **  Extract a constant from a formula, ignoring
+      **  safe/static hints, doing no computation.
+      */
+        u3_weak
+        u3r_skip(u3_noun fol);
+
 #endif /* ifndef U3_RETRIEVE_H */
diff --git a/pkg/noun/trace.c b/pkg/noun/trace.c
index 8768531d62..fd33169e8d 100644
--- a/pkg/noun/trace.c
+++ b/pkg/noun/trace.c
@@ -299,7 +299,7 @@ u3t_flee(void)
 /*  u3t_trace_open(): opens a trace file and writes the preamble.
 */
 void
-u3t_trace_open(c3_c* dir_c)
+u3t_trace_open(const c3_c* dir_c)
 {
   c3_c fil_c[2048];
 
diff --git a/pkg/noun/trace.h b/pkg/noun/trace.h
index 667cdfae4b..695a5fe133 100644
--- a/pkg/noun/trace.h
+++ b/pkg/noun/trace.h
@@ -103,7 +103,7 @@
     /* u3t_trace_open(): opens the path for writing tracing information.
     */
       void
-      u3t_trace_open(c3_c *dir_c);
+      u3t_trace_open(const c3_c *dir_c);
 
     /* u3t_trace_close(): closes the trace file. optional.
     */
diff --git a/pkg/noun/v1/allocate.c b/pkg/noun/v1/allocate.c
new file mode 100644
index 0000000000..7ce4521ecc
--- /dev/null
+++ b/pkg/noun/v1/allocate.c
@@ -0,0 +1,238 @@
+/// @file
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/v1/allocate.h"
+
+#include "pkg/noun/v1/hashtable.h"
+
+/* _box_v1_slot(): select the right free list to search for a block.
+*/
+static c3_w
+_box_v1_slot(c3_w siz_w)
+{
+  if ( siz_w < u3a_v1_minimum ) {
+    return 0;
+  }
+  else {
+    c3_w i_w = 1;
+
+    while ( 1 ) {
+      if ( i_w == u3a_v1_fbox_no ) {
+        return (i_w - 1);
+      }
+      if ( siz_w < 16 ) {
+        return i_w;
+      }
+      siz_w = (siz_w + 1) >> 1;
+      i_w += 1;
+    }
+  }
+}
+
+/* _box_v1_make(): construct a box.
+*/
+static u3a_v1_box*
+_box_v1_make(void* box_v, c3_w siz_w, c3_w use_w)
+{
+  u3a_v1_box* box_u = box_v;
+  c3_w*    box_w = box_v;
+
+  u3_assert(siz_w >= u3a_v1_minimum);
+
+  box_w[0] = siz_w;
+  box_w[siz_w - 1] = siz_w;
+  box_u->use_w = use_w;
+
+# ifdef  U3_MEMORY_DEBUG
+    box_u->cod_w = u3_Code;
+    box_u->eus_w = 0;
+# endif
+
+  return box_u;
+}
+
+/* _box_v1_attach(): attach a box to the free list.
+*/
+static void
+_box_v1_attach(u3a_v1_box* box_u)
+{
+  u3_assert(box_u->siz_w >= (1 + c3_wiseof(u3a_v1_fbox)));
+  u3_assert(0 != u3of(u3a_v1_fbox, box_u));
+
+  {
+    c3_w           sel_w = _box_v1_slot(box_u->siz_w);
+    u3p(u3a_v1_fbox)  fre_p = u3of(u3a_v1_fbox, box_u);
+    u3p(u3a_v1_fbox)* pfr_p = &u3R_v1->all.fre_p[sel_w];
+    u3p(u3a_v1_fbox)  nex_p = *pfr_p;
+
+    u3to(u3a_v1_fbox, fre_p)->pre_p = 0;
+    u3to(u3a_v1_fbox, fre_p)->nex_p = nex_p;
+    if ( u3to(u3a_v1_fbox, fre_p)->nex_p ) {
+      u3to(u3a_v1_fbox, u3to(u3a_v1_fbox, fre_p)->nex_p)->pre_p = fre_p;
+    }
+    (*pfr_p) = fre_p;
+  }
+}
+
+/* _box_v1_detach(): detach a box from the free list.
+*/
+static void
+_box_v1_detach(u3a_v1_box* box_u)
+{
+  u3p(u3a_v1_fbox) fre_p = u3of(u3a_v1_fbox, box_u);
+  u3p(u3a_v1_fbox) pre_p = u3to(u3a_v1_fbox, fre_p)->pre_p;
+  u3p(u3a_v1_fbox) nex_p = u3to(u3a_v1_fbox, fre_p)->nex_p;
+
+
+  if ( nex_p ) {
+    if ( u3to(u3a_v1_fbox, nex_p)->pre_p != fre_p ) {
+      u3_assert(!"loom: corrupt");
+    }
+    u3to(u3a_v1_fbox, nex_p)->pre_p = pre_p;
+  }
+  if ( pre_p ) {
+    if( u3to(u3a_v1_fbox, pre_p)->nex_p != fre_p ) {
+      u3_assert(!"loom: corrupt");
+    }
+    u3to(u3a_v1_fbox, pre_p)->nex_p = nex_p;
+  }
+  else {
+    c3_w sel_w = _box_v1_slot(box_u->siz_w);
+
+    if ( fre_p != u3R_v1->all.fre_p[sel_w] ) {
+      u3_assert(!"loom: corrupt");
+    }
+    u3R_v1->all.fre_p[sel_w] = nex_p;
+  }
+}
+
+/* _box_v1_free(): free and coalesce.
+*/
+static void
+_box_v1_free(u3a_v1_box* box_u)
+{
+  c3_w* box_w = (c3_w *)(void *)box_u;
+
+  u3_assert(box_u->use_w != 0);
+  box_u->use_w -= 1;
+  if ( 0 != box_u->use_w ) {
+    return;
+  }
+
+  //  we're always migrating a north road, so no need to check for it
+  {
+    /* Try to coalesce with the block below.
+    */
+    if ( box_w != u3a_v1_into(u3R_v1->rut_p) ) {
+      c3_w       laz_w = *(box_w - 1);
+      u3a_v1_box* pox_u = (u3a_v1_box*)(void *)(box_w - laz_w);
+
+      if ( 0 == pox_u->use_w ) {
+        _box_v1_detach(pox_u);
+        _box_v1_make(pox_u, (laz_w + box_u->siz_w), 0);
+
+        box_u = pox_u;
+        box_w = (c3_w*)(void *)pox_u;
+      }
+    }
+
+    /* Try to coalesce with the block above, or the wilderness.
+    */
+    if ( (box_w + box_u->siz_w) == u3a_v1_into(u3R_v1->hat_p) ) {
+      u3R_v1->hat_p = u3a_v1_outa(box_w);
+    }
+    else {
+      u3a_v1_box* nox_u = (u3a_v1_box*)(void *)(box_w + box_u->siz_w);
+
+      if ( 0 == nox_u->use_w ) {
+        _box_v1_detach(nox_u);
+        _box_v1_make(box_u, (box_u->siz_w + nox_u->siz_w), 0);
+      }
+      _box_v1_attach(box_u);
+    }
+  }
+}
+
+/* u3a_v1_wfree(): free storage.
+*/
+void
+u3a_v1_wfree(void* tox_v)
+{
+  _box_v1_free(u3a_v1_botox(tox_v));
+}
+
+/* u3a_v1_free(): free for aligned malloc.
+*/
+void
+u3a_v1_free(void* tox_v)
+{
+  if (NULL == tox_v)
+    return;
+
+  c3_w* tox_w = tox_v;
+  c3_w  pad_w = tox_w[-1];
+  c3_w* org_w = tox_w - (pad_w + 1);
+
+  // u3l_log("free %p %p", org_w, tox_w);
+  u3a_v1_wfree(org_w);
+}
+
+/* u3a_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+*/
+void
+u3a_v1_reclaim(void)
+{
+  //  clear the memoization cache
+  //
+  u3h_v1_free_nodes(u3R_v1->cax.har_p);
+}
+
+/* _me_v1_lose_north(): lose on a north road.
+*/
+static void
+_me_v1_lose_north(u3_noun dog)
+{
+top:
+  {
+    c3_w* dog_w      = u3a_v1_to_ptr(dog);
+    u3a_v1_box* box_u = u3a_v1_botox(dog_w);
+
+    if ( box_u->use_w > 1 ) {
+      box_u->use_w -= 1;
+    }
+    else {
+      if ( 0 == box_u->use_w ) {
+        u3m_v1_bail(c3__foul);
+      }
+      else {
+        if ( _(u3a_v1_is_pom(dog)) ) {
+          u3a_v1_cell* dog_u = (void *)dog_w;
+          u3_noun     h_dog = dog_u->hed;
+          u3_noun     t_dog = dog_u->tel;
+
+          if ( !_(u3a_v1_is_cat(h_dog)) ) {
+            _me_v1_lose_north(h_dog);
+          }
+          u3a_v1_wfree(dog_w);
+          if ( !_(u3a_v1_is_cat(t_dog)) ) {
+            dog = t_dog;
+            goto top;
+          }
+        }
+        else {
+          u3a_v1_wfree(dog_w);
+        }
+      }
+    }
+  }
+}
+
+/* u3a_v1_lose(): lose a reference count.
+*/
+void
+u3a_v1_lose(u3_noun som)
+{
+  if ( !_(u3a_v1_is_cat(som)) ) {
+    _me_v1_lose_north(som);
+  }
+}
diff --git a/pkg/noun/v1/allocate.h b/pkg/noun/v1/allocate.h
new file mode 100644
index 0000000000..4544417b78
--- /dev/null
+++ b/pkg/noun/v1/allocate.h
@@ -0,0 +1,78 @@
+#ifndef U3_ALLOCATE_V1_H
+#define U3_ALLOCATE_V1_H
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/v2/allocate.h"
+
+  /**  Aliases.
+  **/
+#     define u3R_v1           u3R_v2
+#     define u3a_v1_botox     u3a_v2_botox
+#     define u3a_v1_box       u3a_v2_box
+#     define u3a_v1_cell      u3a_v2_cell
+#     define u3a_v1_fbox      u3a_v2_fbox
+#     define u3a_v1_fbox_no   u3a_v2_fbox_no
+#     define u3a_v1_into      u3a_v2_into
+#     define u3a_v1_is_cat    u3a_v2_is_cat
+#     define u3a_v1_is_north  u3a_v2_is_north
+#     define u3a_v1_is_pom    u3a_v2_is_pom
+#     define u3a_v1_minimum   u3a_v2_minimum
+#     define u3a_v1_outa      u3a_v2_outa
+
+  /**  Structures.
+  **/
+  /**  Macros.  Should be better commented.
+  **/
+    /* Inside a noun.
+    */
+    /* u3a_v1_to_off(): mask off bits 30 and 31 from noun [som].
+    */
+#     define u3a_v1_to_off(som)    ((som) & 0x3fffffff)
+
+    /* u3a_v1_to_ptr(): convert noun [som] into generic pointer into loom.
+    */
+#     define u3a_v1_to_ptr(som)    (u3a_v1_into(u3a_v1_to_off(som)))
+
+    /* u3a_v1_to_wtr(): convert noun [som] into word pointer into loom.
+    */
+#     define u3a_v1_to_wtr(som)    ((c3_w *)u3a_v1_to_ptr(som))
+
+    /* u3a_v1_to_pug(): set bit 31 of [off].
+    */
+#     define u3a_v1_to_pug(off)    (off | 0x80000000)
+
+    /* u3a_v1_to_pom(): set bits 30 and 31 of [off].
+    */
+#     define u3a_v1_to_pom(off)    (off | 0xc0000000)
+
+  /**  Functions.
+  **/
+    /**  Allocation.
+    **/
+      /* Word-aligned allocation.
+      */
+        /* u3a_v1_wfree(): free storage.
+        */
+          void
+          u3a_v1_wfree(void* lag_v);
+
+      /* C-style aligned allocation - *not* compatible with above.
+      */
+        /* u3a_v1_free(): free for aligned malloc.
+        */
+          void
+          u3a_v1_free(void* tox_v);
+
+      /* Reference and arena control.
+      */
+        /* u3a_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+        */
+          void
+          u3a_v1_reclaim(void);
+
+        /* u3a_v1_lose(): lose a reference count.
+        */
+          void
+          u3a_v1_lose(u3_noun som);
+
+#endif /* ifndef U3_ALLOCATE_H */
diff --git a/pkg/noun/v1/hashtable.c b/pkg/noun/v1/hashtable.c
new file mode 100644
index 0000000000..aa3a9b7aef
--- /dev/null
+++ b/pkg/noun/v1/hashtable.c
@@ -0,0 +1,173 @@
+/// @file
+
+#include "pkg/noun/hashtable.h"
+#include "pkg/noun/v1/hashtable.h"
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/v1/allocate.h"
+
+
+/* _ch_v1_popcount(): number of bits set in word.  A standard intrinsic.
+**             NB: copy of _ch_v1_popcount in pkg/noun/hashtable.c
+*/
+static c3_w
+_ch_v1_popcount(c3_w num_w)
+{
+  return __builtin_popcount(num_w);
+}
+
+/* _ch_v1_free_buck(): free bucket
+**              NB: copy of _ch_v1_free_buck in pkg/noun/hashtable.c
+*/
+static void
+_ch_v1_free_buck(u3h_v1_buck* hab_u)
+{
+  c3_w i_w;
+
+  for ( i_w = 0; i_w < hab_u->len_w; i_w++ ) {
+    u3a_v1_lose(u3h_v1_slot_to_noun(hab_u->sot_w[i_w]));
+  }
+  u3a_v1_wfree(hab_u);
+}
+
+/* _ch_v1_free_node(): free node.
+*/
+static void
+_ch_v1_free_node(u3h_v1_node* han_u, c3_w lef_w)
+{
+  c3_w len_w = _ch_v1_popcount(han_u->map_w);
+  c3_w i_w;
+
+  lef_w -= 5;
+
+  for ( i_w = 0; i_w < len_w; i_w++ ) {
+    c3_w sot_w = han_u->sot_w[i_w];
+
+    if ( _(u3h_v1_slot_is_noun(sot_w)) ) {
+      u3a_v1_lose(u3h_v1_slot_to_noun(sot_w));
+    }
+    else {
+      void* hav_v = u3h_v1_slot_to_node(sot_w);
+
+      if ( 0 == lef_w ) {
+        _ch_v1_free_buck(hav_v);
+      } else {
+        _ch_v1_free_node(hav_v, lef_w);
+      }
+    }
+  }
+  u3a_v1_wfree(han_u);
+}
+
+/* u3h_v1_free_nodes(): free hashtable nodes.
+*/
+void
+u3h_v1_free_nodes(u3p(u3h_v1_root) har_p)
+{
+  u3h_v1_root* har_u = u3to(u3h_v1_root, har_p);
+  c3_w        i_w;
+
+  for ( i_w = 0; i_w < 64; i_w++ ) {
+    c3_w sot_w = har_u->sot_w[i_w];
+
+    if ( _(u3h_v1_slot_is_noun(sot_w)) ) {
+      u3a_v1_lose(u3h_v1_slot_to_noun(sot_w));
+    }
+    else if ( _(u3h_v1_slot_is_node(sot_w)) ) {
+      u3h_v1_node* han_u = (u3h_v1_node*) u3h_v1_slot_to_node(sot_w);
+
+      _ch_v1_free_node(han_u, 25);
+    }
+    har_u->sot_w[i_w] = 0;
+  }
+  har_u->use_w       = 0;
+  har_u->arm_u.mug_w = 0;
+  har_u->arm_u.inx_w = 0;
+}
+
+/* _ch_v1_walk_buck(): walk bucket for gc.
+**              NB: copy of _ch_v1_walk_buck in pkg/noun/hashtable.c
+*/
+static void
+_ch_v1_walk_buck(u3h_v1_buck* hab_u, void (*fun_f)(u3_noun, void*), void* wit)
+{
+  c3_w i_w;
+
+  for ( i_w = 0; i_w < hab_u->len_w; i_w++ ) {
+    fun_f(u3h_v1_slot_to_noun(hab_u->sot_w[i_w]), wit);
+  }
+}
+
+/* _ch_v1_walk_node(): walk node for gc.
+*/
+static void
+_ch_v1_walk_node(u3h_v1_node* han_u, c3_w lef_w, void (*fun_f)(u3_noun, void*), void* wit)
+{
+  c3_w len_w = _ch_v1_popcount(han_u->map_w);
+  c3_w i_w;
+
+  lef_w -= 5;
+
+  for ( i_w = 0; i_w < len_w; i_w++ ) {
+    c3_w sot_w = han_u->sot_w[i_w];
+
+    if ( _(u3h_v1_slot_is_noun(sot_w)) ) {
+      u3_noun kev = u3h_v1_slot_to_noun(sot_w);
+
+      fun_f(kev, wit);
+    }
+    else {
+      void* hav_v = u3h_v1_slot_to_node(sot_w);
+
+      if ( 0 == lef_w ) {
+        _ch_v1_walk_buck(hav_v, fun_f, wit);
+      } else {
+        _ch_v1_walk_node(hav_v, lef_w, fun_f, wit);
+      }
+    }
+  }
+}
+
+/* u3h_v1_walk_with(): traverse hashtable with key, value fn and data
+ *                  argument; RETAINS.
+*/
+void
+u3h_v1_walk_with(u3p(u3h_v1_root) har_p,
+              void (*fun_f)(u3_noun, void*),
+              void* wit)
+{
+  u3h_v1_root* har_u = u3to(u3h_v1_root, har_p);
+  c3_w        i_w;
+
+  for ( i_w = 0; i_w < 64; i_w++ ) {
+    c3_w sot_w = har_u->sot_w[i_w];
+
+    if ( _(u3h_v1_slot_is_noun(sot_w)) ) {
+      u3_noun kev = u3h_v1_slot_to_noun(sot_w);
+
+      fun_f(kev, wit);
+    }
+    else if ( _(u3h_v1_slot_is_node(sot_w)) ) {
+      u3h_v1_node* han_u = (u3h_v1_node*) u3h_v1_slot_to_node(sot_w);
+
+      _ch_v1_walk_node(han_u, 25, fun_f, wit);
+    }
+  }
+}
+
+/* _ch_v1_walk_plain(): use plain u3_noun fun_f for each node
+ */
+static void
+_ch_v1_walk_plain(u3_noun kev, void* wit)
+{
+  void (*fun_f)(u3_noun) = wit;
+  fun_f(kev);
+}
+
+/* u3h_v1_walk(): u3h_v1_walk_with, but with no data argument
+*/
+void
+u3h_v1_walk(u3p(u3h_v1_root) har_p, void (*fun_f)(u3_noun))
+{
+  u3h_v1_walk_with(har_p, _ch_v1_walk_plain, fun_f);
+}
diff --git a/pkg/noun/v1/hashtable.h b/pkg/noun/v1/hashtable.h
new file mode 100644
index 0000000000..2d5fdea6f3
--- /dev/null
+++ b/pkg/noun/v1/hashtable.h
@@ -0,0 +1,51 @@
+#ifndef U3_HASHTABLE_V1_H
+#define U3_HASHTABLE_V1_H
+
+#include "pkg/noun/hashtable.h"
+#include "pkg/noun/v2/hashtable.h"
+
+  /**  Aliases.
+  **/
+#     define  u3h_v1_buck          u3h_v2_buck
+#     define  u3h_v1_node          u3h_v2_node
+#     define  u3h_v1_root          u3h_v2_root
+#     define  u3h_v1_slot_is_node  u3h_v2_slot_is_node
+#     define  u3h_v1_slot_is_noun  u3h_v2_slot_is_noun
+#     define  u3h_v1_slot_to_noun  u3h_v2_slot_to_noun
+
+  /**  Data structures.
+  **/
+
+    /**  HAMT macros.
+    ***
+    ***  Coordinate with u3_noun definition!
+    **/
+      /* u3h_v1_slot_to_node(): slot to node pointer
+      ** u3h_v1_node_to_slot(): node pointer to slot
+      */
+#     define  u3h_v1_slot_to_node(sot)  (u3a_v1_into((sot) & 0x3fffffff))
+#     define  u3h_v1_node_to_slot(ptr)  (u3a_v1_outa(ptr) | 0x40000000)
+
+    /**  Functions.
+    ***
+    ***  Needs: delete and merge functions; clock reclamation function.
+    **/
+      /* u3h_v1_free(): free hashtable.
+      */
+        void
+        u3h_v1_free_nodes(u3p(u3h_root) har_p);
+
+      /* u3h_v1_walk_with(): traverse hashtable with key, value fn and data
+       *                  argument; RETAINS.
+      */
+        void
+        u3h_v1_walk_with(u3p(u3h_root) har_p,
+                      void (*fun_f)(u3_noun, void*),
+                      void* wit);
+
+      /* u3h_v1_walk(): u3h_v1_walk_with, but with no data argument
+      */
+        void
+        u3h_v1_walk(u3p(u3h_root) har_p, void (*fun_f)(u3_noun));
+
+#endif /* ifndef U3_HASHTABLE_H */
diff --git a/pkg/noun/v1/jets.c b/pkg/noun/v1/jets.c
new file mode 100644
index 0000000000..272930e11d
--- /dev/null
+++ b/pkg/noun/v1/jets.c
@@ -0,0 +1,87 @@
+/// @file
+
+#include "pkg/noun/vortex.h"
+
+#include "pkg/noun/jets.h"
+#include "pkg/noun/v1/jets.h"
+#include "pkg/noun/v2/jets.h"
+
+#include "pkg/noun/v1/allocate.h"
+#include "pkg/noun/v1/hashtable.h"
+
+
+/* _cj_fink_free(): lose and free everything in a u3j_v1_fink.
+*/
+static void
+_cj_v1_fink_free(u3p(u3j_v1_fink) fin_p)
+{
+  c3_w i_w;
+  u3j_v1_fink* fin_u = u3to(u3j_v1_fink, fin_p);
+  u3a_v1_lose(fin_u->sat);
+  for ( i_w = 0; i_w < fin_u->len_w; ++i_w ) {
+    u3j_v1_fist* fis_u = &(fin_u->fis_u[i_w]);
+    u3a_v1_lose(fis_u->bat);
+    u3a_v1_lose(fis_u->pax);
+  }
+  u3a_v1_wfree(fin_u);
+}
+
+/* u3j_v1_rite_lose(): lose references of u3j_v1_rite (but do not free).
+ */
+void
+u3j_v1_rite_lose(u3j_v1_rite* rit_u)
+{
+  if ( (c3y == rit_u->own_o) && u3_none != rit_u->clu ) {
+    u3a_v1_lose(rit_u->clu);
+    _cj_v1_fink_free(rit_u->fin_p);
+  }
+}
+
+
+/* u3j_v1_site_lose(): lose references of u3j_v1_site (but do not free).
+ */
+void
+u3j_v1_site_lose(u3j_v1_site* sit_u)
+{
+  u3a_v1_lose(sit_u->axe);
+  if ( u3_none != sit_u->bat ) {
+    u3a_v1_lose(sit_u->bat);
+  }
+  if ( u3_none != sit_u->bas ) {
+    u3a_v1_lose(sit_u->bas);
+  }
+  if ( u3_none != sit_u->loc ) {
+    u3a_v1_lose(sit_u->loc);
+    u3a_v1_lose(sit_u->lab);
+    if ( c3y == sit_u->fon_o ) {
+      if ( sit_u->fin_p ) {
+      _cj_v1_fink_free(sit_u->fin_p);
+      }
+    }
+  }
+}
+
+/* _cj_v1_free_hank(): free an entry from the hank cache.
+*/
+static void
+_cj_v1_free_hank(u3_noun kev)
+{
+  u3a_v1_cell* cel_u = (u3a_v1_cell*) u3a_v1_to_ptr(kev);
+  u3j_v1_hank* han_u = u3to(u3j_v1_hank, cel_u->tel);
+  if ( u3_none != han_u->hax ) {
+    u3a_v1_lose(han_u->hax);
+    u3j_v1_site_lose(&(han_u->sit_u));
+  }
+  u3a_v1_wfree(han_u);
+}
+
+/* u3j_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+*/
+void
+u3j_v1_reclaim(void)
+{
+  //  clear the jet hank cache
+  //
+  u3h_v1_walk(u3R_v1->jed.han_p, _cj_v1_free_hank);
+  u3h_v1_free_nodes(u3R_v1->jed.han_p);
+}
diff --git a/pkg/noun/v1/jets.h b/pkg/noun/v1/jets.h
new file mode 100644
index 0000000000..bf3dfe6afe
--- /dev/null
+++ b/pkg/noun/v1/jets.h
@@ -0,0 +1,34 @@
+/// @file
+
+#ifndef U3_JETS_V1_H
+#define U3_JETS_V1_H
+
+#include "pkg/noun/jets.h"
+#include "pkg/noun/v2/jets.h"
+
+  /**  Aliases.
+  **/
+#     define u3j_v1_fink       u3j_v2_fink
+#     define u3j_v1_fist       u3j_v2_fist
+#     define u3j_v1_hank       u3j_v2_hank
+#     define u3j_v1_rite       u3j_v2_rite
+#     define u3j_v1_site       u3j_v2_site
+
+  /**  Functions.
+  **/
+    /* u3j_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+    */
+      void
+      u3j_v1_reclaim(void);
+
+    /* u3j_v1_rite_lose(): lose references of u3j_rite (but do not free).
+    */
+      void
+      u3j_v1_rite_lose(u3j_v1_rite* rit_u);
+
+    /* u3j_v1_site_lose(): lose references of u3j_site (but do not free).
+    */
+      void
+      u3j_v1_site_lose(u3j_v1_site* sit_u);
+
+#endif /* ifndef U3_JETS_V1_H */
diff --git a/pkg/noun/v1/manage.c b/pkg/noun/v1/manage.c
new file mode 100644
index 0000000000..0eac6a8d7b
--- /dev/null
+++ b/pkg/noun/v1/manage.c
@@ -0,0 +1,20 @@
+/// @file
+
+#include "pkg/noun/v1/manage.h"
+
+#include "pkg/noun/v1/allocate.h"
+#include "pkg/noun/v1/hashtable.h"
+#include "pkg/noun/v1/jets.h"
+#include "pkg/noun/v1/nock.h"
+#include "pkg/noun/v1/vortex.h"
+
+/* u3m_v1_reclaim: clear persistent caches to reclaim memory
+*/
+void
+u3m_v1_reclaim(void)
+{
+  u3v_v1_reclaim();
+  u3j_v1_reclaim();
+  u3n_v1_reclaim();
+  u3a_v1_reclaim();
+}
diff --git a/pkg/noun/v1/manage.h b/pkg/noun/v1/manage.h
new file mode 100644
index 0000000000..669d69ea36
--- /dev/null
+++ b/pkg/noun/v1/manage.h
@@ -0,0 +1,17 @@
+/// @file
+
+#ifndef U3_MANAGE_V1_H
+#define U3_MANAGE_V1_H
+
+    /** Aliases.
+    **/
+#     define  u3m_v1_bail  u3m_bail
+
+    /** System management.
+    **/
+      /* u3m_v1_reclaim: clear persistent caches to reclaim memory
+      */
+        void
+        u3m_v1_reclaim(void);
+
+#endif /* ifndef U3_MANAGE_V1_H */
diff --git a/pkg/noun/v1/nock.c b/pkg/noun/v1/nock.c
new file mode 100644
index 0000000000..1ac2931a97
--- /dev/null
+++ b/pkg/noun/v1/nock.c
@@ -0,0 +1,69 @@
+/// @file
+
+#include "pkg/noun/nock.h"
+#include "pkg/noun/v1/nock.h"
+
+#include "pkg/noun/v1/allocate.h"
+#include "pkg/noun/v1/hashtable.h"
+#include "pkg/noun/jets.h"
+#include "pkg/noun/v1/jets.h"
+
+/* u3n_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+*/
+void
+u3n_v1_reclaim(void)
+{
+  //  clear the bytecode cache
+  //
+  //    We can't just u3h_v1_free() -- the value is a post to a u3n_v1_prog.
+  //    Note that the hank cache *must* also be freed (in u3j_v1_reclaim())
+  //
+  u3n_v1_free();
+}
+
+/* _cn_v1_prog_free(): free memory retained by program pog_u
+*/
+static void
+_cn_v1_prog_free(u3n_v1_prog* pog_u)
+{
+  // fix up pointers for loom portability
+  pog_u->byc_u.ops_y = (c3_y*) ((void*) pog_u) + sizeof(u3n_v1_prog);
+  pog_u->lit_u.non   = (u3_noun*) (pog_u->byc_u.ops_y + pog_u->byc_u.len_w);
+  pog_u->mem_u.sot_u = (u3n_v1_memo*) (pog_u->lit_u.non + pog_u->lit_u.len_w);
+  pog_u->cal_u.sit_u = (u3j_v1_site*) (pog_u->mem_u.sot_u + pog_u->mem_u.len_w);
+  pog_u->reg_u.rit_u = (u3j_v1_rite*) (pog_u->cal_u.sit_u + pog_u->cal_u.len_w);
+
+  c3_w dex_w;
+  for (dex_w = 0; dex_w < pog_u->lit_u.len_w; ++dex_w) {
+    u3a_v1_lose(pog_u->lit_u.non[dex_w]);
+  }
+  for (dex_w = 0; dex_w < pog_u->mem_u.len_w; ++dex_w) {
+    u3a_v1_lose(pog_u->mem_u.sot_u[dex_w].key);
+  }
+  for (dex_w = 0; dex_w < pog_u->cal_u.len_w; ++dex_w) {
+    u3j_v1_site_lose(&(pog_u->cal_u.sit_u[dex_w]));
+  }
+  for (dex_w = 0; dex_w < pog_u->reg_u.len_w; ++dex_w) {
+    u3j_v1_rite_lose(&(pog_u->reg_u.rit_u[dex_w]));
+  }
+  u3a_v1_free(pog_u);
+}
+
+/* _n_v1_feb(): u3h_v1_walk helper for u3n_v1_free
+ */
+static void
+_n_v1_feb(u3_noun kev)
+{
+  u3a_v1_cell *cel_u = (u3a_v1_cell*) u3a_v1_to_ptr(kev);
+  _cn_v1_prog_free(u3to(u3n_v1_prog, cel_u->tel));
+}
+
+/* u3n_v1_free(): free bytecode cache
+ */
+void
+u3n_v1_free()
+{
+  u3p(u3h_v1_root) har_p = u3R_v1->byc.har_p;
+  u3h_v1_walk(har_p, _n_v1_feb);
+  u3h_v1_free_nodes(har_p);
+}
diff --git a/pkg/noun/v1/nock.h b/pkg/noun/v1/nock.h
new file mode 100644
index 0000000000..5320307b6b
--- /dev/null
+++ b/pkg/noun/v1/nock.h
@@ -0,0 +1,25 @@
+/// @file
+
+#ifndef U3_NOCK_V1_H
+#define U3_NOCK_V1_H
+
+#include "pkg/noun/v2/nock.h"
+
+  /**  Aliases.
+  **/
+#     define  u3n_v1_memo  u3n_v2_memo
+#     define  u3n_v1_prog  u3n_v2_prog
+
+  /**  Functions.
+  **/
+    /* u3n_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+    */
+      void
+      u3n_v1_reclaim(void);
+
+    /* u3n_v1_free(): free bytecode cache.
+     */
+      void
+      u3n_v1_free(void);
+
+#endif /* ifndef U3_NOCK_V1_H */
diff --git a/pkg/noun/v1/vortex.c b/pkg/noun/v1/vortex.c
new file mode 100644
index 0000000000..e1ec21b22d
--- /dev/null
+++ b/pkg/noun/v1/vortex.c
@@ -0,0 +1,17 @@
+/// @file
+
+#include "pkg/noun/vortex.h"
+#include "pkg/noun/v1/vortex.h"
+
+#include "pkg/noun/v1/allocate.h"
+
+/* u3v_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+*/
+void
+u3v_v1_reclaim(void)
+{
+  //  clear the u3v_wish cache
+  //
+  u3a_v1_lose(u3A_v1->yot);
+  u3A_v1->yot = u3_nul;
+}
diff --git a/pkg/noun/v1/vortex.h b/pkg/noun/v1/vortex.h
new file mode 100644
index 0000000000..84cf6e405c
--- /dev/null
+++ b/pkg/noun/v1/vortex.h
@@ -0,0 +1,22 @@
+/// @file
+
+#ifndef U3_VORTEX_V1_H
+#define U3_VORTEX_V1_H
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/v2/vortex.h"
+
+  /**  Aliases.
+  **/
+#     define  u3H_v1       u3H_v2
+#     define  u3A_v1       u3A_v2
+#     define  u3v_v1_home  u3v_v2_home
+
+  /**  Functions.
+  **/
+    /* u3v_v1_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+    */
+      void
+      u3v_v1_reclaim(void);
+
+#endif /* ifndef U3_VORTEX_V1_H */
diff --git a/pkg/noun/v2/allocate.c b/pkg/noun/v2/allocate.c
new file mode 100644
index 0000000000..25cf04a948
--- /dev/null
+++ b/pkg/noun/v2/allocate.c
@@ -0,0 +1,73 @@
+/// @file
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/v1/allocate.h"
+#include "pkg/noun/v2/allocate.h"
+
+#include "pkg/noun/v2/hashtable.h"
+#include "log.h"
+#include "pkg/noun/v2/manage.h"
+#include "options.h"
+#include "retrieve.h"
+#include "trace.h"
+#include "vortex.h"
+
+u3a_v2_road* u3a_v2_Road;
+
+u3_noun
+u3a_v2_rewritten_noun(u3_noun som)
+{
+  if ( c3y == u3a_v2_is_cat(som) ) {
+    return som;
+  }
+  u3_post som_p = u3a_v2_rewritten(u3a_v1_to_off(som));
+
+  if ( c3y == u3a_v2_is_pug(som) ) {
+    som_p = u3a_v2_to_pug(som_p);
+  }
+  else {
+    som_p = u3a_v2_to_pom(som_p);
+  }
+
+  return som_p;
+}
+
+/* u3a_v2_mig_rewrite_compact(): rewrite pointers in ad-hoc persistent road structures.
+*/
+void
+u3a_v2_mig_rewrite_compact(void)
+{
+  u3a_v2_rewrite_noun(u3R_v2->ski.gul);
+  u3a_v2_rewrite_noun(u3R_v2->bug.tax);
+  u3a_v2_rewrite_noun(u3R_v2->bug.mer);
+  u3a_v2_rewrite_noun(u3R_v2->pro.don);
+  u3a_v2_rewrite_noun(u3R_v2->pro.day);
+  u3a_v2_rewrite_noun(u3R_v2->pro.trace);
+  u3h_v2_rewrite(u3R_v2->cax.har_p);
+
+  u3R_v2->ski.gul = u3a_v2_rewritten_noun(u3R_v2->ski.gul);
+  u3R_v2->bug.tax = u3a_v2_rewritten_noun(u3R_v2->bug.tax);
+  u3R_v2->bug.mer = u3a_v2_rewritten_noun(u3R_v2->bug.mer);
+  u3R_v2->pro.don = u3a_v2_rewritten_noun(u3R_v2->pro.don);
+  u3R_v2->pro.day = u3a_v2_rewritten_noun(u3R_v2->pro.day);
+  u3R_v2->pro.trace = u3a_v2_rewritten_noun(u3R_v2->pro.trace);
+  u3R_v2->cax.har_p = u3a_v2_rewritten(u3R_v2->cax.har_p);
+}
+
+void
+u3a_v2_rewrite_noun(u3_noun som)
+{
+  if ( c3n == u3a_v2_is_cell(som) ) {
+    return;
+  }
+
+  if ( c3n == u3a_v2_rewrite_ptr(u3a_v1_to_ptr((som))) ) return;
+
+  u3a_v2_cell* cel = (u3a_v2_cell*) u3a_v1_to_ptr(som);
+
+  u3a_v2_rewrite_noun(cel->hed);
+  u3a_v2_rewrite_noun(cel->tel);
+
+  cel->hed = u3a_v2_rewritten_noun(cel->hed);
+  cel->tel = u3a_v2_rewritten_noun(cel->tel);
+}
diff --git a/pkg/noun/v2/allocate.h b/pkg/noun/v2/allocate.h
new file mode 100644
index 0000000000..1f191795fc
--- /dev/null
+++ b/pkg/noun/v2/allocate.h
@@ -0,0 +1,134 @@
+#ifndef U3_ALLOCATE_V2_H
+#define U3_ALLOCATE_V2_H
+
+#include "pkg/noun/allocate.h"
+
+#include "pkg/noun/v2/manage.h"
+#include "options.h"
+
+  /**  Aliases.
+  **/
+#     define u3a_v2_botox        u3a_botox
+#     define u3a_v2_box          u3a_box
+#     define u3a_v2_cell         u3a_cell
+#     define u3a_v2_fbox         u3a_fbox
+#     define u3a_v2_fbox_no      u3a_fbox_no
+#     define u3a_v2_free         u3a_free
+#     define u3a_v2_heap         u3a_heap
+#     define u3a_v2_into         u3a_into
+#     define u3a_v2_is_cat       u3a_is_cat
+#     define u3a_v2_is_cell      u3a_is_cell
+#     define u3a_v2_is_north     u3a_is_north
+#     define u3a_v2_is_pom       u3a_is_pom
+#     define u3a_v2_is_pug       u3a_is_pug
+#     define u3a_v2_lose         u3a_lose
+#     define u3a_v2_malloc       u3a_malloc
+#     define u3a_v2_minimum      u3a_minimum
+#     define u3a_v2_outa         u3a_outa
+#     define u3a_v2_pack_seek    u3a_pack_seek
+#     define u3a_v2_rewrite      u3a_rewrite
+#     define u3a_v2_rewrite_ptr  u3a_rewrite_ptr
+#     define u3a_v2_rewritten    u3a_rewritten
+#     define u3a_v2_to_off       u3a_to_off
+#     define u3a_v2_to_ptr       u3a_to_ptr
+#     define u3a_v2_to_wtr       u3a_to_wtr
+#     define u3a_v2_to_pug       u3a_to_pug
+#     define u3a_v2_to_pom       u3a_to_pom
+#     define u3a_v2_wfree        u3a_wfree
+
+  /**  Data structures.
+  **/
+    /* u3a_v2_road: contiguous allocation and execution context.
+    */
+      typedef struct _u3a_v2_road {
+        u3p(struct _u3a_v2_road) par_p;          //  parent road
+        u3p(struct _u3a_v2_road) kid_p;          //  child road list
+        u3p(struct _u3a_v2_road) nex_p;          //  sibling road
+
+        u3p(c3_w) cap_p;                      //  top of transient region
+        u3p(c3_w) hat_p;                      //  top of durable region
+        u3p(c3_w) mat_p;                      //  bottom of transient region
+        u3p(c3_w) rut_p;                      //  bottom of durable region
+        u3p(c3_w) ear_p;                      //  original cap if kid is live
+
+        c3_w fut_w[32];                       //  futureproof buffer
+
+        struct {                              //  escape buffer
+          union {
+            jmp_buf buf;
+            c3_w buf_w[256];                  //  futureproofing
+          };
+        } esc;
+
+        struct {                              //  miscellaneous config
+          c3_w fag_w;                         //  flag bits
+        } how;                                //
+
+        struct {                                   //  allocation pools
+          u3p(u3a_v2_fbox) fre_p[u3a_v2_fbox_no];  //  heap by node size log
+          u3p(u3a_fbox) cel_p;                //  custom cell allocator
+          c3_w fre_w;                         //  number of free words
+          c3_w max_w;                         //  maximum allocated
+        } all;
+
+        u3a_jets jed;                         //  jet dashboard
+
+        struct {                              // bytecode state
+          u3p(u3h_root) har_p;                // formula->post of bytecode
+        } byc;
+
+        struct {                              //  namespace
+          u3_noun gul;                        //  (list $+(* (unit (unit)))) now
+        } ski;
+
+        struct {                              //  trace stack
+          u3_noun tax;                        //  (list ,*)
+          u3_noun mer;                        //  emergency buffer to release
+        } bug;
+
+        struct {                              //  profile stack
+          c3_d    nox_d;                      //  nock steps
+          c3_d    cel_d;                      //  cell allocations
+          u3_noun don;                        //  (list batt)
+          u3_noun trace;                      //  (list trace)
+          u3_noun day;                        //  doss, only in u3H (moveme)
+        } pro;
+
+        struct {                              //  memoization
+          u3p(u3h_root) har_p;                //  (map (pair term noun) noun)
+        } cax;
+      } u3a_v2_road;
+
+  /**  Globals.
+  **/
+      /// Current road (thread-local).
+      extern u3a_v2_road* u3a_v2_Road;
+#       define u3R_v2  u3a_v2_Road
+
+  /**  Functions.
+  **/
+    /**  Allocation.
+    **/
+      /* Reference and arena control.
+      */
+        /* u3a_v2_mig_rewrite_compact(): rewrite pointers in ad-hoc persistent road structures.
+        */
+          void
+          u3a_v2_mig_rewrite_compact(void);
+
+        /* u3a_v2_rewrite_noun(): rewrite a noun for compaction.
+        */
+          void
+          u3a_v2_rewrite_noun(u3_noun som);
+
+        /* u3a_v2_rewritten(): rewrite a pointer for compaction.
+        */
+          u3_post
+          u3a_v2_rewritten(u3_post som_p);
+
+        /* u3a_v2_rewritten(): rewritten noun pointer for compaction.
+        */
+          u3_noun
+          u3a_v2_rewritten_noun(u3_noun som);
+
+#endif /* ifndef U3_ALLOCATE_V2_H */
diff --git a/pkg/noun/v2/hashtable.c b/pkg/noun/v2/hashtable.c
new file mode 100644
index 0000000000..6963d07fde
--- /dev/null
+++ b/pkg/noun/v2/hashtable.c
@@ -0,0 +1,143 @@
+/// @file
+
+#include "pkg/noun/hashtable.h"
+#include "pkg/noun/v1/hashtable.h"
+#include "pkg/noun/v2/hashtable.h"
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/v1/allocate.h"
+#include "pkg/noun/v2/allocate.h"
+
+/* _ch_v2_popcount(): number of bits set in word.  A standard intrinsic.
+**             NB: copy of _ch_v2_popcount in pkg/noun/hashtable.c
+*/
+static c3_w
+_ch_v2_popcount(c3_w num_w)
+{
+  return __builtin_popcount(num_w);
+}
+
+/* _ch_v2_free_buck(): free bucket
+**              NB: copy of _ch_v2_free_buck in pkg/noun/hashtable.c
+*/
+static void
+_ch_v2_free_buck(u3h_v2_buck* hab_u)
+{
+  c3_w i_w;
+
+  for ( i_w = 0; i_w < hab_u->len_w; i_w++ ) {
+    u3z(u3h_v2_slot_to_noun(hab_u->sot_w[i_w]));
+  }
+  u3a_v2_wfree(hab_u);
+}
+
+/* _ch_v2_free_node(): free node.
+*/
+static void
+_ch_v2_free_node(u3h_v2_node* han_u, c3_w lef_w)
+{
+  c3_w len_w = _ch_v2_popcount(han_u->map_w);
+  c3_w i_w;
+
+  lef_w -= 5;
+
+  for ( i_w = 0; i_w < len_w; i_w++ ) {
+    c3_w sot_w = han_u->sot_w[i_w];
+
+    if ( _(u3h_v2_slot_is_noun(sot_w)) ) {
+      u3z(u3h_v2_slot_to_noun(sot_w));
+    }
+    else {
+      //  NB: u3h_v2_slot_to_node()
+      void* hav_v = u3h_v2_slot_to_node(sot_w);
+
+      if ( 0 == lef_w ) {
+        _ch_v2_free_buck(hav_v);
+      } else {
+        _ch_v2_free_node(hav_v, lef_w);
+      }
+    }
+  }
+  u3a_v2_wfree(han_u);
+}
+
+/* _ch_v2_rewrite_buck(): rewrite buck for compaction.
+*/
+void
+_ch_v2_rewrite_buck(u3h_v2_buck* hab_u)
+{
+  if ( c3n == u3a_v2_rewrite_ptr(hab_u) ) return;
+  c3_w i_w;
+
+  for ( i_w = 0; i_w < hab_u->len_w; i_w++ ) {
+    u3_noun som = u3h_v2_slot_to_noun(hab_u->sot_w[i_w]);
+    hab_u->sot_w[i_w] = u3h_v2_noun_to_slot(u3a_v2_rewritten_noun(som));
+    u3a_v2_rewrite_noun(som);
+  }
+}
+
+/* _ch_v2_rewrite_node(): rewrite node for compaction.
+*/
+void
+_ch_v2_rewrite_node(u3h_v2_node* han_u, c3_w lef_w)
+{
+  if ( c3n == u3a_v2_rewrite_ptr(han_u) ) return;
+
+  c3_w len_w = _ch_v2_popcount(han_u->map_w);
+  c3_w i_w;
+
+  lef_w -= 5;
+
+  for ( i_w = 0; i_w < len_w; i_w++ ) {
+    c3_w sot_w = han_u->sot_w[i_w];
+
+    if ( _(u3h_v2_slot_is_noun(sot_w)) ) {
+      u3_noun kev = u3h_v2_slot_to_noun(sot_w);
+      han_u->sot_w[i_w] = u3h_v2_noun_to_slot(u3a_v2_rewritten_noun(kev));
+
+      u3a_v2_rewrite_noun(kev);
+    }
+    else {
+      void* hav_v = u3h_v1_slot_to_node(sot_w);
+      u3h_v2_node* nod_u = u3to(u3h_v2_node, u3a_v2_rewritten(u3of(u3h_v2_node,hav_v)));
+
+      han_u->sot_w[i_w] = u3h_v2_node_to_slot(nod_u);
+
+      if ( 0 == lef_w ) {
+        _ch_v2_rewrite_buck(hav_v);
+      } else {
+        _ch_v2_rewrite_node(hav_v, lef_w);
+      }
+    }
+  }
+}
+
+/* u3h_v2_rewrite(): rewrite pointers during compaction.
+*/
+void
+u3h_v2_rewrite(u3p(u3h_v2_root) har_p)
+{
+  u3h_v2_root* har_u = u3to(u3h_v2_root, har_p);
+  c3_w        i_w;
+
+  if ( c3n == u3a_v2_rewrite_ptr(har_u) ) return;
+
+  for ( i_w = 0; i_w < 64; i_w++ ) {
+    c3_w sot_w = har_u->sot_w[i_w];
+
+    if ( _(u3h_v2_slot_is_noun(sot_w)) ) {
+      u3_noun kev = u3h_v2_slot_to_noun(sot_w);
+      har_u->sot_w[i_w] = u3h_v2_noun_to_slot(u3a_v2_rewritten_noun(kev));
+
+      u3a_v2_rewrite_noun(kev);
+    }
+    else if ( _(u3h_v2_slot_is_node(sot_w)) ) {
+      u3h_v2_node* han_u = (u3h_v2_node*) u3h_v1_slot_to_node(sot_w);
+      u3h_v2_node* nod_u = u3to(u3h_v2_node, u3a_v2_rewritten(u3of(u3h_v2_node,han_u)));
+
+      har_u->sot_w[i_w] = u3h_v2_node_to_slot(nod_u);
+
+      _ch_v2_rewrite_node(han_u, 25);
+    }
+  }
+}
diff --git a/pkg/noun/v2/hashtable.h b/pkg/noun/v2/hashtable.h
new file mode 100644
index 0000000000..09025fc19f
--- /dev/null
+++ b/pkg/noun/v2/hashtable.h
@@ -0,0 +1,42 @@
+#ifndef U3_HASHTABLE_V2_H
+#define U3_HASHTABLE_V2_H
+
+#define u3h_v2_buck          u3h_buck
+#define u3h_v2_free          u3h_free
+#define u3h_v2_new           u3h_new
+#define u3h_v2_node          u3h_node
+#define u3h_v2_noun_to_slot  u3h_noun_to_slot
+#define u3h_v2_root          u3h_root
+#define u3h_v2_slot_is_node  u3h_slot_is_node
+#define u3h_v2_slot_is_noun  u3h_slot_is_noun
+#define u3h_v2_slot_to_noun  u3h_slot_to_noun
+#define u3h_v2_walk          u3h_walk
+#define u3h_v2_walk_with     u3h_walk_with
+
+#include "pkg/noun/hashtable.h"
+
+#include "c3.h"
+#include "types.h"
+
+  /**  Data structures.
+  **/
+
+    /**  HAMT macros.
+    ***
+    ***  Coordinate with u3_noun definition!
+    **/
+      /* u3h_v2_slot_to_node(): slot to node pointer
+      ** u3h_v2_node_to_slot(): node pointer to slot
+      */
+#     define  u3h_v2_slot_to_node(sot)  (u3a_v2_into(((sot) & 0x3fffffff) << u3a_vits))
+#     define  u3h_v2_node_to_slot(ptr)  ((u3a_v2_outa((ptr)) >> u3a_vits) | 0x40000000)
+
+    /**  Functions.
+    ***
+    **/
+      /* u3h_v2_rewrite(): rewrite hashtable for compaction.
+      */
+        void
+        u3h_v2_rewrite(u3p(u3h_root) har_p);
+
+#endif /* U3_HASHTABLE_V2_H */
diff --git a/pkg/noun/v2/jets.c b/pkg/noun/v2/jets.c
new file mode 100644
index 0000000000..c22ea97f3b
--- /dev/null
+++ b/pkg/noun/v2/jets.c
@@ -0,0 +1,54 @@
+/// @file
+
+#include "pkg/noun/vortex.h"
+
+#include "pkg/noun/jets.h"
+#include "pkg/noun/v2/jets.h"
+
+#include "pkg/noun/v2/allocate.h"
+#include "pkg/noun/v2/hashtable.h"
+#include "pkg/noun/v2/vortex.h"
+
+#include "pkg/noun/v3/hashtable.h"
+#include "pkg/noun/v3/jets.h"
+
+/* u3j_v2_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+*/
+void
+u3j_v2_reclaim(void)
+{
+  //  set globals (required for aliased functions)
+  u3H = (u3v_home*) u3H_v2;
+  u3R = (u3a_road*) u3R_v2;
+
+  //  clear the jet hank cache
+  //
+  u3h_v3_walk(u3R->jed.han_p, u3j_v3_free_hank);
+  u3h_v3_free(u3R->jed.han_p);
+  u3R->jed.han_p = u3h_v3_new();
+}
+
+/* u3j_v2_mig_rewrite_compact(): rewrite jet state for compaction.
+ *
+ * NB: u3R_v2->jed.han_p *must* be cleared (currently via u3j_v2_reclaim above)
+ * since it contains hanks which are not nouns but have loom pointers.
+ * Alternately, rewrite the entries with u3h_v2_walk, using u3j_v2_mark as a
+ * template for how to walk.  There's an untested attempt at this in git
+ * history at e8a307a.
+*/
+void
+u3j_v2_mig_rewrite_compact()
+{
+  u3h_v2_rewrite(u3R_v2->jed.war_p);
+  u3h_v2_rewrite(u3R_v2->jed.cod_p);
+  u3h_v2_rewrite(u3R_v2->jed.han_p);
+  u3h_v2_rewrite(u3R_v2->jed.bas_p);
+
+  u3h_v2_rewrite(u3R_v2->jed.hot_p);
+  u3R_v2->jed.hot_p = u3a_v2_rewritten(u3R_v2->jed.hot_p);
+
+  u3R_v2->jed.war_p = u3a_v2_rewritten(u3R_v2->jed.war_p);
+  u3R_v2->jed.cod_p = u3a_v2_rewritten(u3R_v2->jed.cod_p);
+  u3R_v2->jed.han_p = u3a_v2_rewritten(u3R_v2->jed.han_p);
+  u3R_v2->jed.bas_p = u3a_v2_rewritten(u3R_v2->jed.bas_p);
+}
diff --git a/pkg/noun/v2/jets.h b/pkg/noun/v2/jets.h
new file mode 100644
index 0000000000..526046905d
--- /dev/null
+++ b/pkg/noun/v2/jets.h
@@ -0,0 +1,35 @@
+/// @file
+
+#ifndef U3_JETS_V2_H
+#define U3_JETS_V2_H
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/jets.h"
+
+
+  /**  Aliases.
+  **/
+#     define  u3j_v2_core       u3j_core
+#     define  u3j_v2_fink       u3j_fink
+#     define  u3j_v2_fist       u3j_fist
+#     define  u3j_v2_hank       u3j_hank
+#     define  u3j_v2_free_hank  u3j_free_hank
+#     define  u3j_v2_harm       u3j_harm
+#     define  u3j_v2_rite       u3j_rite
+#     define  u3j_v2_site       u3j_site
+#     define  u3j_v2_rite_lose  u3j_rite_lose
+#     define  u3j_v2_site_lose  u3j_site_lose
+
+  /**  Functions.
+  **/
+    /* u3j_v2_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+    */
+      void
+      u3j_v2_reclaim(void);
+
+    /* u3j_v2_mig_rewrite_compact(): rewrite jet state for compaction.
+    */
+      void
+      u3j_v2_mig_rewrite_compact();
+
+#endif /* ifndef U3_JETS_V2_H */
diff --git a/pkg/noun/v2/manage.c b/pkg/noun/v2/manage.c
new file mode 100644
index 0000000000..113ecc2b6b
--- /dev/null
+++ b/pkg/noun/v2/manage.c
@@ -0,0 +1,174 @@
+/// @file
+
+#include "pkg/noun/v2/manage.h"
+
+#include "pkg/noun/v1/allocate.h"
+#include "pkg/noun/v2/allocate.h"
+#include "pkg/noun/v2/hashtable.h"
+#include "pkg/noun/v2/jets.h"
+#include "pkg/noun/v2/nock.h"
+#include "pkg/noun/v2/options.h"
+#include "pkg/noun/vortex.h"
+#include "pkg/noun/v1/vortex.h"
+#include "pkg/noun/v2/vortex.h"
+
+/* _cm_pack_rewrite(): trace through arena, rewriting pointers.
+*/
+static void
+_cm_pack_rewrite(void)
+{
+  u3v_v2_mig_rewrite_compact();
+  u3j_v2_mig_rewrite_compact();
+  u3n_v2_mig_rewrite_compact();
+  u3a_v2_mig_rewrite_compact();
+}
+
+static void
+_migrate_reclaim()
+{
+  //  XX update this and similar printfs
+  fprintf(stderr, "loom: migration reclaim\r\n");
+  u3m_v1_reclaim();
+}
+
+static void
+_migrate_seek(const u3a_v2_road *rod_u)
+{
+  /*
+    very much like u3a_v2_pack_seek with the following changes:
+    - there is no need to account for free space as |pack is performed before
+      the migration
+    - odd sized boxes will be padded by one word to achieve an even size
+    - rut will be moved from one word ahead of u3_Loom to two words ahead
+  */
+  c3_w *    box_w = u3a_v2_into(rod_u->rut_p);
+  c3_w *    end_w = u3a_v2_into(rod_u->hat_p);
+  u3_post   new_p = (rod_u->rut_p + 1 + c3_wiseof(u3a_v2_box));
+  u3a_v2_box * box_u = (void *)box_w;
+
+  fprintf(stderr, "loom: migration seek\r\n");
+
+  for (; box_w < end_w
+         ; box_w += box_u->siz_w
+         , box_u = (void*)box_w)
+    {
+      if (!box_u->use_w)
+        continue;
+      u3_assert(box_u->siz_w);
+      u3_assert(box_u->use_w);
+      box_w[box_u->siz_w - 1] = new_p;
+      new_p = c3_align(new_p + box_u->siz_w, 2, C3_ALGHI);
+    }
+}
+
+static void
+_migrate_rewrite()
+{
+  fprintf(stderr, "loom: migration rewrite\r\n");
+
+  _cm_pack_rewrite();
+}
+
+static void
+_migrate_move(u3a_v2_road *rod_u)
+{
+  fprintf(stderr, "loom: migration move\r\n");
+
+  c3_z hiz_z = u3a_v2_heap(rod_u) * sizeof(c3_w);
+
+  /* calculate required shift distance to prevent write head overlapping read head */
+  c3_w  off_w = 1;  /* at least 1 word because u3R_v1->rut_p migrates from 1 to 2 */
+  for (u3a_v2_box *box_u = u3a_v2_into(rod_u->rut_p)
+         ; (void *)box_u < u3a_v2_into(rod_u->hat_p)
+         ; box_u = (void *)((c3_w *)box_u + box_u->siz_w))
+    off_w += box_u->siz_w & 1; /* odd-sized boxes are padded by one word */
+
+  /* shift */
+  memmove(u3a_v2_into(u3H_v2->rod_u.rut_p + off_w),
+          u3a_v2_into(u3H_v2->rod_u.rut_p),
+          hiz_z);
+  /* manually zero the former rut */
+  *(c3_w *)u3a_v2_into(rod_u->rut_p) = 0;
+
+  /* relocate boxes to DWORD-aligned addresses stored in trailing size word */
+  c3_w *box_w = u3a_v2_into(rod_u->rut_p + off_w);
+  c3_w *end_w = u3a_v2_into(rod_u->hat_p + off_w);
+  u3a_v2_box *old_u = (void *)box_w;
+  c3_w siz_w = old_u->siz_w;
+  u3p(c3_w) new_p = rod_u->rut_p + 1 + c3_wiseof(u3a_v2_box);
+  c3_w *new_w;
+
+  for (; box_w < end_w
+         ; box_w += siz_w
+         , old_u = (void *)box_w
+         , siz_w = old_u->siz_w) {
+    old_u->use_w &= 0x7fffffff;
+
+    if (!old_u->use_w)
+      continue;
+
+    new_w = (void *)u3a_v2_botox(u3a_v2_into(new_p));
+    u3_assert(box_w[siz_w - 1] == new_p);
+    u3_assert(new_w <= box_w);
+
+    c3_w i_w;
+    for (i_w = 0; i_w < siz_w - 1; i_w++)
+      new_w[i_w] = box_w[i_w];
+
+    if (siz_w & 1) {
+      new_w[i_w++] = 0;         /* pad odd sized boxes */
+      new_w[i_w++] = siz_w + 1; /* restore trailing size word */
+      new_w[0] = siz_w + 1;     /* and the leading size word */
+    }
+    else {
+      new_w[i_w++] = siz_w;
+    }
+
+    new_p += i_w;
+  }
+
+  /* restore proper heap state */
+  rod_u->rut_p = 2;
+  rod_u->hat_p = new_p - c3_wiseof(u3a_v2_box);
+
+  /* like |pack, clear the free lists and cell allocator */
+  for (c3_w i_w = 0; i_w < u3a_v2_fbox_no; i_w++)
+    u3R_v1->all.fre_p[i_w] = 0;
+
+  u3R_v1->all.fre_w = 0;
+  u3R_v1->all.cel_p = 0;
+}
+
+
+/* u3m_v2_migrate: perform loom migration if necessary.
+*/
+void
+u3m_v2_migrate()
+{
+  c3_w len_w = u3C_v2.wor_i - 1;
+  c3_w ver_w = *(u3_Loom + len_w);
+
+  u3_assert( U3V_VER1 == ver_w );
+
+  c3_w* mem_w = u3_Loom + 1;
+  c3_w  siz_w = c3_wiseof(u3v_v1_home);
+  c3_w* mat_w = (mem_w + len_w) - siz_w;
+
+  u3H_v1 = (void *)mat_w;
+  u3R_v1 = &u3H_v1->rod_u;
+
+  u3R_v1->cap_p = u3R_v1->mat_p = u3a_v1_outa(u3H_v1);
+
+  fprintf(stderr, "loom: pointer compression migration running...\r\n");
+
+  /* perform the migration in a pattern similar to |pack */
+  _migrate_reclaim();
+  _migrate_seek(&u3H_v1->rod_u);
+  _migrate_rewrite();
+  _migrate_move(&u3H_v1->rod_u);
+
+  /* finally update the version and commit to disk */
+  u3H_v1->ver_w = U3V_VER2;
+
+  fprintf(stderr, "loom: pointer compression migration done\r\n");
+}
diff --git a/pkg/noun/v2/manage.h b/pkg/noun/v2/manage.h
new file mode 100644
index 0000000000..1d03b97809
--- /dev/null
+++ b/pkg/noun/v2/manage.h
@@ -0,0 +1,13 @@
+/// @file
+
+#ifndef U3_MANAGE_V2_H
+#define U3_MANAGE_V2_H
+
+    /**  System management.
+    **/
+      /* u3m_v2_migrate: perform pointer compression loom migration if necessary.
+      */
+        void
+        u3m_v2_migrate();
+
+#endif /* ifndef U3_MANAGE_V2_H */
diff --git a/pkg/noun/v2/nock.c b/pkg/noun/v2/nock.c
new file mode 100644
index 0000000000..e6ff116ce1
--- /dev/null
+++ b/pkg/noun/v2/nock.c
@@ -0,0 +1,92 @@
+/// @file
+
+#include "pkg/noun/v2/nock.h"
+
+#include "pkg/noun/vortex.h"
+
+#include "pkg/noun/v2/allocate.h"
+#include "pkg/noun/v2/hashtable.h"
+#include "pkg/noun/v2/vortex.h"
+
+#include "pkg/noun/v3/hashtable.h"
+
+/* u3n_v2_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+*/
+void
+u3n_v2_reclaim(void)
+{
+  //  set globals (required for aliased functions)
+  u3H = (u3v_home*) u3H_v2;
+  u3R = (u3a_road*) u3R_v2;
+
+  //  clear the bytecode cache
+  u3n_v2_free();
+  u3R->byc.har_p = u3h_v2_new();
+}
+
+/* _cn_v2_prog_free(): free memory retained by program pog_u
+*/
+static void
+_cn_v2_prog_free(u3n_v2_prog* pog_u)
+{
+  // fix up pointers for loom portability
+  pog_u->byc_u.ops_y = (c3_y*) ((void*) pog_u) + sizeof(u3n_v2_prog);
+  pog_u->lit_u.non   = (u3_noun*) (pog_u->byc_u.ops_y + pog_u->byc_u.len_w);
+  pog_u->mem_u.sot_u = (u3n_v2_memo*) (pog_u->lit_u.non + pog_u->lit_u.len_w);
+  pog_u->cal_u.sit_u = (u3j_v2_site*) (pog_u->mem_u.sot_u + pog_u->mem_u.len_w);
+  pog_u->reg_u.rit_u = (u3j_v2_rite*) (pog_u->cal_u.sit_u + pog_u->cal_u.len_w);
+
+  c3_w dex_w;
+  for (dex_w = 0; dex_w < pog_u->lit_u.len_w; ++dex_w) {
+    u3a_v2_lose(pog_u->lit_u.non[dex_w]);
+  }
+  for (dex_w = 0; dex_w < pog_u->mem_u.len_w; ++dex_w) {
+    u3a_v2_lose(pog_u->mem_u.sot_u[dex_w].key);
+  }
+  for (dex_w = 0; dex_w < pog_u->cal_u.len_w; ++dex_w) {
+    u3j_v2_site_lose(&(pog_u->cal_u.sit_u[dex_w]));
+  }
+  for (dex_w = 0; dex_w < pog_u->reg_u.len_w; ++dex_w) {
+    u3j_v2_rite_lose(&(pog_u->reg_u.rit_u[dex_w]));
+  }
+  u3a_v2_free(pog_u);
+}
+
+/* _n_v2_feb(): u3h_v2_walk helper for u3n_v2_free
+ */
+static void
+_n_v2_feb(u3_noun kev)
+{
+  u3a_v2_cell *cel_u = (u3a_v2_cell*) u3a_v2_to_ptr(kev);
+  _cn_v2_prog_free(u3to(u3n_v2_prog, cel_u->tel));
+}
+
+/* u3n_v2_free(): free bytecode cache
+ */
+void
+u3n_v2_free()
+{
+  u3p(u3h_v2_root) har_p = u3R_v2->byc.har_p;
+  u3h_v2_walk(har_p, _n_v2_feb);
+  u3h_v2_free(har_p);
+}
+
+/* u3n_v2_mig_rewrite_compact(): rewrite the bytecode cache for compaction.
+ *
+ * NB: u3R_v2->byc.har_p *must* be cleared (currently via u3n_v2_reclaim above),
+ * since it contains things that look like nouns but aren't.
+ * Specifically, it contains "cells" where the tail is a
+ * pointer to a u3a_v2_malloc'ed block that contains loom pointers.
+ *
+ * You should be able to walk this with u3h_v2_walk and rewrite the
+ * pointers, but you need to be careful to handle that u3a_v2_malloc
+ * pointers can't be turned into a box by stepping back two words. You
+ * must step back one word to get the padding, step then step back that
+ * many more words (plus one?).
+ */
+void
+u3n_v2_mig_rewrite_compact()
+{
+  u3h_v2_rewrite(u3R_v2->byc.har_p);
+  u3R_v2->byc.har_p = u3a_v2_rewritten(u3R_v2->byc.har_p);
+}
diff --git a/pkg/noun/v2/nock.h b/pkg/noun/v2/nock.h
new file mode 100644
index 0000000000..e7d44aee08
--- /dev/null
+++ b/pkg/noun/v2/nock.h
@@ -0,0 +1,64 @@
+/// @file
+
+#ifndef U3_NOCK_V2_H
+#define U3_NOCK_V2_H
+
+#include "pkg/noun/v3/nock.h"
+
+#include "pkg/noun/v2/jets.h"
+
+#include "types.h"
+
+  /** Data structures.
+  **/
+    /* u3n_memo: %memo hint space
+     */
+    typedef struct {
+      c3_l    sip_l;
+      u3_noun key;
+    } u3n_v2_memo;
+
+  /* u3n_v2_prog: program compiled from nock
+   */
+  typedef struct _u3n_v2_prog {
+    struct {
+      c3_o      own_o;                // program owns ops_y?
+      c3_w      len_w;                // length of bytecode (bytes)
+      c3_y*     ops_y;                // actual array of bytes
+    } byc_u;                          // bytecode
+    struct {
+      c3_w      len_w;                // number of literals
+      u3_noun*  non;                  // array of literals
+    } lit_u;                          // literals
+    struct {
+      c3_w      len_w;                // number of memo slots
+      u3n_v2_memo* sot_u;             // array of memo slots
+    } mem_u;                          // memo slot data
+    struct {
+      c3_w      len_w;                // number of calls sites
+      u3j_v2_site* sit_u;             // array of sites
+    } cal_u;                          // call site data
+    struct {
+      c3_w      len_w;                // number of registration sites
+      u3j_v2_rite* rit_u;             // array of sites
+    } reg_u;                          // registration site data
+  } u3n_v2_prog;
+
+  /**  Functions.
+  **/
+    /* u3n_v2_reclaim(): clear ad-hoc persistent caches to reclaim memory.
+    */
+      void
+      u3n_v2_reclaim(void);
+
+    /* u3n_v2_free(): free bytecode cache.
+     */
+      void
+      u3n_v2_free(void);
+
+    /* u3n_v2_mig_rewrite_compact(): rewrite bytecode cache for compaction.
+     */
+      void
+      u3n_v2_mig_rewrite_compact();
+
+#endif /* ifndef U3_NOCK_V2_H */
diff --git a/pkg/noun/v2/options.h b/pkg/noun/v2/options.h
new file mode 100644
index 0000000000..4af573f20d
--- /dev/null
+++ b/pkg/noun/v2/options.h
@@ -0,0 +1,14 @@
+/// @file
+
+#ifndef U3_OPTIONS_V2_H
+#define U3_OPTIONS_V2_H
+
+#include "pkg/noun/options.h"
+
+  /** Globals.
+  **/
+    /* u3_Config / u3C: global memory control.
+    */
+#     define u3C_v2  u3C
+
+#endif /* ifndef U3_OPTIONS_H */
diff --git a/pkg/noun/v2/vortex.c b/pkg/noun/v2/vortex.c
new file mode 100644
index 0000000000..b22dfaed4d
--- /dev/null
+++ b/pkg/noun/v2/vortex.c
@@ -0,0 +1,25 @@
+/// @file
+
+#include "pkg/noun/vortex.h"
+#include "pkg/noun/v2/vortex.h"
+
+#include "pkg/noun/v2/allocate.h"
+
+u3v_v2_home* u3v_v2_Home;
+
+/* u3v_v2_mig_rewrite_compact(): rewrite arvo kernel for compaction.
+*/
+void
+u3v_v2_mig_rewrite_compact()
+{
+  u3v_v2_arvo* arv_u = &(u3H_v2->arv_u);
+
+  u3a_v2_rewrite_noun(arv_u->roc);
+  u3a_v2_rewrite_noun(arv_u->now);
+  u3a_v2_rewrite_noun(arv_u->yot);
+
+  arv_u->roc = u3a_v2_rewritten_noun(arv_u->roc);
+  arv_u->now = u3a_v2_rewritten_noun(arv_u->now);
+  arv_u->yot = u3a_v2_rewritten_noun(arv_u->yot);
+}
+
diff --git a/pkg/noun/v2/vortex.h b/pkg/noun/v2/vortex.h
new file mode 100644
index 0000000000..ee8a2f861e
--- /dev/null
+++ b/pkg/noun/v2/vortex.h
@@ -0,0 +1,40 @@
+/// @file
+
+#ifndef U3_VORTEX_V2_H
+#define U3_VORTEX_V2_H
+
+#include "pkg/noun/vortex.h"
+
+#include "pkg/noun/v2/allocate.h"
+#include "pkg/noun/version.h"
+
+  /**  Aliases.
+  **/
+#     define     u3v_v2_arvo  u3v_arvo
+
+  /**  Data structures.
+  **/
+    /* u3v_v2_home: all internal (within image) state.
+    **       NB: version must be last for discriminability in north road
+    */
+      typedef struct _u3v_v2_home {
+        u3a_v2_road    rod_u;                //  storage state
+        u3v_v2_arvo    arv_u;                //  arvo state
+        u3v_version    ver_w;                //  version number
+      } u3v_v2_home;
+
+  /**  Globals.
+  **/
+      /// Arvo internal state.
+      extern u3v_v2_home* u3v_v2_Home;
+#       define u3H_v2  u3v_v2_Home
+#       define u3A_v2  (&(u3v_v2_Home->arv_u))
+
+  /**  Functions.
+  **/
+    /* u3v_v2_mig_rewrite_compact(): rewrite arvo kernel for compaction.
+    */
+      void
+      u3v_v2_mig_rewrite_compact();
+
+#endif /* ifndef U3_VORTEX_V2_H */
diff --git a/pkg/noun/v3/allocate.h b/pkg/noun/v3/allocate.h
new file mode 100644
index 0000000000..bacc79e174
--- /dev/null
+++ b/pkg/noun/v3/allocate.h
@@ -0,0 +1,17 @@
+#ifndef U3_ALLOCATE_V3_H
+#define U3_ALLOCATE_V3_H
+
+#include "pkg/noun/allocate.h"
+
+#include "pkg/noun/v3/manage.h"
+#include "options.h"
+
+  /**  Aliases.
+  **/
+#     define u3R_v3              u3a_Road
+#     define u3a_v3_balign       u3a_balign
+#     define u3a_v3_road         u3a_road
+#     define u3a_v3_walign       u3a_walign
+#     define u3a_v3_walloc       u3a_walloc
+
+#endif /* ifndef U3_ALLOCATE_V3_H */
diff --git a/pkg/noun/v3/hashtable.c b/pkg/noun/v3/hashtable.c
new file mode 100644
index 0000000000..b17d7b6e78
--- /dev/null
+++ b/pkg/noun/v3/hashtable.c
@@ -0,0 +1,33 @@
+/// @file
+
+#include "pkg/noun/v3/hashtable.h"
+
+#include "pkg/noun/allocate.h"
+#include "pkg/noun/vortex.h"
+
+#include "pkg/noun/v3/allocate.h"
+#include "pkg/noun/v3/vortex.h"
+
+/* u3h_v3_new_cache(): create hashtable with bounded size.
+*/
+u3p(u3h_v3_root)
+u3h_v3_new_cache(c3_w max_w)
+{
+  //  set globals (required for aliased functions)
+  u3H = (u3v_home*) u3H_v3;
+  u3R = (u3a_road*) u3R_v3;
+
+  u3h_v3_root*     har_u = u3a_v3_walloc(c3_wiseof(u3h_v3_root));
+  u3p(u3h_v3_root) har_p = u3of(u3h_v3_root, har_u);
+  c3_w        i_w;
+
+  har_u->max_w       = max_w;
+  har_u->use_w       = 0;
+  har_u->arm_u.mug_w = 0;
+  har_u->arm_u.inx_w = 0;
+
+  for ( i_w = 0; i_w < 64; i_w++ ) {
+    har_u->sot_w[i_w] = 0;
+  }
+  return har_p;
+}
diff --git a/pkg/noun/v3/hashtable.h b/pkg/noun/v3/hashtable.h
new file mode 100644
index 0000000000..14e0e47753
--- /dev/null
+++ b/pkg/noun/v3/hashtable.h
@@ -0,0 +1,18 @@
+#ifndef U3_HASHTABLE_V3_H
+#define U3_HASHTABLE_V3_H
+
+#define u3h_v3_free          u3h_free
+#define u3h_v3_new           u3h_new
+#define u3h_v3_root          u3h_root
+#define u3h_v3_walk          u3h_walk
+
+#include "pkg/noun/hashtable.h"
+
+  /**  Functions.
+  **/
+    /* u3h_v3_new_cache(): create hashtable with bounded size.
+    */
+      u3p(u3h_v3_root)
+      u3h_v3_new_cache(c3_w clk_w);
+
+#endif /* U3_HASHTABLE_V3_H */
diff --git a/pkg/noun/v3/jets.h b/pkg/noun/v3/jets.h
new file mode 100644
index 0000000000..a0fe54f9d7
--- /dev/null
+++ b/pkg/noun/v3/jets.h
@@ -0,0 +1,12 @@
+/// @file
+
+#ifndef U3_JETS_V3_H
+#define U3_JETS_V3_H
+
+#include "pkg/noun/jets.h"
+
+  /**  Aliases.
+  **/
+#     define  u3j_v3_free_hank  u3j_free_hank
+
+#endif /* ifndef U3_JETS_V3_H */
diff --git a/pkg/noun/v3/manage.c b/pkg/noun/v3/manage.c
new file mode 100644
index 0000000000..a15d5ad9be
--- /dev/null
+++ b/pkg/noun/v3/manage.c
@@ -0,0 +1,107 @@
+/// @file
+
+#include "pkg/noun/v3/manage.h"
+
+#include "pkg/noun/v2/jets.h"
+#include "pkg/noun/v2/nock.h"
+#include "pkg/noun/v2/vortex.h"
+
+#include "pkg/noun/v3/allocate.h"
+#include "pkg/noun/v3/hashtable.h"
+#include "pkg/noun/version.h"
+#include "pkg/noun/v3/vortex.h"
+#include <v2/allocate.h>
+
+/* u3m_v3_migrate: perform loom migration if necessary.
+*/
+void
+u3m_v3_migrate()
+{
+  fprintf(stderr, "loom: memoization migration running...\r\n");
+
+
+  c3_w ver_w = *(u3_Loom + u3C.wor_i - 1);
+  c3_w *mem_w = u3_Loom + u3a_v3_walign;
+  c3_w  len_w = u3C.wor_i - u3a_v3_walign;
+  c3_w  suz_w = c3_wiseof(u3v_v2_home);
+  c3_w *mut_w = c3_align(mem_w + len_w - suz_w, u3a_v3_balign, C3_ALGLO);
+
+  //  old road
+  u3v_v2_home* hum_u = (u3v_v2_home*)mut_w;
+  u3a_v2_road* rud_u = &hum_u->rod_u;
+  size_t ruz_t = sizeof(u3a_v2_road);
+
+  //  set v2 globals
+  u3H_v2 = (void *)mut_w;
+  u3R_v2 = &u3H_v2->rod_u;
+  u3R_v2->cap_p = u3R_v2->mat_p = u3a_v2_outa(u3H_v2);
+
+  //  free bytecode caches in old road
+  u3j_v2_reclaim();
+  u3n_v2_reclaim();
+
+  //  new home, new road
+  u3v_v3_home hom_u = {0};
+  u3a_v3_road rod_u = {0};
+
+  //  copy members, one-by-one, from old road to new road
+  rod_u.par_p = rud_u->par_p;
+  rod_u.kid_p = rud_u->kid_p;
+  rod_u.nex_p = rud_u->nex_p;
+
+  rod_u.cap_p = rud_u->cap_p;
+  rod_u.hat_p = rud_u->hat_p;
+  rod_u.mat_p = rud_u->mat_p;
+  rod_u.rut_p = rud_u->rut_p;
+  rod_u.ear_p = rud_u->ear_p;
+
+  //  no need to zero-out fut_w
+  //  no need to do anything with esc
+
+  rod_u.how.fag_w = rud_u->how.fag_w;
+
+  memcpy(rod_u.all.fre_p, rud_u->all.fre_p, sizeof(rud_u->all.fre_p));
+  rod_u.all.cel_p = rud_u->all.cel_p;
+  rod_u.all.fre_w = rud_u->all.fre_w;
+  rod_u.all.max_w = rud_u->all.max_w;
+
+  rod_u.jed.hot_p = rud_u->jed.hot_p;
+  rod_u.jed.war_p = rud_u->jed.war_p;
+  rod_u.jed.cod_p = rud_u->jed.cod_p;
+  rod_u.jed.han_p = rud_u->jed.han_p;
+  rod_u.jed.bas_p = rud_u->jed.bas_p;
+
+  rod_u.byc.har_p = rud_u->byc.har_p;
+
+  rod_u.ski.gul = rud_u->ski.gul;
+
+  rod_u.bug.tax = rud_u->bug.tax;
+  rod_u.bug.mer = rud_u->bug.mer;
+
+  rod_u.pro.nox_d = rud_u->pro.nox_d;
+  rod_u.pro.cel_d = rud_u->pro.cel_d;
+  rod_u.pro.don   = rud_u->pro.don;
+  rod_u.pro.trace = rud_u->pro.trace;
+  rod_u.pro.day   = rud_u->pro.day;
+
+  rod_u.cax.har_p = rud_u->cax.har_p;
+
+  //  prepare the new home, update the version
+  hom_u.arv_u = hum_u->arv_u;
+  hom_u.rod_u = rod_u;
+
+  //  place the new home over the old one
+  c3_w  siz_w = c3_wiseof(u3v_v3_home);
+  c3_w *mat_w = c3_align(mem_w + len_w - siz_w, u3a_v3_balign, C3_ALGLO);
+  memcpy(mat_w, &hom_u, sizeof(u3v_v3_home));
+
+  //  set globals
+  u3H_v3 = (void*)mat_w;
+  u3R_v3 = &u3H_v3->rod_u;
+  u3H_v3->ver_w = U3V_VER3;
+
+  //  initialize persistent cache
+  u3R_v3->cax.per_p = u3h_v3_new_cache(u3C.per_w);
+
+  fprintf(stderr, "loom: memoization migration done\r\n");
+}
diff --git a/pkg/noun/v3/manage.h b/pkg/noun/v3/manage.h
new file mode 100644
index 0000000000..5745a6316b
--- /dev/null
+++ b/pkg/noun/v3/manage.h
@@ -0,0 +1,13 @@
+/// @file
+
+#ifndef U3_MANAGE_V3_H
+#define U3_MANAGE_V3_H
+
+    /** System management.
+    **/
+      /* u3m_v3_migrate: perform memoization loom migration if necessary.
+      */
+        void
+        u3m_v3_migrate();
+
+#endif /* ifndef U3_MANAGE_V3_H */
diff --git a/pkg/noun/v3/nock.h b/pkg/noun/v3/nock.h
new file mode 100644
index 0000000000..a7b208ba99
--- /dev/null
+++ b/pkg/noun/v3/nock.h
@@ -0,0 +1,17 @@
+/// @file
+
+#ifndef U3_NOCK_V3_H
+#define U3_NOCK_V3_H
+
+#include "pkg/noun/nock.h"
+
+#include "types.h"
+
+  /**  Aliases.
+  **/
+#     define  u3n_v3_free     u3n_free
+#     define  u3n_v3_memo     u3n_memo
+#     define  u3n_v3_prog     u3n_prog
+#     define  u3n_v3_reclaim  u3n_reclaim
+
+#endif /* ifndef U3_NOCK_V3_H */
diff --git a/pkg/noun/v3/vortex.h b/pkg/noun/v3/vortex.h
new file mode 100644
index 0000000000..d47ac19654
--- /dev/null
+++ b/pkg/noun/v3/vortex.h
@@ -0,0 +1,19 @@
+/// @file
+
+#ifndef U3_VORTEX_V3_H
+#define U3_VORTEX_V3_H
+
+#include "pkg/noun/vortex.h"
+
+#include "pkg/noun/v3/allocate.h"
+#include "pkg/noun/version.h"
+
+  /**  Aliases.
+  **/
+#     define     u3v_v3_arvo             u3v_arvo
+#     define     u3H_v3                  u3v_Home
+#     define     u3A_v3                  (&(u3H_v3)->arv_u)
+#     define     u3v_v3_home             u3v_home
+#     define     u3v_v3_rewrite_compact  u3v_rewrite_compact
+
+#endif /* ifndef U3_VORTEX_V3_H */
diff --git a/pkg/noun/version.h b/pkg/noun/version.h
index f64d0a398e..5cc6acb86d 100644
--- a/pkg/noun/version.h
+++ b/pkg/noun/version.h
@@ -8,7 +8,8 @@ typedef c3_w       u3v_version;
 
 #define U3V_VER1   1
 #define U3V_VER2   2
-#define U3V_VERLAT U3V_VER2
+#define U3V_VER3   3
+#define U3V_VERLAT U3V_VER3
 
 /* EVENTS
  */
@@ -18,4 +19,10 @@ typedef c3_w       u3e_version;
 #define U3E_VER1   1
 #define U3E_VERLAT U3E_VER1
 
+/* DISK FORMAT
+ */
+
+#define U3D_VER1   1
+#define U3D_VERLAT U3L_VER1
+
 #endif /* ifndef U3_VERSION_H */
diff --git a/pkg/noun/vortex.c b/pkg/noun/vortex.c
index 5981068b87..0bb9af8c29 100644
--- a/pkg/noun/vortex.c
+++ b/pkg/noun/vortex.c
@@ -39,18 +39,12 @@ c3_o
 u3v_boot(u3_noun eve)
 {
   c3_d len_d;
-
   {
     u3_noun len = u3qb_lent(eve);
     u3_assert( c3y == u3r_safe_chub(len, &len_d) );
     u3z(len);
   }
 
-  //  ensure zero-initialized kernel
-  //
-  u3A->roc   = 0;
-  u3A->eve_d = 0;
-
   {
     u3_noun pro = u3m_soft(0, u3v_life, eve);
 
@@ -59,6 +53,7 @@ u3v_boot(u3_noun eve)
       return c3n;
     }
 
+    u3z(u3A->roc);
     u3A->roc   = u3k(u3t(pro));
     u3A->eve_d = len_d;
     u3z(pro);
diff --git a/pkg/noun/vortex.h b/pkg/noun/vortex.h
index cbd0f295ff..2d202e831c 100644
--- a/pkg/noun/vortex.h
+++ b/pkg/noun/vortex.h
@@ -37,9 +37,6 @@
 #       define u3H  u3v_Home
 #       define u3A  (&(u3v_Home->arv_u))
 
-  /** Constants.
-  **/
-
   /**  Functions.
   **/
     /* u3v_life(): execute initial lifecycle, producing Arvo core.
diff --git a/pkg/noun/xtract.c b/pkg/noun/xtract.c
index fc59f463d8..a869eb9547 100644
--- a/pkg/noun/xtract.c
+++ b/pkg/noun/xtract.c
@@ -5,21 +5,8 @@
 #include "manage.h"
 #include "retrieve.h"
 
-/* u3x_good(): test for u3_none.
-*/
 u3_noun
-u3x_good(u3_weak som)
-{
-  return ( u3_none == som ) ? u3m_bail(c3__exit) : som;
-}
-
-/* u3x_at (u3at): fragment.
-*/
-u3_noun
-u3x_at(u3_noun axe, u3_noun som)
-{
-  return u3x_good(u3r_at(axe, som));
-}
+u3x_good(u3_weak som);
 
 /* u3x_mean():
 **
@@ -40,94 +27,3 @@ u3x_mean(u3_noun som, ...)
     u3m_bail(c3__exit);
   }
 }
-
-/* u3x_bite(): xtract/default $bloq and $step from $bite.
-*/
-void
-u3x_bite(u3_noun bite, u3_atom* bloq, u3_atom *step)
-{
-  if ( c3n == u3r_bite(bite, bloq, step) ) {
-    u3m_bail(c3__exit);
-  }
-}
-
-/* u3x_cell():
-**
-**   Divide `a` as a cell `[b c]`.
-*/
-void
-u3x_cell(u3_noun  a,
-         u3_noun* b,
-         u3_noun* c)
-{
-  if ( c3n == u3r_cell(a, b, c) ) {
-    u3m_bail(c3__exit);
-  }
-}
-
-/* u3x_trel():
-**
-**   Divide `a` as a trel `[b c d]`, or bail.
-*/
-void
-u3x_trel(u3_noun  a,
-         u3_noun* b,
-         u3_noun* c,
-         u3_noun* d)
-{
-  if ( c3n == u3r_trel(a, b, c, d) ) {
-    u3m_bail(c3__exit);
-  }
-}
-
-/* u3x_qual():
-**
-**   Divide `a` as a quadruple `[b c d e]`.
-*/
-void
-u3x_qual(u3_noun  a,
-         u3_noun* b,
-         u3_noun* c,
-         u3_noun* d,
-         u3_noun* e)
-{
-  if ( c3n == u3r_qual(a, b, c, d, e) ) {
-    u3m_bail(c3__exit);
-  }
-}
-
-/* u3x_quil():
-**
-**   Divide `a` as a quintuple `[b c d e f]`.
-*/
-void
-u3x_quil(u3_noun  a,
-         u3_noun* b,
-         u3_noun* c,
-         u3_noun* d,
-         u3_noun* e,
-         u3_noun* f)
-{
-  if ( c3n == u3r_quil(a, b, c, d, e, f) ) {
-    u3m_bail(c3__exit);
-  }
-}
-
-/* u3x_hext():
-**
-**   Divide `a` as a hextuple `[b c d e f g]`.
-*/
-void
-u3x_hext(u3_noun  a,
-         u3_noun* b,
-         u3_noun* c,
-         u3_noun* d,
-         u3_noun* e,
-         u3_noun* f,
-         u3_noun* g)
-{
-  if ( c3n == u3r_hext(a, b, c, d, e, f, g) ) {
-    u3m_bail(c3__exit);
-  }
-}
-
diff --git a/pkg/noun/xtract.h b/pkg/noun/xtract.h
index cf39011463..343690a8f2 100644
--- a/pkg/noun/xtract.h
+++ b/pkg/noun/xtract.h
@@ -5,6 +5,8 @@
 
 #include "c3.h"
 #include "types.h"
+#include "allocate.h"
+#include "manage.h"
 
   /**  Constants.
   **/
@@ -40,6 +42,21 @@
   **/
     /* Word axis macros.  For 31-bit axes only.
     */
+
+      /* u3x_at (u3at): fragment.
+      */
+#       define u3x_at(a, b)   u3x_good(u3r_at(a, b))
+#       define u3at(a, b)     u3x_at(a, b)
+
+      /* u3x_bite(): xtract/default $bloq and $step from $bite.
+      */
+#       define u3x_bite(a, b, c)                      \
+          do {                                        \
+            if ( c3n == u3r_bite(a, b, c) ) {         \
+              u3m_bail(c3__exit);                     \
+            }                                         \
+          } while (0)
+
       /* u3x_dep(): number of axis bits.
       */
 #       define u3x_dep(a_w)   (c3_bits_word(a_w) - 1)
@@ -61,25 +78,70 @@
 #       define u3x_peg(a_w, b_w) \
           ( (a_w << u3x_dep(b_w)) | (b_w &~ (1 << u3x_dep(b_w))) )
 
-      /* u3x_atom(): atom or exit.
+      /* u3x_cell(): divide `a` as a cell `[b c]`.
+      */
+#       define u3x_cell(a, b, c)                      \
+          do {                                        \
+            if ( c3n == u3r_cell(a, b, c) ) {         \
+              u3m_bail(c3__exit);                     \
+            }                                         \
+          } while (0)
+
+      /* u3x_trel(): divide `a` as a trel `[b c d]`, or bail.
+      */
+#       define u3x_trel(a, b, c, d)                   \
+          do {                                        \
+            if ( c3n == u3r_trel(a, b, c, d) ) {      \
+              u3m_bail(c3__exit);                     \
+            }                                         \
+          } while (0)
+
+      /* u3x_qual(): divide `a` as a quadruple `[b c d e]`.
       */
-#       define u3x_atom(a)                            \
-          ( (c3y == u3a_is_cell(a)) ? u3m_bail(c3__exit) : a )
+#       define u3x_qual(a, b, c, d, e)                \
+          do {                                        \
+            if ( c3n == u3r_qual(a, b, c, d, e) ) {   \
+              u3m_bail(c3__exit);                     \
+            }                                         \
+          } while (0)
+
+      /* u3x_quil(): divide `a` as a quintuple `[b c d e f]`.
+      */
+#       define u3x_quil(a, b, c, d, e, f)                  \
+          do {                                             \
+            if ( c3n == u3r_quil(a, b, c, d, e, f) ) {     \
+              u3m_bail(c3__exit);                          \
+            }                                              \
+          } while (0)
+
+      /* u3x_hext(): divide `a` as a hextuple `[b c d e f g]`.
+      */
+#       define u3x_hext(a, b, c, d, e, f, g)               \
+          do {                                             \
+            if ( c3n == u3r_hext(a, b, c, d, e, f, g) ) {  \
+              u3m_bail(c3__exit);                          \
+            }                                              \
+          } while (0)
 
   /**  Functions.
   **/
     /** u3x_*: read, but bail with c3__exit on a crash.
     **/
-      /* u3x_good(): test for u3_none.
+      /* u3x_atom(): atom or exit.
       */
-        u3_noun
-        u3x_good(u3_weak som);
+        inline u3_atom
+        u3x_atom(u3_noun a)
+        {
+          return ( c3y == u3a_is_cell(a) ) ? u3m_bail(c3__exit) : a;
+        }
 
-      /* u3x_at (u3at): fragment.
+      /* u3x_good(): test for u3_none.
       */
-        u3_noun
-        u3x_at(u3_noun axe, u3_noun som);
-#       define u3at(axe, som) u3x_at(axe, som)
+        inline u3_noun
+        u3x_good(u3_weak som)
+        {
+          return ( u3_none == som ) ? u3m_bail(c3__exit) : som;
+        }
 
       /* u3x_mean():
       **
@@ -89,64 +151,4 @@
         void
         u3x_mean(u3_noun a, ...);
 
-      /* u3x_bite(): xtract/default $bloq and $step from $bite.
-      */
-        void
-        u3x_bite(u3_noun bite, u3_atom* bloq, u3_atom *step);
-
-      /* u3x_cell():
-      **
-      **   Divide `a` as a cell `[b c]`.
-      */
-        void
-        u3x_cell(u3_noun  a,
-                   u3_noun* b,
-                   u3_noun* c);
-
-      /* u3x_trel():
-      **
-      **   Divide `a` as a trel `[b c d]`, or bail.
-      */
-        void
-        u3x_trel(u3_noun  a,
-                   u3_noun* b,
-                   u3_noun* c,
-                   u3_noun* d);
-
-      /* u3x_qual():
-      **
-      **   Divide `a` as a quadruple `[b c d e]`.
-      */
-        void
-        u3x_qual(u3_noun  a,
-                   u3_noun* b,
-                   u3_noun* c,
-                   u3_noun* d,
-                   u3_noun* e);
-
-      /* u3x_quil():
-      **
-      **   Divide `a` as a quintuple `[b c d e f]`.
-      */
-        void
-        u3x_quil(u3_noun  a,
-                   u3_noun* b,
-                   u3_noun* c,
-                   u3_noun* d,
-                   u3_noun* e,
-                   u3_noun* f);
-
-      /* u3x_hext():
-      **
-      **   Divide `a` as a hextuple `[b c d e f g]`.
-      */
-        void
-        u3x_hext(u3_noun  a,
-                   u3_noun* b,
-                   u3_noun* c,
-                   u3_noun* d,
-                   u3_noun* e,
-                   u3_noun* f,
-                   u3_noun* g);
-
 #endif /* ifndef U3_XTRACT_H */
diff --git a/pkg/noun/zave.c b/pkg/noun/zave.c
index 0955af906c..2958bad662 100644
--- a/pkg/noun/zave.c
+++ b/pkg/noun/zave.c
@@ -5,6 +5,7 @@
 #include "allocate.h"
 #include "hashtable.h"
 #include "imprison.h"
+#include "vortex.h"
 
 /* u3z_key(): construct a memo cache-key.  Arguments retained.
 */
@@ -34,30 +35,60 @@ u3z_key_5(c3_m fun, u3_noun one, u3_noun two, u3_noun tri, u3_noun qua, u3_noun
   return u3nc(fun, u3nq(u3k(one), u3k(two), u3k(tri), u3nc(u3k(qua), u3k(qin))));
 }
 
+/* _har(): get the memo cache for the given cid.
+*/
+static u3p(u3h_root)
+_har(u3a_road* rod_u, u3z_cid cid)
+{
+  switch ( cid ) {
+    case u3z_memo_toss:
+      return rod_u->cax.har_p;
+    case u3z_memo_keep:
+      return rod_u->cax.per_p;
+  }
+  u3_assert(0);
+}
+
 /* u3z_find(): find in memo cache.  Arguments retained.
 */
 u3_weak
-u3z_find(u3_noun key)
+u3z_find(u3z_cid cid, u3_noun key)
 {
-  return u3h_get(u3R->cax.har_p, key);
+  if ( u3z_memo_toss == cid ) {
+    return u3h_get(_har(u3R, cid), key);
+  }
+  else {
+    //  XX needs to be benchmarked (up vs. down search)
+    u3a_road* rod_u = &(u3H->rod_u);
+    while ( 1 ) {
+      u3_weak got = u3h_get(_har(rod_u, cid), key);
+      if ( u3_none != got ) {
+        return got;
+      }
+      if ( 0 == rod_u->kid_p ) {
+        return u3_none;
+      }
+      rod_u = u3to(u3a_road, rod_u->kid_p);
+    };
+  }
 }
 u3_weak
-u3z_find_m(c3_m fun, u3_noun one)
+u3z_find_m(u3z_cid cid, c3_m fun, u3_noun one)
 {
   u3_noun key = u3nc(fun, u3k(one));
   u3_weak val;
-
-  val = u3h_get(u3R->cax.har_p, key);
+  val = u3z_find(cid, key);
   u3z(key);
+
   return val;
 }
 
 /* u3z_save(): save in memo cache. TRANSFER key; RETAIN val
 */
 u3_noun
-u3z_save(u3_noun key, u3_noun val)
+u3z_save(u3z_cid cid, u3_noun key, u3_noun val)
 {
-  u3h_put(u3R->cax.har_p, key, u3k(val));
+  u3h_put(_har(u3R, cid), key, u3k(val));
   u3z(key);
   return val;
 }
@@ -65,28 +96,38 @@ u3z_save(u3_noun key, u3_noun val)
 /* u3z_save_m(): save in memo cache. Arguments retained.
 */
 u3_noun
-u3z_save_m(c3_m fun, u3_noun one, u3_noun val)
+u3z_save_m(u3z_cid cid, c3_m fun, u3_noun one, u3_noun val)
 {
   u3_noun key = u3nc(fun, u3k(one));
 
-  u3h_put(u3R->cax.har_p, key, u3k(val));
+  u3h_put(_har(u3R, cid), key, u3k(val));
   u3z(key);
   return val;
 }
 
-/* u3z_uniq(): uniquify with memo cache.
+/* u3z_uniq(): uniquify with memo cache. XX not used.
 */
 u3_noun
-u3z_uniq(u3_noun som)
+u3z_uniq(u3z_cid cid, u3_noun som)
 {
   u3_noun key = u3nc(c3__uniq, u3k(som));
-  u3_noun val = u3h_get(u3R->cax.har_p, key);
+  u3_noun val = u3h_get(_har(u3R, cid), key);
 
   if ( u3_none != val ) {
     u3z(key); u3z(som); return val;
   }
   else {
-    u3h_put(u3R->cax.har_p, key, u3k(som));
+    u3h_put(_har(u3R, cid), key, u3k(som));
     return som;
   }
 }
+
+/* u3z_reap(): promote memoization cache state.
+*/
+void
+u3z_reap(u3z_cid cid, u3p(u3h_root) har_p)
+{
+  u3_assert(u3z_memo_toss != cid);
+
+  u3h_take_uni(_har(u3R, cid), har_p);
+}
diff --git a/pkg/noun/zave.h b/pkg/noun/zave.h
index 44f272da7c..feff83f664 100644
--- a/pkg/noun/zave.h
+++ b/pkg/noun/zave.h
@@ -12,10 +12,18 @@
   ***  and a noun argument to that (logical) function.  Functions
   ***  are predefined by C-level callers, but 0 means nock.
   ***
-  ***  The memo cache is within its road and dies when it falls.
-  ***
   ***  Memo functions RETAIN keys and transfer values.
   **/
+    /* u3z_cid: cache id
+    */
+      typedef enum {
+        u3z_memo_toss  = 0,
+        u3z_memo_keep  = 1,
+        // u3z_memo_ford  = 2,
+        // u3z_memo_ames  = 3,
+        // ...
+      } u3z_cid;
+
     /* u3z_key*(): construct a memo cache-key.  Arguments retained.
     */
       u3_noun u3z_key(c3_m, u3_noun);
@@ -26,20 +34,35 @@
 
     /* u3z_find*(): find in memo cache. Arguments retained
     */
-      u3_weak u3z_find(u3_noun key);
-      u3_weak u3z_find_m(c3_m fun_m, u3_noun one);
+      u3_weak u3z_find(u3z_cid cid, u3_noun key);
+      u3_weak u3z_find_m(u3z_cid cid, c3_m fun_m, u3_noun one);
 
     /* u3z_save(): save in memo cache. TRANSFER key; RETAIN val;
     */
-      u3_noun u3z_save(u3_noun key, u3_noun val);
+      u3_noun u3z_save(u3z_cid cid, u3_noun key, u3_noun val);
 
     /* u3z_save_m(): save in memo cache. Arguments retained
     */
-      u3_noun u3z_save_m(c3_m fun_m, u3_noun one, u3_noun val);
+      u3_noun u3z_save_m(u3z_cid cid, c3_m fun_m, u3_noun one, u3_noun val);
 
     /* u3z_uniq(): uniquify with memo cache.
     */
       u3_noun
-      u3z_uniq(u3_noun som);
+      u3z_uniq(u3z_cid cid, u3_noun som);
+
+    /* u3z_reap(): promote memoization cache state.
+    */
+      void
+      u3z_reap(u3z_cid cid, u3p(u3h_root) har_p);
+
+    /* u3z_free(): free memoization cache.
+    */
+      void
+      u3z_free(u3z_cid cid);
+
+    /* u3z_ream(): refresh after restoring from checkpoint.
+    */
+      void
+      u3z_ream(u3z_cid cid);
 
 #endif /* ifndef U3_ZAVE_H */
diff --git a/pkg/vere/BUILD.bazel b/pkg/vere/BUILD.bazel
index 76f8b47eca..f856ce0047 100644
--- a/pkg/vere/BUILD.bazel
+++ b/pkg/vere/BUILD.bazel
@@ -301,7 +301,7 @@ genrule(
 
     if check && sleep 10 && check; then
       echo "boot success"
-      lensa hood "+hood/exit"
+      lensa hood '+hood/exit'
       while [ -f ./pier/.vere.lock ]; do
         echo "waiting for pier to shut down"
         sleep 5
diff --git a/pkg/vere/db/lmdb.c b/pkg/vere/db/lmdb.c
index 8f8864b77f..f7554019a4 100644
--- a/pkg/vere/db/lmdb.c
+++ b/pkg/vere/db/lmdb.c
@@ -414,7 +414,7 @@ void
 u3_lmdb_read_meta(MDB_env*    env_u,
                   void*       ptr_v,
                   const c3_c* key_c,
-                  void (*read_f)(void*, size_t, void*))
+                  void (*read_f)(void*, ssize_t, void*))
 {
   MDB_txn* txn_u;
   MDB_dbi  mdb_u;
@@ -424,7 +424,7 @@ u3_lmdb_read_meta(MDB_env*    env_u,
   //
   if ( (ret_w = mdb_txn_begin(env_u, 0, MDB_RDONLY, &txn_u)) ) {
     mdb_logerror(stderr, ret_w, "lmdb: meta read: txn_begin fail");
-    return read_f(ptr_v, 0, 0);
+    return read_f(ptr_v, -1, 0);
   }
 
   //  open the database in the transaction
@@ -432,7 +432,7 @@ u3_lmdb_read_meta(MDB_env*    env_u,
   if ( (ret_w =  mdb_dbi_open(txn_u, "META", 0, &mdb_u)) ) {
     mdb_logerror(stderr, ret_w, "lmdb: meta read: dbi_open fail");
     mdb_txn_abort(txn_u);
-    return read_f(ptr_v, 0, 0);
+    return read_f(ptr_v, -1, 0);
   }
 
   //  read by string key, invoking callback with result
@@ -443,7 +443,7 @@ u3_lmdb_read_meta(MDB_env*    env_u,
     if ( (ret_w = mdb_get(txn_u, mdb_u, &key_u, &val_u)) ) {
       mdb_logerror(stderr, ret_w, "lmdb: read failed");
       mdb_txn_abort(txn_u);
-      return read_f(ptr_v, 0, 0);
+      return read_f(ptr_v, -1, 0);
     }
     else {
       read_f(ptr_v, val_u.mv_size, val_u.mv_data);
diff --git a/pkg/vere/db/lmdb.h b/pkg/vere/db/lmdb.h
index aab4e6c9f7..43c6b433ff 100644
--- a/pkg/vere/db/lmdb.h
+++ b/pkg/vere/db/lmdb.h
@@ -63,7 +63,7 @@
       u3_lmdb_read_meta(MDB_env*    env_u,
                         void*       ptr_v,
                         const c3_c* key_c,
-                        void     (*read_f)(void*, size_t, void*));
+                        void     (*read_f)(void*, ssize_t, void*));
 
     /* u3_lmdb_save_meta(): save by string into the META db.
     */
diff --git a/pkg/vere/disk.c b/pkg/vere/disk.c
index 2cc270a368..de141988bd 100644
--- a/pkg/vere/disk.c
+++ b/pkg/vere/disk.c
@@ -1,8 +1,11 @@
 /// @file
 
 #include "noun.h"
+#include "events.h"
 #include "vere.h"
+#include "version.h"
 #include "db/lmdb.h"
+#include <types.h>
 
 struct _cd_read {
   uv_timer_t       tim_u;
@@ -28,6 +31,15 @@ struct _u3_disk_walk {
   c3_o          liv_o;
 };
 
+// for u3_lmdb_init() calls
+static const size_t siz_i =
+#if (defined(U3_CPU_aarch64) && defined(U3_OS_linux))
+  // 500 GiB is as large as musl on aarch64 wants to allow
+  0x7d00000000;
+#else
+  0x10000000000;
+#endif
+
 #undef VERBOSE_DISK
 #undef DISK_TRACE_JAM
 #undef DISK_TRACE_CUE
@@ -650,26 +662,26 @@ u3_disk_save_meta(MDB_env* mdb_u,
   return c3y;
 }
 
+typedef struct {
+  ssize_t hav_i;
+  c3_y    buf_y[16];
+} _mdb_val;
+
+
 /* _disk_meta_read_cb(): copy [val_p] to atom [ptr_v] if present.
 */
 static void
-_disk_meta_read_cb(void* ptr_v, size_t val_i, void* val_p)
+_disk_meta_read_cb(void* ptr_v, ssize_t val_i, void* val_v)
 {
-  u3_weak* mat = ptr_v;
+  _mdb_val* val_u = ptr_v;
+  c3_y*     dat_y = (c3_y*)val_v;
 
-  if ( val_p ) {
-    *mat = u3i_bytes(val_i, val_p);
-  }
-}
+  memset(val_u->buf_y, 0, sizeof(val_u->buf_y));
+  val_u->hav_i = val_i;
 
-/* _disk_read_meta(): read metadata at [key_c], deserialize.
-*/
-static u3_weak
-_disk_read_meta(MDB_env* mdb_u, const c3_c* key_c)
-{
-  u3_weak dat = u3_none;
-  u3_lmdb_read_meta(mdb_u, &dat, key_c, _disk_meta_read_cb);
-  return dat;
+  if ( 0 < val_i ) {
+    memcpy(val_u->buf_y, dat_y, c3_min(val_i, sizeof(val_u->buf_y)));
+  }
 }
 
 /* u3_disk_read_meta(): read metadata.
@@ -680,60 +692,104 @@ u3_disk_read_meta(MDB_env* mdb_u,
                   c3_o*    fak_o,
                   c3_w*    lif_w)
 {
-  u3_weak ver, who, fak, lif;
+  _mdb_val val_u;
 
-  if ( u3_none == (ver = _disk_read_meta(mdb_u, "version")) ) {
+  //  version
+  //
+  u3_lmdb_read_meta(mdb_u, &val_u, "version", _disk_meta_read_cb);
+
+  if ( 0 > val_u.hav_i ) {
     fprintf(stderr, "disk: read meta: no version\r\n");
     return c3n;
   }
-  if ( u3_none == (who = _disk_read_meta(mdb_u, "who")) ) {
-    fprintf(stderr, "disk: read meta: no indentity\r\n");
+  else if ( (1 != val_u.hav_i) || (1 != *val_u.buf_y) ) {
+    fprintf(stderr, "disk: read meta: unknown version %u\r\n", *val_u.buf_y);
     return c3n;
   }
-  if ( u3_none == (fak = _disk_read_meta(mdb_u, "fake")) ) {
-    fprintf(stderr, "disk: read meta: no fake bit\r\n");
+
+  //  identity
+  //
+  u3_lmdb_read_meta(mdb_u, &val_u, "who", _disk_meta_read_cb);
+
+  if ( 0 > val_u.hav_i ) {
+    fprintf(stderr, "disk: read meta: no identity\r\n");
     return c3n;
   }
-  if ( u3_none == (lif = _disk_read_meta(mdb_u, "life")) ) {
-    fprintf(stderr, "disk: read meta: no lifecycle length\r\n");
-    return c3n;
+  else if ( 16 < val_u.hav_i ) {
+    //  NB: non-fatal
+    //
+    fprintf(stderr, "disk: read meta: strange identity\r\n");
   }
 
-  {
-    c3_o val_o = c3y;
+  if ( who_d ) {
+    c3_y* byt_y = val_u.buf_y;
+
+    who_d[0] = (c3_d)byt_y[0]
+             | (c3_d)byt_y[1] << 8
+             | (c3_d)byt_y[2] << 16
+             | (c3_d)byt_y[3] << 24
+             | (c3_d)byt_y[4] << 32
+             | (c3_d)byt_y[5] << 40
+             | (c3_d)byt_y[6] << 48
+             | (c3_d)byt_y[7] << 56;
+
+    byt_y += 8;
+    who_d[1] = (c3_d)byt_y[0]
+             | (c3_d)byt_y[1] << 8
+             | (c3_d)byt_y[2] << 16
+             | (c3_d)byt_y[3] << 24
+             | (c3_d)byt_y[4] << 32
+             | (c3_d)byt_y[5] << 40
+             | (c3_d)byt_y[6] << 48
+             | (c3_d)byt_y[7] << 56;
+  }
 
-    if ( 1 != ver ) {
-      fprintf(stderr, "disk: read meta: unknown version %u\r\n", ver);
-      val_o = c3n;
-    }
-    else if ( !((c3y == fak ) || (c3n == fak )) ) {
-      fprintf(stderr, "disk: read meta: invalid fake bit\r\n");
-      val_o = c3n;
-    }
-    else if ( c3n == u3a_is_cat(lif) ) {
-      fprintf(stderr, "disk: read meta: invalid lifecycle length\r\n");
-      val_o = c3n;
-    }
+  //  fake bit
+  //
+  u3_lmdb_read_meta(mdb_u, &val_u, "fake", _disk_meta_read_cb);
 
-    if ( c3n == val_o ) {
-      u3z(ver); u3z(who); u3z(fak); u3z(lif);
-      return c3n;
+  if ( 0 > val_u.hav_i ) {
+    fprintf(stderr, "disk: read meta: no fake bit\r\n");
+    return c3n;
+  }
+  else if ( 0 == val_u.hav_i ) {
+    if ( fak_o ) {
+      *fak_o = 0;
     }
   }
-
-  if ( who_d ) {
-    u3r_chubs(0, 2, who_d, who);
+  else if ( (1 == val_u.hav_i) || !((*val_u.buf_y) >> 1) ) {
+    if ( fak_o ) {
+      *fak_o = (*val_u.buf_y) & 1;
+    }
+  }
+  else {
+    fprintf(stderr, "disk: read meta: invalid fake bit %u %zd\r\n",
+                    *val_u.buf_y, val_u.hav_i);
+    return c3n;
   }
 
-  if ( fak_o ) {
-    *fak_o = fak;
+  //  life
+  //
+  u3_lmdb_read_meta(mdb_u, &val_u, "life", _disk_meta_read_cb);
+
+  if ( 0 > val_u.hav_i ) {
+    fprintf(stderr, "disk: read meta: no lifecycle length\r\n");
+    return c3n;
+  }
+  else if ( 4 < val_u.hav_i ) {
+    //  NB: non-fatal
+    //
+    fprintf(stderr, "disk: read meta: strange life\r\n");
   }
 
   if ( lif_w ) {
-    *lif_w = lif;
+    c3_y* byt_y = val_u.buf_y;
+    *lif_w = (c3_w)byt_y[0]
+           | (c3_w)byt_y[1] << 8
+           | (c3_w)byt_y[2] << 16
+           | (c3_w)byt_y[3] << 24;
   }
 
-  u3z(who);
   return c3y;
 }
 
@@ -960,6 +1016,537 @@ u3_disk_slog(u3_disk* log_u)
   }
 }
 
+/* _disk_epoc_meta: read metadata from epoch.
+*/
+static c3_o
+_disk_epoc_meta(u3_disk*    log_u,
+                c3_d        epo_d,
+                const c3_c* met_c,
+                c3_w        max_w,
+                c3_c*       buf_c)
+{
+  struct stat buf_u;
+  c3_w red_w, len_w;
+  c3_i ret_i, fid_i;
+  c3_c*       pat_c;
+
+  ret_i = asprintf(&pat_c, "%s/0i%" PRIc3_d "/%s.txt",
+                   log_u->com_u->pax_c, epo_d, met_c);
+  u3_assert( ret_i > 0 );
+
+  fid_i = c3_open(pat_c, O_RDONLY, 0644);
+  c3_free(pat_c);
+
+  if ( (fid_i < 0) || (fstat(fid_i, &buf_u) < 0) ) {
+    fprintf(stderr, "disk: failed to open %s.txt in epoch 0i%" PRIc3_d "\r\n",
+                    met_c, epo_d);
+    return c3n;
+  }
+  else if ( buf_u.st_size >= max_w ) {
+    fprintf(stderr, "disk: %s.txt in epoch 0i%" PRIc3_d " too large "
+                    "(%" PRIc3_z ")\r\n",
+                    met_c, epo_d, (c3_z)buf_u.st_size);
+    return c3n;
+  }
+
+  len_w = buf_u.st_size;
+  red_w = read(fid_i, buf_c, len_w);
+  close(fid_i);
+
+  if ( len_w != red_w ) {
+    fprintf(stderr, "disk: failed to read %s.txt in epoch 0i%" PRIc3_d "\r\n",
+                    met_c, epo_d);
+    return c3n;
+  }
+
+  //  trim trailing whitespace
+  //
+  do {
+    buf_c[len_w] = 0;
+  }
+  while ( len_w-- && isspace(buf_c[len_w]) );
+
+  return c3y;
+}
+
+/* u3_disk_epoc_init: create new epoch.
+*/
+c3_o
+u3_disk_epoc_init(u3_disk* log_u, c3_d epo_d)
+{
+  //  check if any epoch directories exist
+  c3_d lat_d;
+  c3_o eps_o = u3_disk_epoc_last(log_u, &lat_d);
+
+  //  create new epoch directory if it doesn't exist
+  c3_c epo_c[8193];
+  c3_i epo_i;
+  snprintf(epo_c, sizeof(epo_c), "%s/0i%" PRIc3_d, log_u->com_u->pax_c, epo_d);
+  c3_d ret_d = c3_mkdir(epo_c, 0700);
+  if ( ( ret_d < 0 ) && ( errno != EEXIST ) ) {
+    fprintf(stderr, "disk: create epoch dir %" PRIc3_d " failed: %s\r\n",
+                    epo_d, strerror(errno));
+    return c3n;
+  }
+
+  //  copy snapshot files (skip if first epoch)
+  if ( epo_d > 0 ) {
+    c3_c chk_c[8193];
+    snprintf(chk_c, 8192, "%s/.urb/chk", u3_Host.dir_c);
+    if ( c3n == u3e_backup(chk_c, epo_c, c3y) ) {
+      fprintf(stderr, "disk: copy epoch snapshot failed\r\n");
+      goto fail1;
+    }
+  }
+
+  if ( -1 == (epo_i = c3_open(epo_c, O_RDONLY)) ) {
+    fprintf(stderr, "disk: open epoch dir %" PRIc3_d " failed: %s\r\n",
+                    epo_d, strerror(errno));
+    goto fail1;
+  }
+
+  if ( -1 == c3_sync(epo_i) ) {  //  XX fdatasync on linux?
+    fprintf(stderr, "disk: sync epoch dir %" PRIc3_d " failed: %s\r\n",
+                    epo_d, strerror(errno));
+    goto fail2;
+  }
+
+  //  create epoch version file, overwriting any existing file
+  c3_c epv_c[8193];
+  snprintf(epv_c, sizeof(epv_c), "%s/epoc.txt", epo_c);
+  FILE* epv_f = fopen(epv_c, "w");  // XX errors
+  fprintf(epv_f, "%d", U3D_VER1);
+  fclose(epv_f);
+
+  //  create binary version file, overwriting any existing file
+  c3_c biv_c[8193];
+  snprintf(biv_c, sizeof(biv_c), "%s/vere.txt", epo_c);
+  FILE* biv_f = fopen(biv_c, "w");  //  XX errors
+  fprintf(biv_f, URBIT_VERSION);
+  fclose(biv_f);
+
+  //  get metadata from old epoch or unmigrated event log's db
+  c3_d     who_d[2];
+  c3_o     fak_o;
+  c3_w     lif_w;
+  if ( c3y == eps_o ) {  //  skip if no epochs yet
+    if ( c3y != u3_disk_read_meta(log_u->mdb_u, who_d, &fak_o, &lif_w) ) {
+      fprintf(stderr, "disk: failed to read metadata\r\n");
+      goto fail3;
+    }
+
+    u3_lmdb_exit(log_u->mdb_u);
+    log_u->mdb_u = 0;
+  }
+
+  //  initialize db of new epoch
+  if ( c3y == u3_Host.ops_u.nuu || epo_d > 0 ) {
+    c3_c dat_c[8193];
+    snprintf(dat_c, sizeof(dat_c), "%s/data.mdb", epo_c);
+
+    if ( 0 == (log_u->mdb_u = u3_lmdb_init(epo_c, siz_i)) ) {
+      fprintf(stderr, "disk: failed to initialize database\r\n");
+      c3_free(log_u);
+      goto fail3;
+    }
+  }
+
+  // write the metadata to the database
+  if ( c3y == eps_o ) {
+    if ( c3n == u3_disk_save_meta(log_u->mdb_u, who_d, fak_o, lif_w) ) {
+      fprintf(stderr, "disk: failed to save metadata\r\n");
+      goto fail3;
+    }
+  }
+
+  if ( -1 == c3_sync(epo_i) ) {  //  XX fdatasync on linux?
+    fprintf(stderr, "disk: sync epoch dir %" PRIc3_d " failed: %s\r\n",
+                    epo_d, strerror(errno));
+    goto fail3;
+  }
+
+  close(epo_i);
+
+  //  load new epoch directory and set it in log_u
+  log_u->epo_d = epo_d;
+
+  //  success
+  return c3y;
+
+fail3:
+  c3_unlink(epv_c);
+  c3_unlink(biv_c);
+fail2:
+  close(epo_i);
+fail1:
+  c3_rmdir(epo_c);
+  return c3n;
+}
+
+/* u3_disk_epoc_kill: delete an epoch.
+*/
+c3_o
+u3_disk_epoc_kill(u3_disk* log_u, c3_d epo_d)
+{
+  //  get epoch directory
+  c3_c epo_c[8193];
+  snprintf(epo_c, sizeof(epo_c), "%s/0i%" PRIc3_d, log_u->com_u->pax_c, epo_d);
+
+  //  delete files in epoch directory
+  u3_dire* dir_u = u3_foil_folder(epo_c);
+  u3_dent* den_u = dir_u->all_u;
+  while ( den_u ) {
+    c3_c fil_c[8193];
+    snprintf(fil_c, sizeof(fil_c), "%s/%s", epo_c, den_u->nam_c);
+    if ( 0 != c3_unlink(fil_c) ) {
+      fprintf(stderr, "disk: failed to delete file in epoch directory\r\n");
+      return c3n;
+    }
+    den_u = den_u->nex_u;
+  }
+
+  //  delete epoch directory
+  if ( 0 != c3_rmdir(epo_c) ) {
+    fprintf(stderr, "disk: failed to delete epoch directory\r\n");
+    return c3n;
+  }
+
+  //  cleanup
+  u3_dire_free(dir_u);
+
+  //  success
+  return c3y;
+}
+
+/* u3_disk_epoc_last: get latest epoch number.
+*/
+c3_o
+u3_disk_epoc_last(u3_disk* log_u, c3_d* lat_d)
+{
+  u3_dire* die_u = u3_foil_folder(log_u->com_u->pax_c);
+  u3_dent* den_u = die_u->dil_u;
+  c3_o     ret_o = c3n;
+
+  *lat_d = 0;
+
+  while ( den_u ) {
+    c3_d epo_d = 0;
+    if ( 1 == sscanf(den_u->nam_c, "0i%" PRIc3_d, &epo_d) ) {
+      ret_o = c3y;   //  NB: returns yes if the directory merely exists
+      *lat_d = c3_max(epo_d, *lat_d);  //  update the latest epoch number
+    }
+    den_u = den_u->nex_u;
+  }
+
+  u3_dire_free(die_u);
+
+  return ret_o;
+}
+
+/* u3_disk_epoc_list: get descending epoch numbers, "mcut" pattern.
+*/
+c3_z
+u3_disk_epoc_list(u3_disk* log_u, c3_d* sot_d)
+{
+  u3_dire* ned_u = u3_foil_folder(log_u->com_u->pax_c);
+  u3_dent* den_u = ned_u->dil_u;
+  c3_z     len_z = 0;
+
+  while ( den_u ) {  //  count epochs
+    len_z++;
+    den_u = den_u->nex_u;
+  }
+
+  if ( !sot_d ) {
+    u3_dire_free(ned_u);
+    return len_z;
+  }
+
+  len_z = 0;
+  den_u = ned_u->dil_u;
+
+  while ( den_u ) {
+    if ( 1 == sscanf(den_u->nam_c, "0i%" PRIc3_d, (sot_d + len_z)) ) {
+      len_z++;
+    }
+    den_u = den_u->nex_u;
+  }
+
+  //  sort sot_d naively in descending order
+  //
+  c3_d tmp_d;
+  for ( c3_z i_z = 0; i_z < len_z; i_z++ ) {
+    for ( c3_z j_z = i_z + 1; j_z < len_z; j_z++ ) {
+      if ( sot_d[i_z] < sot_d[j_z] ) {
+        tmp_d = sot_d[i_z];
+        sot_d[i_z] = sot_d[j_z];
+        sot_d[j_z] = tmp_d;
+      }
+    }
+  }
+
+  u3_dire_free(ned_u);
+  return len_z;
+}
+
+/* _disk_need_migrate: does the disk need to be migrated?
+*/
+static c3_o
+_disk_need_migrate(u3_disk* log_u)
+{
+  c3_c dut_c[8193];
+  snprintf(dut_c, sizeof(dut_c), "%s/data.mdb", log_u->com_u->pax_c);
+
+  //  check if data.mdb is readable in log directory
+  //
+  if ( 0 == access(dut_c, F_OK)) {
+    return c3y;
+  }
+
+  return c3n;
+}
+
+/* _disk_migrate: migrates disk format.
+ */
+static c3_o
+_disk_migrate(u3_disk* log_u, c3_d eve_d)
+{
+  /*  migration steps:
+   *  0. detect whether we need to migrate or not
+   *     a. if it's a fresh boot via u3_Host.ops_u.nuu -> skip migration
+   *     b. if data.mdb is readable in log directory -> execute migration
+   *        if not -> skip migration (returns yes)
+   *  1. initialize epoch 0i0 (first call to u3_disk_epoc_init())
+   *     a. creates epoch directory
+   *     b. creates epoch version file
+   *     c. creates binary version file
+   *     d. initializes database
+   *     e. reads metadata from old database
+   *     f. writes metadata to new database
+   *     g. loads new epoch directory and sets it in log_u
+   *  2. create hard links to data.mdb and lock.mdb in 0i0/
+   *  3. rollover to new epoch (second call to u3_disk_epoc_init())
+   *     a. same as 1a-g but also copies current snapshot between c/d steps
+   *  4. delete backup snapshot (c3_unlink() and c3_rmdir() calls)
+   *  5. delete old data.mdb and lock.mdb files (c3_unlink() calls)
+   */
+
+  //  check if lock.mdb is readable in log directory
+  c3_o luk_o = c3n;
+  c3_c luk_c[8193];
+  snprintf(luk_c, sizeof(luk_c), "%s/lock.mdb", log_u->com_u->pax_c);
+  if ( 0 == access(luk_c, R_OK) ) {
+    luk_o = c3y;
+  }
+
+  fprintf(stderr, "disk: migrating disk to v%d format\r\n", U3D_VER1);
+
+  //  migrate existing pier which has either:
+  //  - not started the migration, or
+  //  - crashed before completing the migration
+
+  //  get first/last event numbers from pre-migrated lmdb
+  c3_d fir_d, las_d;
+  if ( c3n == u3_lmdb_gulf(log_u->mdb_u, &fir_d, &las_d) ) {
+    fprintf(stderr, "disk: failed to get first/last event numbers\r\n");
+    return c3n;
+  }
+
+  // ensure there's a current snapshot
+  if ( eve_d != las_d ) {
+    fprintf(stderr, "disk: snapshot is out of date, please "
+                    "start/shutdown your pier gracefully first\r\n");
+    fprintf(stderr, "disk: eve_d (%" PRIc3_d ") != las_d (%" PRIc3_d ")\r\n",
+                    eve_d, las_d);
+    return c3n;
+  }
+
+  //  initialize first epoch "0i0"
+  if ( c3n == u3_disk_epoc_init(log_u, 0) ) {
+    fprintf(stderr, "disk: failed to initialize first epoch\r\n");
+    return c3n;
+  }
+
+  //  create hard links to data.mdb and lock.mdb in 0i0/
+  c3_c epo_c[8193], dut_c[8193], dat_c[8193], lok_c[8193];
+  snprintf(epo_c, sizeof(epo_c), "%s/0i0", log_u->com_u->pax_c);
+  snprintf(dut_c, sizeof(dut_c), "%s/data.mdb", log_u->com_u->pax_c);
+  snprintf(dat_c, sizeof(dat_c), "%s/data.mdb", epo_c);
+  snprintf(lok_c, sizeof(lok_c), "%s/lock.mdb", epo_c);
+
+  if ( 0 < c3_link(dut_c, dat_c) ) {
+    fprintf(stderr, "disk: failed to create data.mdb hard link\r\n");
+    return c3n;
+  }
+  if ( c3y == luk_o ) {  //  only link lock.mdb if it exists
+    if ( 0 < c3_link(luk_c, lok_c) ) {
+      fprintf(stderr, "disk: failed to create lock.mdb hard link\r\n");
+      return c3n;
+    }
+  }
+
+  //  rollover to new epoch
+  if ( c3n == u3_disk_epoc_init(log_u, las_d) ) {
+    fprintf(stderr, "disk: failed to initialize new epoch\r\n");
+    return c3n;
+  }
+
+  //  delete backup snapshot
+  c3_c bhk_c[8193], nop_c[8193], sop_c[8193];
+  snprintf(bhk_c, sizeof(bhk_c), "%s/.urb/bhk", u3_Host.dir_c);
+  snprintf(nop_c, sizeof(nop_c), "%s/north.bin", bhk_c);
+  snprintf(sop_c, sizeof(sop_c), "%s/south.bin", bhk_c);
+  if ( c3_unlink(nop_c) ) {
+    fprintf(stderr, "disk: failed to delete bhk/north.bin: %s\r\n",
+                    strerror(errno));
+  }
+  else if ( c3_unlink(sop_c) ) {
+    fprintf(stderr, "disk: failed to delete bhk/south.bin: %s\r\n",
+                    strerror(errno));
+  }
+  else {
+    if ( c3_rmdir(bhk_c) ) {
+      fprintf(stderr, "disk: failed to delete bhk/: %s\r\n",
+                      strerror(errno));
+    }
+  }
+
+  //  delete old lock.mdb and data.mdb files
+  if ( c3_unlink(luk_c) ) {
+    fprintf(stderr, "disk: failed to unlink lock.mdb: %s\r\n",
+                    strerror(errno));
+  }
+  if ( c3_unlink(dut_c) ) {
+    fprintf(stderr, "disk: failed to unlink data.mdb: %s\r\n",
+                    strerror(errno));
+    return c3n;  //  migration succeeds only if we can unlink data.mdb
+  }
+
+  //  success
+  fprintf(stderr, "disk: migrated disk to v%d format\r\n", U3D_VER1);
+
+  return c3y;
+}
+
+/* _disk_vere_diff(): checks if vere version mismatches latest epoch's.
+*/
+static c3_o
+_disk_vere_diff(u3_disk* log_u)
+{
+  c3_c ver_c[128];
+
+  if ( c3n == _disk_epoc_meta(log_u, log_u->epo_d, "vere",
+                             sizeof(ver_c) - 1, ver_c) )
+  {
+    return c3y; // assume mismatch if we can't read version
+  }
+
+  if ( 0 != strcmp(ver_c, URBIT_VERSION) ) {
+    return c3y;
+  }
+
+  return c3n;
+}
+
+/* u3_disk_kindly(): do the needful.
+*/
+void
+u3_disk_kindly(u3_disk* log_u, c3_d eve_d)
+{
+  if ( c3y == _disk_need_migrate(log_u) ) {
+    if ( c3n == _disk_migrate(log_u, eve_d) ) {
+      fprintf(stderr, "disk: failed to migrate event log\r\n");
+      exit(1);
+    }
+  }
+  else if ( c3y == _disk_vere_diff(log_u) ) {
+    if ( c3n == u3_disk_epoc_init(log_u, log_u->dun_d) ) {
+      fprintf(stderr, "disk: failed to initialize epoch\r\n");
+      exit(1);
+    }
+  }
+}
+
+typedef enum {
+  _epoc_good = 0,  // load successfully
+  _epoc_gone = 1,  // version missing, total failure
+  _epoc_fail = 2,  // transient failure (?)
+  _epoc_void = 3,  // empty event log (cheaper to recover?)
+  _epoc_late = 4   // format from the future
+} _epoc_kind;
+
+/* _disk_epoc_load(): load existing epoch, enumerating failures
+*/
+static _epoc_kind
+_disk_epoc_load(u3_disk* log_u, c3_d lat_d)
+{
+  //  check latest epoc version
+  //
+  {
+    c3_c ver_c[8];
+    c3_w ver_w;
+    if ( c3n == _disk_epoc_meta(log_u, lat_d, "epoc",
+                                sizeof(ver_c) - 1, ver_c) )
+    {
+      fprintf(stderr, "disk: failed to load epoch 0i%" PRIc3_d " version\r\n",
+                      lat_d);
+
+      return _epoc_gone;
+    }
+
+    if ( 1 != sscanf(ver_c, "%d", &ver_w) ) {
+      fprintf(stderr, "disk: failed to parse epoch version: '%s'\r\n", ver_c);
+      return _epoc_fail;
+    }
+
+    if ( U3D_VER1 != ver_w ) {
+      fprintf(stderr, "disk: unknown epoch version: '%s', expected '%d'\r\n",
+                      ver_c, U3D_VER1);
+      return _epoc_late;
+    }
+
+    log_u->ver_w = ver_w;
+  }
+
+  //  set path to latest epoch
+  c3_c epo_c[8193];
+  snprintf(epo_c, 8192, "%s/0i%" PRIc3_d, log_u->com_u->pax_c, lat_d);
+
+  //  initialize latest epoch's db
+  if ( 0 == (log_u->mdb_u = u3_lmdb_init(epo_c, siz_i)) ) {
+    fprintf(stderr, "disk: failed to initialize database at %s\r\n",
+                    epo_c);
+    return _epoc_fail;
+  }
+
+  fprintf(stderr, "disk: loaded epoch 0i%" PRIc3_d "\r\n", lat_d);
+
+  //  get first/last event numbers from lmdb
+  c3_d fir_d, las_d;
+  if ( c3n == u3_lmdb_gulf(log_u->mdb_u, &fir_d, &las_d) ) {
+    fprintf(stderr, "disk: failed to get first/last event numbers\r\n");
+    u3_lmdb_exit(log_u->mdb_u);
+    log_u->mdb_u = 0;
+    return _epoc_fail;
+  }
+
+  if (  (c3n == u3_Host.ops_u.nuu )
+     && !fir_d
+     && !las_d
+     && (c3n == u3_disk_read_meta(log_u->mdb_u, 0, 0, 0)) )
+  {
+    u3_lmdb_exit(log_u->mdb_u);
+    log_u->mdb_u = 0;
+    return _epoc_void;
+  }
+
+  //  initialize dun_d/sen_d values
+  log_u->dun_d = ( 0 != las_d ) ? las_d : lat_d;
+  log_u->sen_d = log_u->dun_d;
+
+  return _epoc_good;
+}
+
 /* u3_disk_init(): load or create pier directories and event log.
 */
 u3_disk*
@@ -1019,66 +1606,153 @@ u3_disk_init(c3_c* pax_c, u3_disk_cb cb_u)
     c3_free(dir_c);
   }
 
-  //  create/load $pier/.urb/log, initialize db
+  //  create/load $pier/.urb/log
   //
   {
-    c3_c* log_c = c3_malloc(10 + strlen(pax_c));
-
-    strcpy(log_c, pax_c);
-    strcat(log_c, "/.urb/log");
+    c3_c log_c[8193];
+    snprintf(log_c, sizeof(log_c), "%s/.urb/log", pax_c);
 
     if ( 0 == (log_u->com_u = u3_foil_folder(log_c)) ) {
       fprintf(stderr, "disk: failed to load /.urb/log in %s\r\n", pax_c);
-      c3_free(log_c);
       c3_free(log_u);
       return 0;
     }
 
-    //  Arbitrarily choosing 1TB as a "large enough" mapsize
-    //
-    //  per the LMDB docs:
-    //  "[..] on 64-bit there is no penalty for making this huge (say 1TB)."
+    //  if fresh boot, initialize disk v1
     //
-    {
-      const size_t siz_i =
-      // 500 GiB is as large as musl on aarch64 wants to allow
-      #if (defined(U3_CPU_aarch64) && defined(U3_OS_linux))
-        0x7d00000000;
-      #else
-        0x10000000000;
-      #endif
+    if ( c3y == u3_Host.ops_u.nuu ) {
+      //  initialize first epoch "0i0"
+      if ( c3n == u3_disk_epoc_init(log_u, 0) ) {
+        fprintf(stderr, "disk: failed to initialize first epoch\r\n");
+        return 0;
+      }
+    }
+    else if ( c3y == _disk_need_migrate(log_u) ) {
+      fprintf(stderr, "disk: loading old format\r\n");
 
       if ( 0 == (log_u->mdb_u = u3_lmdb_init(log_c, siz_i)) ) {
-        fprintf(stderr, "disk: failed to initialize database\r\n");
-        c3_free(log_c);
+        fprintf(stderr, "disk: failed to initialize lmdb\r\n");
+        c3_free(log_u);
+      }
+
+      c3_d fir_d;
+      if ( c3n == u3_lmdb_gulf(log_u->mdb_u, &fir_d, &log_u->dun_d) ) {
+        fprintf(stderr, "disk: failed to load latest event from lmdb\r\n");
+        // XX dispose mdb_u
         c3_free(log_u);
         return 0;
       }
-    }
 
-    c3_free(log_c);
-  }
+      //  if a top-level log exists but is empty it's safe to remove.
+      //  for extra safety, we only do this if we also have epochs.
+      //  (the top-level log was most likely created by vere downgrade)
+      //
+      c3_d nop_d;
+      if (  !fir_d
+         && !log_u->dun_d
+         && (c3y == u3_disk_epoc_last(log_u, &nop_d)) )
+      {
+        c3_c luk_c[8193]; c3_c dut_c[8193];
+        snprintf(dut_c, sizeof(dut_c), "%s/data.mdb", log_c);
+        snprintf(luk_c, sizeof(luk_c), "%s/lock.mdb", log_u->com_u->pax_c);
+
+        u3_lmdb_exit(log_u->mdb_u);
+        log_u->mdb_u = 0;
+
+        if ( c3_unlink(dut_c)
+           ||  (  (0 == access(luk_c, R_OK))
+               && c3_unlink(luk_c) ))
+        {
+          fprintf(stderr, "disk: failed to unlink empty, old log\r\n");
+        }
 
-  //  get the latest event number from the db
-  //
-  {
-    log_u->dun_d = 0;
-    c3_d fir_d;
+        //  continue to epoc initialization
+      }
 
-    if ( c3n == u3_lmdb_gulf(log_u->mdb_u, &fir_d, &log_u->dun_d) ) {
-      fprintf(stderr, "disk: failed to load latest event from database\r\n");
+      else {
+        log_u->sen_d = log_u->dun_d;
+        log_u->ver_w = 0;
+
+        return log_u;
+      }
+    }
+
+    //  get latest epoch number
+    c3_d lat_d;
+    if ( c3n == u3_disk_epoc_last(log_u, &lat_d) ) {
+      fprintf(stderr, "disk: failed to load epoch number\r\n");
       c3_free(log_u);
       return 0;
     }
 
-    log_u->sen_d = log_u->dun_d;
-  }
+    c3_o try_o = c3n;
+
+try_init:
+    {
+      _epoc_kind kin_e = _disk_epoc_load(log_u, lat_d);
+
+      switch ( kin_e ) {
+        case _epoc_good: {
+          //  mark the latest epoch directory
+          log_u->epo_d = lat_d;
 
-  log_u->liv_o = c3y;
+          //  mark the log as live
+          log_u->liv_o = c3y;
 
 #if defined(DISK_TRACE_JAM) || defined(DISK_TRACE_CUE)
-  u3t_trace_open(pax_c);
+          u3t_trace_open(pax_c);
 #endif
 
-  return log_u;
+          return log_u;
+        } break;
+
+        case _epoc_void: // XX could handle more efficiently
+
+        case _epoc_gone: {
+          // XX if there is no version number, the epoc is invalid
+          // backup and try previous
+
+          if ( c3y == try_o ) {
+            fprintf(stderr, "multiple bad epochs, bailing out\r\n");
+            c3_free(log_u);
+            return 0;
+          }
+
+          c3_z len_z = u3_disk_epoc_list(log_u, 0);
+
+          if ( len_z <= 1 ) {
+            fprintf(stderr, "only epoch is bad, bailing out\r\n");
+            c3_free(log_u);
+            return 0;
+          }
+
+          c3_d* sot_d = c3_malloc(len_z * sizeof(*sot_d));
+          u3_disk_epoc_list(log_u, sot_d);
+
+          fprintf(stderr, "disk: latest epoch is 0i%" PRIc3_d " is bogus; "
+                          "falling back to previous at 0i%" PRIc3_d "\r\n",
+                          lat_d, sot_d[1]);
+
+          u3_disk_epoc_kill(log_u, lat_d);
+
+          lat_d = sot_d[1];
+          try_o = c3y;
+          c3_free(sot_d);
+          goto try_init;
+        } break;
+
+        case _epoc_fail: {
+          fprintf(stderr, "failed to load epoch\r\n");
+          c3_free(log_u);
+          return 0;
+        } break;
+
+        case _epoc_late: {
+          fprintf(stderr, "upgrade runtime version\r\n");
+          c3_free(log_u);
+          return 0;
+        }
+      }
+    }
+  }
 }
diff --git a/pkg/vere/foil.c b/pkg/vere/foil.c
index 26ff8b3d04..9fae86973f 100644
--- a/pkg/vere/foil.c
+++ b/pkg/vere/foil.c
@@ -106,13 +106,17 @@ u3_foil_folder(const c3_c* pax_c)
     dir_u = u3_dire_init(pax_c);
   }
 
-  /*  create entries for all files
+  /*  create entries for all files and directories
   */
   while ( UV_EOF != uv_fs_scandir_next(&ruq_u, &den_u) ) {
     if ( UV_DIRENT_FILE == den_u.type ) {
       u3_dent* det_u = u3_dent_init(den_u.name);
       det_u->nex_u = dir_u->all_u;
       dir_u->all_u = det_u;
+    } else if ( UV_DIRENT_DIR == den_u.type ) {
+      u3_dent* det_u = u3_dent_init(den_u.name);
+      det_u->nex_u = dir_u->dil_u;
+      dir_u->dil_u = det_u;
     }
   }
 
diff --git a/pkg/vere/io/ames.c b/pkg/vere/io/ames.c
index 24baa6e042..6df308239b 100644
--- a/pkg/vere/io/ames.c
+++ b/pkg/vere/io/ames.c
@@ -1030,17 +1030,9 @@ _ames_czar_cb(uv_getaddrinfo_t* adr_u,
     struct addrinfo* rai_u = aif_u;
     time_t             now = time(0);
 
-    while ( rai_u ) {
-      if ( (AF_INET == rai_u->ai_family) ) {
-        _ames_czar_here(pac_u, now, (struct sockaddr_in *)rai_u->ai_addr);
-        break;
-      }
-      else {
-        rai_u = rai_u->ai_next;
-      }
-    }
-
-    if ( !rai_u ) {
+    if ( sas_i == 0 ) {
+      _ames_czar_here(pac_u, now, (struct sockaddr_in *)rai_u->ai_addr);
+    } else {
       _ames_czar_gone(pac_u, now);
     }
   }
@@ -1128,9 +1120,13 @@ _ames_czar(u3_pact* pac_u)
         uv_getaddrinfo_t* adr_u = c3_malloc(sizeof(*adr_u));
         adr_u->data = pac_u;
 
+        struct addrinfo hints;
+        memset(&hints, 0, sizeof(hints));
+        hints.ai_family = AF_INET; // only IPv4 addresses
+
         if ( 0 != (sas_i = uv_getaddrinfo(u3L, adr_u,
                                           _ames_czar_cb,
-                                          pac_u->rut_u.dns_c, 0, 0)) )
+                                          pac_u->rut_u.dns_c, 0, &hints)) )
         {
           u3l_log("ames: %s", uv_strerror(sas_i));
           _ames_czar_gone(pac_u, now);
diff --git a/pkg/vere/lord.c b/pkg/vere/lord.c
index cf1dfcfba9..a63824ae9b 100644
--- a/pkg/vere/lord.c
+++ b/pkg/vere/lord.c
@@ -1160,10 +1160,11 @@ u3_lord_init(c3_c* pax_c, c3_w wag_w, c3_d key_d[4], u3_lord_cb cb_u)
   //  spawn new process and connect to it
   //
   {
-    c3_c* arg_c[11];
+    c3_c* arg_c[12];
     c3_c  key_c[256];
     c3_c  wag_c[11];
     c3_c  hap_c[11];
+    c3_c  per_c[11];
     c3_c  cev_c[11];
     c3_c  lom_c[11];
     c3_c  tos_c[11];
@@ -1179,6 +1180,8 @@ u3_lord_init(c3_c* pax_c, c3_w wag_w, c3_d key_d[4], u3_lord_cb cb_u)
 
     sprintf(hap_c, "%u", u3_Host.ops_u.hap_w);
 
+    sprintf(per_c, "%u", u3_Host.ops_u.per_w);
+
     sprintf(lom_c, "%u", u3_Host.ops_u.lom_y);
 
     sprintf(tos_c, "%u", u3C.tos_w);
@@ -1208,7 +1211,8 @@ u3_lord_init(c3_c* pax_c, c3_w wag_w, c3_d key_d[4], u3_lord_cb cb_u)
     }
 
     arg_c[9] = tos_c;
-    arg_c[10] = NULL;
+    arg_c[10] = per_c;
+    arg_c[11] = NULL;
 
     uv_pipe_init(u3L, &god_u->inn_u.pyp_u, 0);
     uv_timer_init(u3L, &god_u->out_u.tim_u);
diff --git a/pkg/vere/main.c b/pkg/vere/main.c
index f83d656e98..930d8981ad 100644
--- a/pkg/vere/main.c
+++ b/pkg/vere/main.c
@@ -183,6 +183,9 @@ _main_init(void)
   u3_Host.ops_u.veb = c3n;
   u3_Host.ops_u.puf_c = "jam";
   u3_Host.ops_u.hap_w = 50000;
+  u3C.hap_w = u3_Host.ops_u.hap_w;
+  u3_Host.ops_u.per_w = 50000;
+  u3C.per_w = u3_Host.ops_u.per_w;
   u3_Host.ops_u.kno_w = DefaultKernel;
 
   u3_Host.ops_u.sap_w = 120;    /* aka 2 minutes */
@@ -247,6 +250,7 @@ _main_getopt(c3_i argc, c3_c** argv)
     { "loom",                required_argument, NULL, c3__loom },
     { "local",               no_argument,       NULL, 'L' },
     { "lite-boot",           no_argument,       NULL, 'l' },
+    { "keep-cache-limit",    required_argument, NULL, 'M' },
     { "replay-to",           required_argument, NULL, 'n' },
     { "profile",             no_argument,       NULL, 'P' },
     { "ames-port",           required_argument, NULL, 'p' },
@@ -279,7 +283,7 @@ _main_getopt(c3_i argc, c3_c** argv)
   };
 
   while ( -1 != (ch_i=getopt_long(argc, argv,
-                 "A:B:C:DF:G:H:I:J:K:LPRSX:Y:Z:ab:c:de:gi:jk:ln:p:qr:stu:vw:x",
+                 "A:B:C:DF:G:H:I:J:K:LM:PRSX:Y:Z:ab:c:de:gi:jk:ln:p:qr:stu:vw:x",
                  lop_u, &lid_i)) )
   {
     switch ( ch_i ) {
@@ -342,7 +346,7 @@ _main_getopt(c3_i argc, c3_c** argv)
           return c3n;
         } else {
           u3_Host.ops_u.sap_w = arg_w * 60;
-          if ( 0 == u3_Host.ops_u.sap_w) 
+          if ( 0 == u3_Host.ops_u.sap_w )
             return c3n;
         }
         break;
@@ -365,6 +369,7 @@ _main_getopt(c3_i argc, c3_c** argv)
         if ( c3n == _main_readw(optarg, 1000000000, &u3_Host.ops_u.hap_w) ) {
           return c3n;
         }
+        u3C.hap_w = u3_Host.ops_u.hap_w;
         break;
       }
       case 'c': {
@@ -412,6 +417,13 @@ _main_getopt(c3_i argc, c3_c** argv)
         u3_Host.ops_u.key_c = _main_repath(optarg);
         break;
       }
+      case 'M': {
+        if ( c3n == _main_readw(optarg, 1000000000, &u3_Host.ops_u.per_w) ) {
+          return c3n;
+        }
+        u3C.per_w = u3_Host.ops_u.per_w;
+        break;
+      }
       case 'n': {
         u3_Host.ops_u.til_c = strdup(optarg);
         break;
@@ -712,6 +724,7 @@ _cw_usage(c3_c* bin_c)
     "  %s next %.*s              request upgrade:\n",
     "  %s queu %.*s<at-event>    cue state:\n",
     "  %s chop %.*s              truncate event log:\n",
+    "  %s roll %.*s              rollover to new epoch:\n",
     "  %s vere ARGS <output dir>    download binary:\n",
     "\n  run as a 'serf':\n",
     "    %s serf <pier> <key> <flags> <cache-size> <at-event>"
@@ -764,6 +777,7 @@ u3_ve_usage(c3_i argc, c3_c** argv)
     "-L, --local                   Local networking only\n",
     "    --loom                    Set loom to binary exponent (31 == 2GB)\n"
     "-l, --lite-boot               Most-minimal startup\n",
+    "-M, --keep-cache-limit LIMIT  Set persistent memo cache max size; 0 means default\n",
     "-n, --replay-to NUMBER        Replay up to event\n",
     "-P, --profile                 Profiling\n",
     "-p, --ames-port PORT          Set the ames port to bind to\n",
@@ -1075,6 +1089,8 @@ _cw_serf_commence(c3_i argc, c3_c* argv[])
     exit(1);
   }
 
+  //  XX use named arguments and getopt
+
   c3_d       eve_d = 0;
   uv_loop_t* lup_u = u3_Host.lup_u = uv_default_loop();
   c3_c*      dir_c = argv[2];
@@ -1086,6 +1102,7 @@ _cw_serf_commence(c3_i argc, c3_c* argv[])
   c3_c*      eve_c = argv[7];
   c3_c*      eph_c = argv[8];
   c3_c*      tos_c = argv[9];
+  c3_c*      per_c = argv[10];
   c3_w       tos_w;
 
   _cw_init_io(lup_u);
@@ -1110,7 +1127,8 @@ _cw_serf_commence(c3_i argc, c3_c* argv[])
     //  XX check return
     //
     sscanf(wag_c, "%" SCNu32, &u3C.wag_w);
-    sscanf(hap_c, "%" SCNu32, &u3_Host.ops_u.hap_w);
+    sscanf(hap_c, "%" SCNu32, &u3C.hap_w);
+    sscanf(per_c, "%" SCNu32, &u3C.per_w);
     sscanf(lom_c, "%" SCNu32, &lom_w);
 
     if ( 1 != sscanf(tos_c, "%" SCNu32, &u3C.tos_w) ) {
@@ -1560,11 +1578,11 @@ _cw_info(c3_i argc, c3_c* argv[])
     exit(1);
   }
 
-  c3_d     eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+  u3_Host.eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
   u3_disk* log_u = _cw_disk_init(u3_Host.dir_c);
 
   fprintf(stderr, "\r\nurbit: %s at event %" PRIu64 "\r\n",
-                  u3_Host.dir_c, eve_d);
+                  u3_Host.dir_c, u3_Host.eve_d);
 
   u3_disk_slog(log_u);
   printf("\n");
@@ -1719,17 +1737,17 @@ _cw_cram(c3_i argc, c3_c* argv[])
     exit(1);
   }
 
-  c3_d     eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+  u3_Host.eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
   u3_disk* log_u = _cw_disk_init(u3_Host.dir_c); // XX s/b try_aquire lock
   c3_o  ret_o;
 
   fprintf(stderr, "urbit: cram: preparing\r\n");
 
-  if ( c3n == (ret_o = u3u_cram(u3_Host.dir_c, eve_d)) ) {
+  if ( c3n == (ret_o = u3u_cram(u3_Host.dir_c, u3_Host.eve_d)) ) {
     fprintf(stderr, "urbit: cram: unable to jam state\r\n");
   }
   else {
-    fprintf(stderr, "urbit: cram: rock saved at event %" PRIu64 "\r\n", eve_d);
+    fprintf(stderr, "urbit: cram: rock saved at event %" PRIu64 "\r\n", u3_Host.eve_d);
   }
 
   //  save even on failure, as we just did all the work of deduplication
@@ -1831,12 +1849,11 @@ _cw_queu(c3_i argc, c3_c* argv[])
     exit(1);
   }
   else {
+    u3_Host.eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
     u3_disk* log_u = _cw_disk_init(u3_Host.dir_c); // XX s/b try_aquire lock
 
     fprintf(stderr, "urbit: queu: preparing\r\n");
 
-    u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
-
     //  XX can spuriously fail do to corrupt memory-image checkpoint,
     //  need a u3m_half_boot equivalent
     //  workaround is to delete/move the checkpoint in case of corruption
@@ -1924,10 +1941,10 @@ _cw_meld(c3_i argc, c3_c* argv[])
     exit(1);
   }
 
-  u3_disk* log_u = _cw_disk_init(u3_Host.dir_c); // XX s/b try_aquire lock
-
   u3C.wag_w |= u3o_hashless;
-  u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+
+  u3_Host.eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+  u3_disk* log_u = _cw_disk_init(u3_Host.dir_c); // XX s/b try_aquire lock
 
   u3a_print_memory(stderr, "urbit: meld: gained", u3u_meld());
 
@@ -2086,9 +2103,9 @@ _cw_pack(c3_i argc, c3_c* argv[])
     exit(1);
   }
 
+  u3_Host.eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
   u3_disk* log_u = _cw_disk_init(u3_Host.dir_c); // XX s/b try_aquire lock
 
-  u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
   u3a_print_memory(stderr, "urbit: pack: gained", u3m_pack());
 
   u3m_save();
@@ -2105,6 +2122,38 @@ _cw_play_slog(u3_noun hod)
   u3z(hod);
 }
 
+/* _cw_play_snap(): prepare snapshot for full replay.
+*/
+static void
+_cw_play_snap(u3_disk* log_u)
+{
+  c3_c chk_c[8193], epo_c[8193];
+  snprintf(chk_c, 8193, "%s/.urb/chk", u3_Host.dir_c);
+  snprintf(epo_c, 8192, "%s/0i%" PRIc3_d, log_u->com_u->pax_c, log_u->epo_d);
+
+  if ( 0 == log_u->epo_d ) {
+    //  if epoch 0 is the latest, delete the snapshot files in chk/
+    c3_c nor_c[8193], sop_c[8193];
+    snprintf(nor_c, 8193, "%s/.urb/chk/north.bin", u3_Host.dir_c);
+    snprintf(sop_c, 8193, "%s/.urb/chk/south.bin", u3_Host.dir_c);
+    if ( c3_unlink(nor_c) && (ENOENT != errno) ) {
+      fprintf(stderr, "mars: failed to unlink %s: %s\r\n",
+                      nor_c, strerror(errno));
+      exit(1);
+    }
+    if ( c3_unlink(sop_c) && (ENOENT != errno) ) {
+      fprintf(stderr, "mars: failed to unlink %s: %s\r\n",
+                      sop_c, strerror(errno));
+      exit(1);
+    }
+  }
+  else if ( 0 != u3e_backup(epo_c, chk_c, c3y) ) {
+    //  copy the latest epoch's snapshot files into chk/
+    fprintf(stderr, "mars: failed to copy snapshot\r\n");
+    exit(1);
+  }
+}
+
 /* _cw_play_exit(): exit immediately.
 */
 static void
@@ -2116,6 +2165,68 @@ _cw_play_exit(c3_i int_i)
   raise(SIGINT);
 }
 
+/* _cw_play_impl(): replay events, but better.
+*/
+static c3_d
+_cw_play_impl(c3_d eve_d, c3_d sap_d, c3_o mel_o, c3_o sof_o, c3_o ful_o)
+{
+  c3_d pay_d;
+
+  //  XX handle SIGTSTP so that the lockfile is not orphaned?
+  //
+  u3_disk* log_u = _cw_disk_init(u3_Host.dir_c);
+
+  //  Handle SIGTSTP as if it was SIGINT.
+  //
+  //    Configured here using signal() so as to be immediately available.
+  //
+  signal(SIGTSTP, _cw_play_exit);
+
+  //  XX source these from a shared struct ops_u
+  if ( c3y == mel_o ) {
+    u3C.wag_w |= u3o_auto_meld;
+  }
+
+  if ( c3y == sof_o ) {
+    u3C.wag_w |= u3o_soft_mugs;
+  }
+
+  u3C.wag_w |= u3o_hashless;
+
+  if ( c3y == ful_o ) {
+    u3l_log("mars: preparing for full replay");
+    _cw_play_snap(log_u);
+  }
+
+  //  XX this should check that snapshot is within epoc,
+  //  and load from the epoc / reboot if it is not
+  //
+  u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+
+  u3C.slog_f = _cw_play_slog;
+
+  {
+    u3_mars mar_u = {
+      .log_u = log_u,
+      .dir_c = u3_Host.dir_c,
+      .sen_d = u3A->eve_d,
+      .dun_d = u3A->eve_d,
+    };
+
+    pay_d = u3_mars_play(&mar_u, eve_d, sap_d);
+    u3_Host.eve_d = mar_u.dun_d;
+
+    //  migrate or rollover as needed
+    //
+    u3_disk_kindly(log_u, u3_Host.eve_d);
+  }
+
+  u3_disk_exit(log_u);
+  u3m_stop();
+
+  return pay_d;
+}
+
 /* _cw_play(): replay events, but better.
 */
 static void
@@ -2208,55 +2319,9 @@ _cw_play(c3_i argc, c3_c* argv[])
     exit(1);
   }
 
-  //  XX handle SIGTSTP so that the lockfile is not orphaned?
-  //
-  u3_disk* log_u = _cw_disk_init(u3_Host.dir_c); // XX s/b try_aquire lock
-
-  //  Handle SIGTSTP as if it was SIGINT.
-  //
-  //    Configured here using signal() so as to be immediately available.
-  //
-  signal(SIGTSTP, _cw_play_exit);
-
-  if ( c3y == mel_o ) {
-    u3C.wag_w |= u3o_auto_meld;
-  }
-
-  if ( c3y == sof_o ) {
-    u3C.wag_w |= u3o_soft_mugs;
-  }
-
-  u3C.wag_w |= u3o_hashless;
-
-  //  XX this should restore the epoch snapshot and replay that
-  //
-  if ( c3y == ful_o ) {
-    u3l_log("mars: preparing for full replay");
-    u3m_init((size_t)1 << u3_Host.ops_u.lom_y);
-    u3e_live(c3n, u3_Host.dir_c);
-    u3m_foul();
-    u3m_pave(c3y);
-    u3j_boot(c3y);
-  }
-  else {
-    u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
-  }
-
-  u3C.slog_f = _cw_play_slog;
-
-  {
-    u3_mars mar_u = {
-      .log_u = log_u,
-      .dir_c = u3_Host.dir_c,
-      .sen_d = u3A->eve_d,
-      .dun_d = u3A->eve_d,
-    };
-
-    u3_mars_play(&mar_u, eve_d, sap_d);
+  if ( !_cw_play_impl(eve_d, sap_d, mel_o, sof_o, ful_o) ) {
+    fprintf(stderr, "mars: nothing to do!");
   }
-
-  u3_disk_exit(log_u);
-  u3m_stop();
 }
 
 /* _cw_prep(): prepare for upgrade
@@ -2264,6 +2329,8 @@ _cw_play(c3_i argc, c3_c* argv[])
 static void
 _cw_prep(c3_i argc, c3_c* argv[])
 {
+  //  XX roll with old binary
+  //     check that new epoch is empty, migrate snapshot in-place
   c3_i ch_i, lid_i;
   c3_w arg_w;
 
@@ -2404,123 +2471,138 @@ _cw_chop(c3_i argc, c3_c* argv[])
   }
 
   // gracefully shutdown the pier if it's running
-  u3_disk* old_u = _cw_disk_init(u3_Host.dir_c);
+  u3_Host.eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+  u3_disk* log_u = _cw_disk_init(u3_Host.dir_c);
 
-  // note: this include patch applications (if any)
-  u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+  u3_disk_kindly(log_u, u3_Host.eve_d);
 
-  // check if there's a *current* snapshot
-  if ( old_u->dun_d != u3A->eve_d ) {
-    fprintf(stderr, "chop: error: snapshot is out of date, please "
-                    "start/shutdown your pier gracefully first\r\n");
-    fprintf(stderr, "chop: eve_d: %" PRIu64 ", dun_d: %" PRIu64 "\r\n", u3A->eve_d, old_u->dun_d);
+  //  create new epoch
+  c3_d fir_d, las_d;
+  if ( c3n == u3_lmdb_gulf(log_u->mdb_u, &fir_d, &las_d) ) {
+    fprintf(stderr, "chop: failed to get first/last events\r\n");
     exit(1);
   }
 
-  if ( c3n == u3m_backup(c3y)) {  //  backup current snapshot
-    fprintf(stderr, "chop: error: failed to backup snapshot\r\n");
+  //  create new epoch if latest isn't empty
+  if ( (fir_d != las_d) && (c3n == u3_disk_epoc_init(log_u, las_d)) ) {
+    fprintf(stderr, "chop: failed to create new epoch\r\n");
     exit(1);
   }
 
-  // initialize the lmdb environment
-  // see disk.c:885
-  const size_t siz_i =
-  // 500 GiB is as large as musl on aarch64 wants to allow
-  #if (defined(U3_CPU_aarch64) && defined(U3_OS_linux))
-    0x7d00000000;
-  #else
-    0x10000000000;
-  #endif
-  c3_c log_c[8193];
-  snprintf(log_c, sizeof(log_c), "%s/.urb/log", u3_Host.dir_c);
+  c3_z len_z = u3_disk_epoc_list(log_u, 0);
 
-  // get the first/last event numbers from the event log
-  c3_d fir_d, las_d;
-  if ( c3n == u3_lmdb_gulf(old_u->mdb_u, &fir_d, &las_d) ) {
-    fprintf(stderr, "chop: failed to load latest event from database\r\n");
-    exit(1);
+  if ( len_z <= 2 ) {
+    fprintf(stderr, "chop: nothing to do, have a great day\r\n");
+    exit(0);  //  enjoy
   }
 
-  // get the metadata
-  c3_d     who_d[2];
-  c3_o     fak_o;
-  c3_w     lif_w;
-  if ( c3y != u3_disk_read_meta(old_u->mdb_u, who_d, &fak_o, &lif_w) ) {
-    fprintf(stderr, "chop: failed to read metadata\r\n");
-    exit(1);
-  }
+  c3_d* sot_d = c3_malloc(len_z * sizeof(c3_d));
+  u3_disk_epoc_list(log_u, sot_d);
 
-  // get the last event
-  u3_lmdb_walk itr_u;
-  size_t       len_i;
-  void*        buf_v[1];
-  if ( c3n == u3_lmdb_walk_init(old_u->mdb_u, &itr_u, las_d, las_d) ) {
-    fprintf(stderr, "chop: failed to initialize iterator\r\n");
-    exit(1);
+  //  delete all but the last two epochs
+  //
+  //    XX parameterize the number of epochs to chop
+  //
+  for ( c3_z i_z = 2; i_z < len_z; i_z++ ) {
+    fprintf(stderr, "chop: deleting epoch 0i%" PRIc3_d "\r\n", sot_d[i_z]);
+    if ( c3y != u3_disk_epoc_kill(log_u, sot_d[i_z]) ) {
+      fprintf(stderr, "chop: failed to delete epoch 0i%" PRIu64 "\r\n", sot_d[i_z]);
+      exit(1);
+    }
   }
-  if ( c3n == u3_lmdb_walk_next(&itr_u, &len_i, buf_v) ) {
-    fprintf(stderr, "chop: failed to read event\r\n");
-    exit(1);
+
+  // cleanup
+  c3_free(sot_d);
+  u3_disk_exit(log_u);
+
+  // success
+  fprintf(stderr, "chop: event log truncation complete\r\n");
+}
+
+/* _cw_roll(): rollover to new epoch
+ */
+static void
+_cw_roll(c3_i argc, c3_c* argv[])
+{
+  c3_i ch_i, lid_i;
+  c3_w arg_w;
+
+  static struct option lop_u[] = {
+    { "loom", required_argument, NULL, c3__loom },
+    { NULL, 0, NULL, 0 }
+  };
+
+  u3_Host.dir_c = _main_pier_run(argv[0]);
+
+  while ( -1 != (ch_i=getopt_long(argc, argv, "", lop_u, &lid_i)) ) {
+    switch ( ch_i ) {
+      case c3__loom: {
+        if (_main_readw_loom("loom", &u3_Host.ops_u.lom_y)) {
+          exit(1);
+        }
+      } break;
+
+      case '?': {
+        fprintf(stderr, "invalid argument\r\n");
+        exit(1);
+      } break;
+    }
   }
-  u3_lmdb_walk_done(&itr_u);
 
-  // initialize a fresh lmdb environment in the "chop" subdir
-  c3_c cho_c[8193];
-  snprintf(cho_c, sizeof(cho_c), "%s/chop", log_c);
-  if ( 0 != access(cho_c, F_OK) ) {
-    if ( 0 != c3_mkdir(cho_c, 0700) ) {
-      fprintf(stderr, "chop: failed to create chop directory\r\n");
+  //  argv[optind] is always "roll"
+  //
+
+  if ( !u3_Host.dir_c ) {
+    if ( optind + 1 < argc ) {
+      u3_Host.dir_c = argv[optind + 1];
+    }
+    else {
+      fprintf(stderr, "invalid command, pier required\r\n");
       exit(1);
     }
-  }
-  MDB_env* new_u = u3_lmdb_init(cho_c, siz_i);
-  if ( !new_u ) {
-    fprintf(stderr, "chop: failed to initialize new database\r\n");
-    exit(1);
+
+    optind++;
   }
 
-  // write the metadata to the database
-  if ( c3n == u3_disk_save_meta(new_u, who_d, fak_o, lif_w) ) {
-    fprintf(stderr, "chop: failed to save metadata\r\n");
+  if ( optind + 1 != argc ) {
+    fprintf(stderr, "invalid command\r\n");
     exit(1);
   }
 
-  // write the last event to the database
-  // warning: this relies on the old database still being open
-  if ( c3n == u3_lmdb_save(new_u, las_d, 1, buf_v, &len_i) ) {
-    fprintf(stderr, "chop: failed to write last event\r\n");
+  // gracefully shutdown the pier if it's running
+  u3_Host.eve_d = u3m_boot(u3_Host.dir_c, (size_t)1 << u3_Host.ops_u.lom_y);
+  u3_disk* log_u = _cw_disk_init(u3_Host.dir_c);
+
+  u3_disk_kindly(log_u, u3_Host.eve_d);
+
+  // check if there's a *current* snapshot
+  if ( log_u->dun_d != u3A->eve_d ) {
+    fprintf(stderr, "roll: error: snapshot is out of date, please "
+                    "start/shutdown your pier gracefully first\r\n");
+    fprintf(stderr, "roll: eve_d: %" PRIc3_d ", dun_d: %" PRIc3_d "\r\n", \
+                     u3A->eve_d, log_u->dun_d);
     exit(1);
   }
 
-  // backup the original database file
-  c3_c dat_c[8193], bak_c[8193];
-  snprintf(dat_c, sizeof(dat_c), "%s/data.mdb", log_c);
-  // "data_<first>-<last>.mdb.bak"
-  snprintf(bak_c, sizeof(bak_c), "%s/data_%" PRIu64 "-%" PRIu64 ".mdb.bak", cho_c, fir_d, las_d);
-  if ( 0 != c3_rename(dat_c, bak_c) ) {
-    fprintf(stderr, "chop: failed to backup original database file\r\n");
+  //  create new epoch
+  c3_d fir_d, las_d;
+  if ( c3n == u3_lmdb_gulf(log_u->mdb_u, &fir_d, &las_d) ) {
+    fprintf(stderr, "roll: failed to get first/last events\r\n");
     exit(1);
   }
 
-  // rename new database file to be official
-  c3_c new_c[8193];
-  snprintf(new_c, sizeof(new_c), "%s/data.mdb", cho_c);
-  if ( 0 != c3_rename(new_c, dat_c) ) {
-    fprintf(stderr, "chop: failed to rename new database file\r\n");
+  if ( fir_d == las_d ) {
+    fprintf(stderr, "roll: latest epoch already empty\r\n");
+    exit(0);
+  }
+  else if ( c3n == u3_disk_epoc_init(log_u, las_d) ) {
+    fprintf(stderr, "roll: failed to create new epoch\r\n");
     exit(1);
   }
 
-  // cleanup
-  u3_disk_exit(old_u);
-  u3_lmdb_exit(new_u);
-  u3m_stop();
-
-  // success
-  fprintf(stderr, "chop: event log truncation complete\r\n");
-  fprintf(stderr, "      event log backup written to %s\r\n", bak_c);
-  fprintf(stderr, "      WARNING: ENSURE YOU CAN RESTART YOUR SHIP BEFORE DELETING YOUR EVENT LOG BACKUP FILE!\r\n");
-  fprintf(stderr, "      if you can't, restore your log by running:\r\n");
-  fprintf(stderr, "      `mv %s %s` then try again\r\n", bak_c, dat_c);
+  //  success
+  c3_d epo_d = log_u->dun_d + 1;
+  fprintf(stderr, "roll: epoch rollover complete\r\n");
 }
 
 /* _cw_vere(): download vere
@@ -2806,6 +2888,7 @@ _cw_utils(c3_i argc, c3_c* argv[])
     case c3__prep: _cw_prep(argc, argv); return 2; // continue on
     case c3__queu: _cw_queu(argc, argv); return 1;
     case c3__chop: _cw_chop(argc, argv); return 1;
+    case c3__roll: _cw_roll(argc, argv); return 1;
     case c3__vere: _cw_vere(argc, argv); return 1;
     case c3__vile: _cw_vile(argc, argv); return 1;
 
@@ -2995,6 +3078,13 @@ main(c3_i   argc,
       }
     }
 
+    //  we need the current snapshot's latest event number to
+    //  validate whether we can execute disk migration
+    if ( u3_Host.ops_u.nuu == c3n ) {
+      _cw_play_impl(0, 0, c3n, c3n, c3n);
+      //  XX  unmap loom, else parts of the snapshot could be left in memory
+    }
+
     //  starting u3m configures OpenSSL memory functions, so we must do it
     //  before any OpenSSL allocations
     //
diff --git a/pkg/vere/mars.c b/pkg/vere/mars.c
index 37933bd49e..5e940182dc 100644
--- a/pkg/vere/mars.c
+++ b/pkg/vere/mars.c
@@ -6,6 +6,8 @@
 #include "noun.h"
 #include "types.h"
 #include "vere.h"
+#include "ivory.h"
+#include "ur.h"
 #include "db/lmdb.h"
 #include <mars.h>
 #include <stdio.h>
@@ -179,6 +181,29 @@ _mars_do_boot(u3_disk* log_u, c3_d eve_d)
   //
   eve = u3m_love(u3ke_cue(u3ke_jam(eve)));
 
+  //  install an ivory pill to support stack traces
+  //
+  //    XX support -J
+  //
+  {
+    c3_d  len_d = u3_Ivory_pill_len;
+    c3_y* byt_y = u3_Ivory_pill;
+    u3_cue_xeno* sil_u = u3s_cue_xeno_init_with(ur_fib27, ur_fib28);
+    u3_weak pil;
+
+    if ( u3_none == (pil = u3s_cue_xeno_with(sil_u, len_d, byt_y)) ) {
+      u3l_log("lite: unable to cue ivory pill");
+      exit(1);
+    }
+
+    u3s_cue_xeno_done(sil_u);
+
+    if ( c3n == u3v_boot_lite(pil)) {
+      u3l_log("lite: boot failed");
+      exit(1);
+    }
+  }
+
   u3l_log("--------------- bootstrap starting ----------------");
 
   u3l_log("boot: 1-%u", u3qb_lent(eve));
@@ -195,10 +220,11 @@ _mars_do_boot(u3_disk* log_u, c3_d eve_d)
 
 /* u3_mars_play(): replay up to [eve_d], snapshot every [sap_d].
 */
-void
+c3_d
 u3_mars_play(u3_mars* mar_u, c3_d eve_d, c3_d sap_d)
 {
   u3_disk* log_u = mar_u->log_u;
+  c3_d     pay_d = 0;
 
   if ( !eve_d ) {
     eve_d = log_u->dun_d;
@@ -207,17 +233,18 @@ u3_mars_play(u3_mars* mar_u, c3_d eve_d, c3_d sap_d)
     u3l_log("mars: already computed %" PRIu64 "", eve_d);
     u3l_log("      state=%" PRIu64 ", log=%" PRIu64 "",
             mar_u->dun_d, log_u->dun_d);
-    return;
+    return pay_d;
   }
   else {
     eve_d = c3_min(eve_d, log_u->dun_d);
   }
 
   if ( mar_u->dun_d == log_u->dun_d ) {
-    u3l_log("mars: nothing to do!");
-    return;
+    return pay_d;
   }
 
+  pay_d = eve_d - mar_u->dun_d;
+
   if ( !mar_u->dun_d ) {
     c3_w lif_w;
 
@@ -351,4 +378,6 @@ u3_mars_play(u3_mars* mar_u, c3_d eve_d, c3_d sap_d)
 
   u3l_log("---------------- playback complete ----------------");
   u3m_save();
+
+  return pay_d;
 }
diff --git a/pkg/vere/mars.h b/pkg/vere/mars.h
index ba97f63614..552f1a9dea 100644
--- a/pkg/vere/mars.h
+++ b/pkg/vere/mars.h
@@ -15,7 +15,7 @@
 
     /* u3_mars_play(): replay up to [eve_d], snapshot every [sap_d].
     */
-      void
+      c3_d
       u3_mars_play(u3_mars* mar_u, c3_d eve_d, c3_d sap_d);
 
 #endif /* ifndef U3_VERE_MARS_H */
diff --git a/pkg/vere/pier.c b/pkg/vere/pier.c
index 1e39d14ef4..907e33c319 100644
--- a/pkg/vere/pier.c
+++ b/pkg/vere/pier.c
@@ -675,8 +675,8 @@ _pier_wyrd_fail(u3_pier* pir_u, u3_ovum* egg_u, u3_noun lud)
 //  XX organizing version constants
 //
 #define VERE_NAME  "vere"
-#define VERE_ZUSE  412
-#define VERE_LULL  323
+#define VERE_ZUSE  411
+#define VERE_LULL  322
 
 /* _pier_wyrd_aver(): check for %wend effect and version downgrade. RETAIN
 */
@@ -783,7 +783,7 @@ _pier_on_lord_wyrd_bail(void* ptr_v, u3_ovum* egg_u, u3_noun lud)
 #endif
 }
 
-/* _pier_wyrd_init(): construct %wyrd.
+/* _pier_wyrd_card(): construct %wyrd.
 */
 static u3_noun
 _pier_wyrd_card(u3_pier* pir_u)
@@ -1402,6 +1402,8 @@ _pier_on_lord_live(void* ptr_v)
       //  XX print bootstrap commit complete
       //  XX s/b boot_complete_cb
       //
+      //  XX this codepath should never be hit due to sync replay
+      u3l_log("pier: warning: async replay");
       _pier_play_init(pir_u, log_u->dun_d);
     }
   }
@@ -1641,6 +1643,8 @@ _pier_init(c3_w wag_w, c3_c* pax_c)
       c3_free(pir_u);
       return 0;
     }
+
+    u3_assert( U3D_VER1 == pir_u->log_u->ver_w );
   }
 
   //  initialize compute
diff --git a/pkg/vere/serf.c b/pkg/vere/serf.c
index 3a59005e00..80a5b1ccf3 100644
--- a/pkg/vere/serf.c
+++ b/pkg/vere/serf.c
@@ -3,6 +3,8 @@
 #include "noun.h"
 
 #include "vere.h"
+#include "ivory.h"
+#include "ur.h"
 
 /*
 |%
@@ -49,6 +51,25 @@ ::    next steps:
 --
 */
 
+/*  serf memory-threshold levels
+*/
+enum {
+  _serf_mas_init = 0,  //  initial
+  _serf_mas_hit1 = 1,  //  past low threshold
+  _serf_mas_hit0 = 2   //  have high threshold
+};
+
+/*  serf post-op flags
+*/
+enum {
+  _serf_fag_none = 0,       //  nothing to do
+  _serf_fag_hit1 = 1 << 0,  //  hit low threshold
+  _serf_fag_hit0 = 1 << 1,  //  hit high threshold
+  _serf_fag_mute = 1 << 2,  //  mutated state
+  _serf_fag_much = 1 << 3,  //  bytecode hack
+  _serf_fag_vega = 1 << 4   //  kernel reset
+};
+
 /* _serf_grab(): garbage collect, checking for profiling. RETAIN.
 */
 static void
@@ -172,28 +193,35 @@ u3_serf_grab(void)
 void
 u3_serf_post(u3_serf* sef_u)
 {
-  if ( c3y == sef_u->rec_o ) {
+  if ( sef_u->fag_w & (_serf_fag_hit1|_serf_fag_much|_serf_fag_vega) ) {
     u3m_reclaim();
-    sef_u->rec_o = c3n;
   }
 
   //  XX this runs on replay too, |mass s/b elsewhere
   //
-  if ( c3y == sef_u->mut_o ) {
+  if ( sef_u->fag_w & _serf_fag_mute ) {
     _serf_grab(sef_u->sac);
     sef_u->sac   = u3_nul;
-    sef_u->mut_o = c3n;
   }
 
-  if ( c3y == sef_u->pac_o ) {
+  if ( sef_u->fag_w & _serf_fag_hit0 ) {
     u3a_print_memory(stderr, "serf: pack: gained", u3m_pack());
     u3l_log("");
-    sef_u->pac_o = c3n;
   }
 
   if ( u3C.wag_w & u3o_toss ) {
     u3m_toss();
   }
+
+  sef_u->fag_w = _serf_fag_none;
+}
+
+/* _serf_curb(): check for memory threshold
+*/
+static inline c3_t
+_serf_curb(c3_w pre_w, c3_w pos_w, c3_w hes_w)
+{
+  return (pre_w > hes_w) && (pos_w <= hes_w);
 }
 
 /* _serf_sure_feck(): event succeeded, send effects.
@@ -201,9 +229,6 @@ u3_serf_post(u3_serf* sef_u)
 static u3_noun
 _serf_sure_feck(u3_serf* sef_u, c3_w pre_w, u3_noun vir)
 {
-  c3_o rec_o = c3n;
-  c3_o pac_o = c3n;
-
   //  intercept |mass, observe |reset
   //
   {
@@ -234,7 +259,7 @@ _serf_sure_feck(u3_serf* sef_u, c3_w pre_w, u3_noun vir)
       //  reclaim memory from persistent caches on |reset
       //
       if ( c3__vega == u3h(fec) ) {
-        rec_o = c3y;
+        sef_u->fag_w |= _serf_fag_vega;
       }
 
       riv = u3t(riv);
@@ -251,39 +276,60 @@ _serf_sure_feck(u3_serf* sef_u, c3_w pre_w, u3_noun vir)
   //    For future flexibility, the urgency of the notification is represented
   //    by a *decreasing* number: 0 is maximally urgent, 1 less so, &c.
   //
-  //    high-priority: 2^22 contiguous words remaining (~8 MB)
+  //    high-priority: 2^25 contiguous words remaining (~128 MB)
   //    low-priority:  2^27 contiguous words remaining (~536 MB)
-  //    XX maybe use 2^23 (~16 MB) and 2^26 (~268 MB?
+  //
+  //    once a threshold is hit, it's not a candidate to be hit again
+  //    until memory usage falls below:
+  //
+  //    high-priority: 2^26 contiguous words remaining (~256 MB)
+  //    low-priority:  2^26 + 2^27 contiguous words remaining (~768 MB)
   //
   //    XX these thresholds should trigger notifications sent to the king
   //    instead of directly triggering these remedial actions.
   //
   {
     u3_noun pri = u3_none;
-    c3_w pos_w = u3a_open(u3R);
-    c3_w low_w = (1 << 27);
-    c3_w hig_w = (1 << 22);
+    c3_w  pos_w = u3a_open(u3R);
 
-    if ( (pre_w > low_w) && !(pos_w > low_w) ) {
-      //  XX set flag(s) in u3V so we don't repeat endlessly?
-      //
-      pac_o = c3y;
-      rec_o = c3y;
-      pri   = 1;
+    //  if contiguous free space shrunk, check thresholds
+    //  (and track state to avoid thrashing)
+    //
+    if ( pos_w < pre_w ) {
+      if (  (_serf_mas_hit0 != sef_u->mas_w)
+         && _serf_curb(pre_w, pos_w, 1 << 25) )
+      {
+        sef_u->mas_w  = _serf_mas_hit0;
+        sef_u->fag_w |= _serf_fag_hit0;
+        pri           = 0;
+      }
+      else if (  (_serf_mas_init == sef_u->mas_w)
+              && _serf_curb(pre_w, pos_w, 1 << 27) )
+      {
+        sef_u->mas_w  = _serf_mas_hit1;
+        sef_u->fag_w |= _serf_fag_hit1;
+        pri         = 1;
+      }
     }
-    else if ( (pre_w > hig_w) && !(pos_w > hig_w) ) {
-      pac_o = c3y;
-      rec_o = c3y;
-      pri   = 0;
+    else if ( _serf_mas_init != sef_u->mas_w ) {
+      if ( ((1 << 26) + (1 << 27)) < pos_w ) {
+        sef_u->mas_w = _serf_mas_init;
+      }
+      else if (  (_serf_mas_hit0 == sef_u->mas_w)
+              && ((1 << 26) < pos_w) )
+      {
+        sef_u->mas_w = _serf_mas_hit1;
+      }
     }
+
     //  reclaim memory from persistent caches periodically
     //
     //    XX this is a hack to work two things
     //    - bytecode caches grow rapidly and can't be simply capped
     //    - we don't make very effective use of our free lists
     //
-    else if ( 0 == (sef_u->dun_d % 1000ULL) ) {
-      rec_o = c3y;
+    if ( !(sef_u->dun_d % 1024ULL) ) {
+      sef_u->fag_w |= _serf_fag_much;
     }
 
     //  notify daemon of memory pressure via "fake" effect
@@ -295,9 +341,6 @@ _serf_sure_feck(u3_serf* sef_u, c3_w pre_w, u3_noun vir)
     }
   }
 
-  sef_u->rec_o = c3o(sef_u->rec_o, rec_o);
-  sef_u->pac_o = c3o(sef_u->pac_o, pac_o);
-
   return vir;
 }
 
@@ -312,7 +355,7 @@ _serf_sure_core(u3_serf* sef_u, u3_noun cor)
   u3A->roc     = cor;
   u3A->eve_d   = sef_u->dun_d;
   sef_u->mug_l = u3r_mug(u3A->roc);
-  sef_u->mut_o = c3y;
+  sef_u->fag_w |= _serf_fag_mute;
 }
 
 /* _serf_sure(): event succeeded, save state and process effects.
@@ -538,11 +581,28 @@ _serf_play_life(u3_serf* sef_u, u3_noun eve)
     u3z(len);
   }
 
-  //  ensure zero-initialized kernel
+  //  install an ivory pill to support stack traces
   //
-  //    XX assert?
+  //    XX support -J
   //
-  u3A->roc = 0;
+  {
+    c3_d  len_d = u3_Ivory_pill_len;
+    c3_y* byt_y = u3_Ivory_pill;
+    u3_cue_xeno* sil_u = u3s_cue_xeno_init_with(ur_fib27, ur_fib28);
+    u3_weak pil;
+
+    if ( u3_none == (pil = u3s_cue_xeno_with(sil_u, len_d, byt_y)) ) {
+      u3l_log("lite: unable to cue ivory pill");
+      exit(1);
+    }
+
+    u3s_cue_xeno_done(sil_u);
+
+    if ( c3n == u3v_boot_lite(pil)) {
+      u3l_log("lite: boot failed");
+      exit(1);
+    }
+  }
 
   gon = u3m_soft(0, u3v_life, eve);
 
@@ -997,9 +1057,7 @@ u3_serf_init(u3_serf* sef_u)
   //   }
   // }
 
-  sef_u->pac_o = c3n;
-  sef_u->rec_o = c3n;
-  sef_u->mut_o = c3n;
+  sef_u->fag_w = _serf_fag_none;
   sef_u->sac   = u3_nul;
 
   return rip;
diff --git a/pkg/vere/serf.h b/pkg/vere/serf.h
index 5808f362e7..7cd2ca47d0 100644
--- a/pkg/vere/serf.h
+++ b/pkg/vere/serf.h
@@ -11,9 +11,8 @@
         c3_d    sen_d;             //  last event requested
         c3_d    dun_d;             //  last event processed
         c3_l    mug_l;             //  hash of state
-        c3_o    pac_o;             //  pack kernel
-        c3_o    rec_o;             //  reclaim cache
-        c3_o    mut_o;             //  mutated kerne
+        c3_w    mas_w;             //  memory threshold state
+        c3_w    fag_w;             //  post-op flags
         u3_noun sac;               //  space measurementl
         void  (*xit_f)(void);      //  exit callback
       } u3_serf;
diff --git a/pkg/vere/vere.h b/pkg/vere/vere.h
index cef16810b6..9527246e19 100644
--- a/pkg/vere/vere.h
+++ b/pkg/vere/vere.h
@@ -8,6 +8,7 @@
 #include "noun.h"
 #include "serf.h"
 #include "uv.h"
+#include <types.h>
 
   /** Quasi-tunable parameters.
   **/
@@ -130,6 +131,7 @@
         c3_c*    pax_c;                     //  path of directory
         uv_file  fil_u;                     //  file, opened read-only to fsync
         u3_dent* all_u;                     //  file list
+        u3_dent* dil_u;                     //  directory list
       } u3_dire;
 
     /* u3_save: checkpoint control.
@@ -263,7 +265,7 @@
         c3_o    abo;                        //  -a, abort aggressively
         c3_c*   pil_c;                      //  -B, bootstrap from
         c3_c*   bin_c;                      //  -b, http server bind ip
-        c3_w    hap_w;                      //  -C, cap memo cache
+        c3_w    hap_w;                      //  -C, cap transient memo cache
         c3_o    dry;                        //  -D, dry compute, no checkpoint
         c3_o    dem;                        //  -d, daemon
         c3_c*   eth_c;                      //  -e, ethereum node url
@@ -281,6 +283,7 @@
         c3_o    lit;                        //  -l, lite mode
         c3_y    lom_y;                      //      loom bex
         c3_y    lut_y;                      //      urth-loom bex
+        c3_w    per_w;                      //  -M, cap persistent memo cache
         c3_c*   til_c;                      //  -n, play till eve_d
         c3_o    pro;                        //  -P, profile
         c3_s    per_s;                      //      http port
@@ -313,6 +316,7 @@
       typedef struct _u3_host {
         c3_w       kno_w;                   //  current executing stage
         c3_c*      dir_c;                   //  pier path (no trailing /)
+        c3_d       eve_d;                   //  initial current snapshot
         c3_c*      dem_c;                   //  daemon executable path
         c3_c*      wrk_c;                   //  worker executable path
         c3_d       now_d;                   //  event tick
@@ -538,9 +542,11 @@
           u3_dire*         urb_u;               //  urbit system data
           u3_dire*         com_u;               //  log directory
           c3_o             liv_o;               //  live
-          void*            mdb_u;               //  lmdb environment.
+          c3_w             ver_w;               //  pier version
+          void*            mdb_u;               //  lmdb env of current epoch
           c3_d             sen_d;               //  commit requested
           c3_d             dun_d;               //  committed
+          c3_d             epo_d;               //  current epoch number
           u3_disk_cb        cb_u;               //  callbacks
           u3_read*         red_u;               //  read requests
           union {                               //  write thread/request
@@ -1002,6 +1008,31 @@
         void
         u3_disk_plan(u3_disk* log_u, u3_fact* tac_u);
 
+      /* u3_disk_epoc_init(): create new epoch.
+       */
+        c3_o
+        u3_disk_epoc_init(u3_disk* log_u, c3_d epo_d);
+
+      /* u3_disk_epoc_kill(): delete an epoch.
+       */
+        c3_o
+        u3_disk_epoc_kill(u3_disk* log_u, c3_d epo_d);
+
+      /* u3_disk_epoc_last(): get latest epoch number.
+       */
+        c3_o
+        u3_disk_epoc_last(u3_disk* log_u, c3_d* lat_d);
+
+      /* u3_disk_epoc_list: get descending epoch numbers, "mcut" pattern.
+      */
+        c3_z
+        u3_disk_epoc_list(u3_disk* log_u, c3_d* sot_d);
+
+      /* u3_disk_kindly(): do the needful.
+      */
+        void
+        u3_disk_kindly(u3_disk* log_u, c3_d eve_d);
+
       /* u3_disk_read_list(): synchronously read a cons list of events.
       */
         u3_weak
diff --git a/pkg/vere/ward.c b/pkg/vere/ward.c
index 4c90be7179..9d6c8cbed3 100644
--- a/pkg/vere/ward.c
+++ b/pkg/vere/ward.c
@@ -39,6 +39,7 @@ u3_dire_init(const c3_c* pax_c)
 {
   u3_dire *dir_u = c3_malloc(sizeof *dir_u);
   dir_u->all_u = 0;
+  dir_u->dil_u = 0;
   dir_u->pax_c = c3_malloc(1 + strlen(pax_c));
   strcpy(dir_u->pax_c, pax_c);
 
@@ -61,6 +62,17 @@ u3_dire_free(u3_dire *dir_u)
     }
   }
 
+  {
+    u3_dent *det_u = dir_u->dil_u;
+    u3_dent *nex_u;
+
+    while ( det_u ) {
+      nex_u = det_u->nex_u;
+      u3_dent_free(det_u);
+      det_u = nex_u;
+    }
+  }
+
   c3_free(dir_u->pax_c);
   c3_free(dir_u);
 }