diff --git a/lib/blob.asm b/lib/blob.asm
index a9187b0e..37680b35 100644
--- a/lib/blob.asm
+++ b/lib/blob.asm
@@ -298,454 +298,6 @@ k_pair_source2:             ; --
     nth -1                  ; base'',len',cust tail
     ref std.send_msg
 
-;
-; input stream-requestor interface to a blob
-;   cust,blob -> stream
-;
-
-reader_factory:             ; _ <- cust,blob
-    msg 0                   ; cust,blob
-    push k_reader_init      ; cust,blob k_reader_init
-    actor create            ; k=k_reader_init.cust,blob
-    msg -1                  ; k blob
-    ref std.send_msg
-k_reader_init:              ; cust,blob <- size
-    state -1                ; blob
-    msg 0                   ; blob size
-    push 0                  ; blob size ofs=0
-    pair 2                  ; ofs,size,blob
-    push reader             ; ofs,size,blob reader
-    actor become            ; --
-    actor self              ; SELF
-    state 1                 ; SELF cust
-    ref std.send_msg
-
-reader:                     ; ofs,size,blob <- can,cb,req | data,cb | (len,blob'),k
-    msg 0                   ; msg
-    typeq #pair_t           ; is_pair(msg)
-    if_not std.abort        ; --
-    msg 1                   ; (len,blob)
-    typeq #pair_t           ; is_pair((len,blob))
-    if reader_grow          ; --
-    msg 1                   ; data
-    typeq #fixnum_t         ; is_fix(data)
-    if reader_ok            ; --
-    msg 2                   ; cb
-    typeq #actor_t          ; is_cap(cb)
-    if_not std.abort        ; --
-    msg -2                  ; req
-    eq #?                   ; req==#?
-    if reader_read          ; --
-reader_fail:                ; --
-    push #?                 ; #?
-    push #f                 ; #? #f
-    pair 1                  ; #f,#?
-    msg 2                   ; #f,#? cb
-    ref std.send_msg
-reader_read:                ; --
-    state 1                 ; ofs
-    state 2                 ; ofs size
-    cmp lt                  ; ofs<size
-    if_not reader_end       ; --
-    state 1                 ; ofs
-    actor self              ; ofs SELF
-    msg 2                   ; ofs SELF cb
-    pair 1                  ; ofs cb,SELF
-    push k_blob_r           ; ofs cb,SELF k_blob_r
-    actor create            ; ofs cust=k_blob_r.cb,SELF
-    pair 1                  ; cust,ofs
-    state -2                ; cust,ofs blob
-    ref std.send_msg
-reader_end:                 ; --
-    push #nil               ; #nil
-    push #t                 ; #nil #t
-    pair 1                  ; #t,#nil
-    msg 2                   ; #t,#nil cb
-    ref std.send_msg
-reader_ok:                  ; --
-    state 0                 ; ofs,size,blob
-    part 1                  ; size,blob ofs
-    push 1                  ; size,blob ofs 1
-    alu add                 ; size,blob ofs+1
-    pair 1                  ; state'=ofs+1,size,blob
-    push reader             ; state' reader
-    actor become            ; --
-    msg 1                   ; data
-    push #t                 ; data #t
-    pair 1                  ; #t,data
-    msg -1                  ; #t,data cb
-    ref std.send_msg
-reader_grow:                ; --
-;    msg 0                   ; (len,blob'),k
-    state 0                 ; ofs,size,blob
-    part 2                  ; blob size ofs
-    msg 1                   ; blob size ofs (len,blob')
-    part 1                  ; blob size ofs blob' len
-    roll 2                  ; blob size ofs len blob'
-    roll 5                  ; size ofs len blob' blob
-    pair 1                  ; size ofs len blob,blob'
-    push pair               ; size ofs len blob,blob' pair
-    actor create            ; size ofs len blob''=pair.blob,blob'
-    roll 2                  ; size ofs blob'' len
-    roll 4                  ; ofs blob'' len size
-    alu add                 ; ofs blob'' size'=len+size
-    roll 3                  ; blob'' size'' ofs
-    pair 2                  ; state'=ofs,size',blob''
-    push reader             ; state' reader
-    actor become            ; --
-    actor self              ; SELF
-    msg -1                  ; SELF k
-    ref std.send_msg
-
-k_blob_r:                   ; cb,stream <- byte | #?
-    msg 0                   ; msg
-    eq #?                   ; msg==#?
-    if k_cb_fail k_cb_ok    ; --
-k_blob_w:                   ; cb,stream <- #t | #f
-    msg 0                   ; msg
-    if k_cb_ok k_cb_fail    ; --
-k_cb_ok:                    ; --
-    state 1                 ; cb
-    msg 0                   ; cb data
-    pair 1                  ; data,cb
-    state -1                ; data,cb stream
-    ref std.send_msg
-k_cb_fail:                  ; --
-    msg 0                   ; msg
-    push #f                 ; msg #f
-    pair 1                  ; #f,msg
-    state 1                 ; #f,msg cb
-    ref std.send_msg
-
-;
-; output stream-requestor interface to an auto-allocated blob
-;   cust,blk_size -> stream
-;
-
-writer_factory:             ; blob_dev <- cust,blk_size
-    msg -1                  ; len=blk_size
-    state 0                 ; len blob_dev
-    msg 0                   ; len blob_dev cust,blk_size
-    part 1                  ; len blob_dev blk_size cust
-    pair 2                  ; len cust,blk_size,blob_dev
-    push k_writer_init      ; len cust,blk_size,blob_dev k_writer_init
-    actor create            ; len k=k_writer_init.cust,blk_size,blob_dev
-    pair 1                  ; k,len
-    state 0                 ; k,len blob_dev
-    ref std.send_msg
-
-k_writer_init:              ; cust,blk_size,blob_dev <- blob
-    msg 0                   ; blob
-    typeq #actor_t          ; is_cap(blob)
-    if_not writer_init_fail ; --
-    state -2                ; blob_dev
-    msg 0                   ; blob_dev blob
-    push wr_blob            ; blob_dev blob wr_blob
-    actor create            ; blob_dev first=wr_blob.blob
-    state 2                 ; blob_dev first size=blk_size
-    pick 2                  ; blob_dev first size first
-    push 0                  ; blob_dev first size first ofs=0
-    pair 4                  ; ofs,first,size,first,blob_dev
-    push writer             ; ofs,first,size,first,blob_dev writer
-    actor become            ; --
-    actor self              ; SELF
-    state 1                 ; SELF cust
-    ref std.send_msg
-writer_init_fail:           ; --
-    push #?                 ; #?
-    state 1                 ; #? cust
-    ref std.send_msg
-
-wr_blob:                    ; blob <- cust,len | cust,next | cust,ofs,data
-    msg 1                   ; cust
-    typeq #actor_t          ; is_cap(cust)
-    if_not std.abort        ; --
-    msg -1                  ; req
-    typeq #fixnum_t         ; is_fix(req)
-    if wr_slice             ; --
-    msg -1                  ; req
-    typeq #actor_t          ; is_cap(req)
-    if wr_pair              ; --
-    msg -1                  ; req
-    typeq #pair_t           ; is_pair(req)
-    if_not std.abort        ; --
-wr_write:                   ; write into blob
-    msg 0                   ; cust,ofs,data
-    state 0                 ; cust,ofs,data blob
-    ref std.send_msg
-wr_slice:                   ; convert to blob.slice
-;    msg 0                   ; cust,len
-    state 0                 ; blob
-    msg -1                  ; blob len
-    push 0                  ; blob len base=0
-    pair 2                  ; base,len,blob
-    push slice              ; base,len,blob slice
-    actor become            ; --
-    actor self              ; SELF
-    msg 1                   ; SELF cust
-    ref std.send_msg
-wr_pair:                    ; convert to blob.pair
-;    msg 0                   ; cust,next
-    msg -1                  ; tail=next
-    state 0                 ; tail head=blob
-    pair 1                  ; head,tail
-    push pair               ; head,tail pair
-    actor become            ; --
-    msg 0                   ; cust,next
-    part 1                  ; next cust
-    ref std.send_msg
-
-writer:                     ; ofs,blob,size,blobs,blob_dev <- can,cb,req | ok,cb | (can,cb,req),blob''
-    msg 0                   ; msg
-    typeq #pair_t           ; is_pair(msg)
-    if_not std.abort        ; --
-    msg 1                   ; (can,cb,req)
-    typeq #pair_t           ; is_pair((can,cb,req))
-    if writer_grown         ; --
-    msg -1                  ; cb
-    typeq #actor_t          ; is_cap(cb)
-    if writer_done          ; --
-    msg -2                  ; req
-    eq #?                   ; req==#?
-    if writer_read          ; --
-    msg -2                  ; req
-    typeq #fixnum_t         ; is_fix(req)
-    if writer_write         ; --
-    ref std.abort
-
-writer_read:                ; --
-    state 1                 ; len=ofs
-    state 4                 ; len blobs
-    msg 2                   ; len blobs cb
-    pair 1                  ; len cb,blobs
-    push writer_stone       ; len cb,blobs writer_stone
-    actor create            ; len cust=writer_stone.cb,blobs
-    pair 1                  ; cust,len
-    state 2                 ; cust,len blob
-    ref std.send_msg
-writer_stone:               ; cb,blobs <- slice
-    state -1                ; blobs
-    push #t                 ; blobs #t
-    pair 1                  ; #t,blobs
-    state 1                 ; #t,blobs cb
-    ref std.send_msg
-
-writer_write:               ; --
-    state 1                 ; ofs
-    state 3                 ; ofs size
-    cmp lt                  ; ofs<size
-    if_not writer_grow      ; --
-    msg -2                  ; data
-    state 1                 ; data ofs
-    actor self              ; data ofs SELF
-    msg 2                   ; data ofs SELF cb
-    pair 1                  ; data ofs cb,SELF
-    push k_blob_w           ; data ofs cb,SELF k_blob_w
-    actor create            ; data ofs cust=k_blob_w.wr,cb
-    pair 2                  ; cust,ofs,data
-    state 2                 ; cust,ofs,data blob
-    ref std.send_msg
-
-writer_done:                ; --
-    msg 1                   ; ok
-    if writer_ok            ; --
-    push #?                 ; #?
-    push #f                 ; #? #f
-    pair 1                  ; #f,#?
-    msg -1                  ; #f,#? cb
-    ref std.send_msg
-writer_ok:                  ; --
-    state 0                 ; ofs,blob,size,blobs,blob_dev
-    part 1                  ; blob,size,blobs,blob_dev ofs
-    push 1                  ; blob,size,blobs,blob_dev ofs 1
-    alu add                 ; blob,size,blobs,blob_dev ofs+1
-    pair 1                  ; ofs+1,blob,size,blobs,blob_dev
-    push writer             ; ofs+1,blob,size,blobs,blob_dev writer
-    actor become            ; --
-    push #?                 ; #?
-    push #t                 ; #? #t
-    pair 1                  ; #t,#?
-    msg -1                  ; #t,#? cb
-    ref std.send_msg
-
-writer_grow:                ; --
-    state 3                 ; len=size
-    state 0                 ; len state=ofs,blob,size,blobs,blob_dev
-    msg 0                   ; len state msg=can,cb,req
-    actor self              ; len state msg wr=SELF
-    pair 2                  ; len wr,msg,state
-    push k_writer_grow      ; len wr,msg,state k_writer_grow
-    actor create            ; len k=k_writer_grow.wr,msg,state
-    pair 1                  ; k,len
-    state -4                ; k,len blob_dev
-    ref std.send_msg
-k_writer_grow:              ; wr,(can,cb,req),ofs,blob,size,blobs,blob_dev <- blob'
-    msg 0                   ; blob'
-    push wr_blob            ; blob' wr_blob
-    actor create            ; next=wr_blob.blob'
-    state 0                 ; next state
-    push k_writer_grow2     ; next state k_writer_grow2
-    actor create            ; next k=k_writer_grow2.state
-    pair 1                  ; k,next
-    state 4                 ; k,next blob
-    ref std.send_msg
-k_writer_grow2:             ; wr,(can,cb,req),ofs,blob,size,blobs,blob_dev <- blob''
-    state 0                 ; wr,(can,cb,req),ofs,blob,size,blobs,blob_dev
-    part 2                  ; ofs,blob,size,blobs,blob_dev (can,cb,req) wr
-    msg 0                   ; ... (can,cb,req) wr blob''
-    roll 3                  ; ... wr blob'' (can,cb,req)
-    pair 1                  ; ... wr (can,cb,req),blob''
-    roll 2                  ; ... (can,cb,req),blob'' wr
-    ref std.send_msg
-
-writer_grown:               ; --
-    state -2                ; size,blobs,blob_dev
-    msg -1                  ; size,blobs,blob_dev blob''
-    push 0                  ; size,blobs,blob_dev blob'' ofs=0
-    pair 2                  ; ofs,blob'',size,blobs,blob_dev
-    push writer             ; ofs,blob'',size,blobs,blob_dev writer
-    actor become            ; --
-    msg 1                   ; (can,cb,req)
-    actor self              ; (can,cb,req) SELF
-    ref std.send_msg
-
-;
-; copy stream `in` to stream `out`
-; sending the final `result` to `cb`
-;
-stream_copy:                ; cb,out,in <- result
-    msg 1                   ; ok
-    if_not stream_end       ; --
-
-    msg -1                  ; value
-    eq #nil                 ; value==#nil
-    if stream_end           ; --
-
-    msg -1                  ; value
-    typeq #fixnum_t         ; is_fix(value)
-    if stream_write         ; --
-
-stream_read:                ; --
-    push #?                 ; #?
-    actor self              ; #? callback=SELF
-    push #?                 ; #? callback to_cancel=#?
-    pair 2                  ; req=to_cancel,callback,#?
-    state -2                ; req in
-    ref std.send_msg
-
-stream_write:               ; --
-    msg -1                  ; char
-    actor self              ; char callback=SELF
-    push #?                 ; char callback to_cancel=#?
-    pair 2                  ; req=to_cancel,callback,char
-    state 2                 ; req out
-    ref std.send_msg
-
-stream_end:                 ; --
-    msg 0                   ; result
-    state 1                 ; result cb
-    ref std.send_msg
-
-;
-; blob interface to a blob-stream
-;
-
-blobstr:                    ; blob,str,cb <- ok,blob' | cust | cust,ofs | cust,ofs,data | base',len',cust
-    msg 1                   ; ok
-    eq #t                   ; ok==#t
-    if blobstr_ok           ; --
-    msg 1                   ; ok
-    eq #f                   ; ok==#f
-    if blobstr_done         ; --
-    msg 0                   ; msg
-    state 1                 ; msg blob
-    ref std.send_msg
-blobstr_ok:                 ; --
-    msg -1                  ; blob'
-    typeq #actor_t          ; is_cap(blob')
-    if_not blobstr_done     ; --
-    state 0                 ; blob,str,cb
-    part 1                  ; str,cb blob
-    dup 1                   ; str,cb blob blob
-    typeq #actor_t          ; str,cb blob is_cap(blob)
-    if blobstr_pair         ; str,cb blob
-    drop 1                  ; str,cb
-    msg -1                  ; str,cb blob'
-    ref blobstr_update
-blobstr_pair:               ; str,cb blob
-    msg -1                  ; str,cb blob blob'
-    roll 2                  ; str,cb blob' blob
-    pair 1                  ; str,cb blob,blob'
-    push pair               ; str,cb blob,blob' pair
-    actor create            ; str,cb blob''=pair.blob,blob'
-blobstr_update:             ; str,cb blob''
-    pair 1                  ; blob'',str,cb
-    push blobstr            ; blob'',str,cb blobstr
-    actor become            ; --
-    push #?                 ; req=#?
-    actor self              ; req cb=SELF
-    push #?                 ; req cb can=#?
-    pair 2                  ; can,cb,req
-    state 2                 ; can,cb,req str
-    ref std.send_msg
-blobstr_done:               ; --
-    state -2                ; cb
-    typeq #actor_t          ; is_cap(cb)
-    if_not std.commit       ; --
-    msg 0                   ; ok,value
-    state -2                ; ok,value cb
-    ref std.send_msg
-
-;
-; read-stream of source-blobs
-;
-
-strsource:                  ; offset,size,blob <- can,cb,#? | (base,len,blob'),cb
-    msg 1                   ; (base,len,blob')
-    typeq #pair_t           ; is_pair((base,len,blob'))
-    if strsource_result     ; --
-    state 0                 ; offset,size,blob
-    part 2                  ; blob size offset
-    actor self              ; blob size offset SELF
-    msg 2                   ; blob size offset SELF cb
-    pair 1                  ; blob size offset cb,SELF
-    push k_strsource        ; blob size offset cb,SELF k_strsource
-    actor create            ; blob size offset cust=k_strsource.cb,SELF
-    roll -3                 ; blob cust len=size base=offset
-    pair 2                  ; blob base,len,cust
-    roll 2                  ; base,len,cust blob
-    ref std.send_msg
-strsource_result:           ; --
-    msg 1                   ; base,len,blob'
-    nth 2                   ; len
-    eq 0                    ; len==0
-    if strsource_done       ; --
-    state 0                 ; offset,size,blob
-    part 1                  ; size,blob offset
-    msg 1                   ; size,blob offset base,len,blob'
-    nth 2                   ; size,blob offset len
-    alu add                 ; size,blob offset+len
-    pair 1                  ; offset+len,size,blob
-    push strsource          ; offset+len,size,blob strsource
-    actor become            ; --
-    msg 1                   ; base,len,blob'
-    push slice              ; base,len,blob' slice
-    actor create            ; blob''=slice.base,len,blob'
-strsource_send:             ; blob''
-    push #t                 ; blob'' #t
-    pair 1                  ; #t,blob''
-    msg -1                  ; #t,blob'' cb
-    ref std.send_msg
-strsource_done:             ; --
-    push #nil               ; blob''=#nil
-    ref strsource_send
-
-k_strsource:                ; cb,str <- base,len,blob'
-    state 1                 ; cb
-    msg 0                   ; cb base,len,blob'
-    pair 1                  ; (base,len,blob'),cb
-    state -1                ; (base,len,blob'),cb str
-    ref std.send_msg
 
 ;
 ; usage demonstration
@@ -807,223 +359,6 @@ crlf:
     pair_t '\n'
     ref #nil                ; size=19
 
-demo_blobstr:               ; {caps} <- blob
-;blobstr:                    ; blob,str,cb <- ok,blob' | cust | cust,ofs | cust,ofs,data | base',len',cust
-    state 0                 ; {caps}
-    msg 0                   ; {caps} head=blob
-    pair 1                  ; head,{caps}
-    push k_demo_blobstr     ; head,{caps} demo=k_demo_blobstr
-    actor become            ; --
-;    msg 0                   ; tail=blob
-;    actor self              ; tail SELF
-;    ref std.send_msg
-    push http_req_hdrs      ; list=http_req_hdrs
-    actor self              ; list cust=SELF
-    pair 1                  ; cust,list
-    state 0                 ; cust,list {caps}
-    push dev.blob_key       ; cust,list {caps} blob_key
-    dict get                ; cust,list blob_dev
-    push init               ; cust,list blob_dev init
-    actor create            ; cust,list init.blob_dev
-    ref std.send_msg
-k_demo_blobstr:             ; head,{caps} <- tail
-    state -1                ; {caps}
-    push k_demo_blobstr1    ; {caps} demo=k_demo_blobstr1
-    actor become            ; --
-    msg 0                   ; tail
-    state 1                 ; tail head
-    pair 1                  ; head,tail
-    push pair               ; head,tail pair
-    actor create            ; blob=pair.head,tail
-    actor self              ; blob SELF
-    ref std.send_msg
-k_demo_blobstr1:            ; {caps} <- blob
-    actor self              ; cb=SELF
-    msg 0                   ; cb blob
-;    push 1024               ; cb blob size=1024
-    push 10                 ; cb blob size=10
-    push 0                  ; cb blob size offset=0
-    pair 2                  ; cb offset,size,blob
-    push strsource          ; cb offset,size,blob strsource
-    actor create            ; cb str=strsource.offset,size,blob
-
-    pick -2                 ; str cb str
-    push #nil               ; str cb str blob=#nil
-    pair 2                  ; str blob,str,cb
-    push blobstr            ; str blob,str,cb blobstr
-    actor create            ; str blob'=blobstr.blob,str,cb
-
-    state 0                 ; str blob' {caps}
-    pick 2                  ; str blob' {caps} blob'
-    pair 1                  ; str blob' blob',{caps}
-    push k_demo_blobstr2    ; str blob' blob',{caps} k_demo_blobstr2
-    actor become            ; str blob'
-
-    push #?                 ; str blob' req=#?
-    roll 2                  ; str req cb=blob'
-    push #?                 ; str req cb can=#?
-    pair 2                  ; str can,cb,req
-    roll 2                  ; can,cb,req str
-    ref std.send_msg
-k_demo_blobstr2:            ; blob',{caps} <- ok,value
-    state -1                ; {caps}
-    push k_demo_blobstr9    ; {caps} k_demo_blobstr9
-    actor become            ; --
-    state 1                 ; blob'
-    actor self              ; blob' SELF
-    ref std.send_msg
-k_demo_blobstr9:            ; {caps} <- blob
-    msg 0                   ; blob
-    state 0                 ; blob {caps}
-;    push demo_debug         ; blob {caps} demo=demo_debug
-;    push demo_size          ; blob {caps} demo=demo_size
-    push demo_print         ; blob {caps} demo=demo_print
-;    push demo_source        ; blob {caps} demo=demo_source
-    actor create            ; blob demo.{caps}
-    ref std.send_msg
-
-demo_strsource:             ; {caps} <- blob
-    state 0                 ; {caps}
-    msg 0                   ; {caps} head=blob
-    pair 1                  ; head,{caps}
-    push k_demo_strsource   ; head,{caps} demo=k_demo_strsource
-    actor become            ; --
-;    msg 0                   ; tail=blob
-;    actor self              ; tail SELF
-;    ref std.send_msg
-    push http_req_hdrs      ; list=http_req_hdrs
-    actor self              ; list cust=SELF
-    pair 1                  ; cust,list
-    state 0                 ; cust,list {caps}
-    push dev.blob_key       ; cust,list {caps} blob_key
-    dict get                ; cust,list blob_dev
-    push init               ; cust,list blob_dev init
-    actor create            ; cust,list init.blob_dev
-    ref std.send_msg
-k_demo_strsource:           ; head,{caps} <- tail
-    state -1                ; {caps}
-    push k_demo_strsource1  ; {caps} demo=k_demo_strsource1
-    actor become            ; --
-    msg 0                   ; tail
-    state 1                 ; tail head
-    pair 1                  ; head,tail
-    push pair               ; head,tail pair
-    actor create            ; blob=pair.head,tail
-    actor self              ; blob SELF
-    ref std.send_msg
-k_demo_strsource1:          ; {caps} <- blob
-    msg 0                   ; blob
-;    push 1024               ; blob size=1024
-    push 10                 ; blob size=10
-    push 0                  ; blob size offset=0
-    pair 2                  ; offset,size,blob
-    push strsource          ; offset,size,blob strsource
-    actor create            ; str=strsource.offset,size,blob
-    push #?                 ; str req=#?
-    state 0                 ; str req {caps}
-    pick 3                  ; str req {caps} str
-    pair 1                  ; str req str,{caps}
-    push k_demo_strsource2  ; str req str,{caps} k_demo_strsource2
-    actor create            ; str req cb=k_demo_strsource2.str,{caps}
-    push #?                 ; str req cb can=#?
-    pair 2                  ; str can,cb,req
-    roll 2                  ; can,cb,req str
-    ref std.send_msg
-k_demo_strsource2:          ; str,{caps} <- ok,blob'
-    msg 1                   ; ok
-    eq #t                   ; ok==#t
-    if_not k_demo_strsource3; --
-    msg -1                  ; blob'
-    typeq #actor_t          ; is_cap(blob')
-    if_not k_demo_strsource3; --
-
-    push #?                 ; req=#?
-    actor self              ; req cb=SELF
-    push #?                 ; req cb can=#?
-    pair 2                  ; can,cb,req
-    state 1                 ; can,cb,req str
-    actor send              ; --
-
-    msg -1                  ; blob'
-    state -1                ; blob' {caps}
-;    push demo_debug         ; blob' {caps} demo=demo_debug
-;    push demo_size          ; blob' {caps} demo=demo_size
-;    push demo_print         ; blob' {caps} demo=demo_print -- CAUTION: scrambled output
-    push demo_source        ; blob' {caps} demo=demo_source
-    actor create            ; blob' demo.{caps}
-    ref std.send_msg
-k_demo_strsource3:          ; --
-    msg 0                   ; ok,blob'
-    state -1                ; ok,blob' {caps}
-    push dev.debug_key      ; ok,blob' {caps} debug_key
-    dict get                ; ok,blob' debug_dev
-    ref std.send_msg
-
-demo_writer:                ; {caps} <- blob
-    msg 0                   ; blob
-    state 0                 ; blob {caps}
-    push k_demo_writer      ; blob {caps} k_demo_writer
-    actor create            ; blob cust=k_demo_print.{caps}
-    pair 1                  ; cust,blob
-    push #?                 ; cust,blob #?
-    push reader_factory     ; cust,blob #? reader_factory
-    actor create            ; cust,blob reader_factory._
-    ref std.send_msg
-k_demo_writer:              ; {caps} <- in
-    state 0                 ; {caps}
-    msg 0                   ; {caps} in
-    pair 1                  ; in,{caps}
-    push k_demo_writer2     ; in,{caps} k_demo_writer2
-    actor become            ; --
-
-    push 10                 ; blk_size=10
-;    push 7                  ; blk_size=7
-    actor self              ; blk_size cust=SELF
-    pair 1                  ; cust,blk_size
-
-    state 0                 ; cust,blk_size {caps}
-    push dev.blob_key       ; cust,blk_size {caps} blob_key
-    dict get                ; cust,blk_size blob_dev
-    push writer_factory     ; cust,blk_size blob_dev writer_factory
-    actor create            ; cust,blk_size writer_factory.blob_dev
-    ref std.send_msg
-k_demo_writer2:             ; in,{caps} <- out
-    state -1                ; {caps}
-    msg 0                   ; {caps} out
-    pair 1                  ; out,{caps}
-    push k_demo_writer3     ; out,{caps} k_demo_writer3
-    actor become            ; --
-
-    state 1                 ; in
-    msg 0                   ; in out
-    actor self              ; in out cb=SELF
-    pair 2                  ; cb,out,in
-    push stream_copy        ; cb,out,in stream_copy
-    actor create            ; tgt=stream_copy.cb,out,in
-    ref tgt_start
-k_demo_writer3:             ; out,{caps} <- result
-    state -1                ; {caps}
-    push k_demo_writer4     ; {caps} k_demo_writer4
-    actor become            ; --
-
-    push #?                 ; #?
-    actor self              ; #? cb=SELF
-    push #?                 ; #? cb can=#?
-    pair 2                  ; can,cb,#?
-    state 1                 ; can,cb,#? out
-    ref std.send_msg
-k_demo_writer4:           ; {caps} <- result
-    state 0                 ; {caps}
-;    push demo_debug         ; {caps} demo=demo_debug
-;    push demo_size          ; {caps} demo=demo_size
-    push demo_print         ; {caps} demo=demo_print
-;    push demo_source        ; {caps} demo=demo_source
-    actor become            ; --
-
-    msg -1                  ; blob
-    actor self              ; blob SELF
-    ref std.send_msg
-
 demo_composite:             ; {caps} <- blob
     state 0                 ; {caps}
     push k_demo_composite   ; {caps} demo=k_demo_composite
@@ -1052,7 +387,6 @@ demo_composite:             ; {caps} <- blob
 k_demo_composite:           ; {caps} <- blob
     state 0                 ; {caps}
 ;    push demo_size          ; {caps} demo=demo_size
-;    push demo_print         ; {caps} demo=demo_print
     push demo_source        ; {caps} demo=demo_source
     actor become            ; --
     msg 0                   ; blob
@@ -1115,8 +449,7 @@ k_demo_pair2:               ; blob,{caps} <- wr_ok
 k_demo_pair3:               ; blob,{caps} <- wr_ok
     state -1                ; {caps}
 ;    push demo_size          ; {caps} demo=demo_size
-    push demo_print         ; {caps} demo=demo_print
-;    push demo_source        ; {caps} demo=demo_source
+    push demo_source        ; {caps} demo=demo_source
     actor become            ; --
     state 1                 ; blob
     actor self              ; blob SELF
@@ -1125,8 +458,7 @@ k_demo_pair3:               ; blob,{caps} <- wr_ok
 demo_slice:                 ; {caps} <- blob
     state 0                 ; {caps}
 ;    push demo_size          ; {caps} demo=demo_size
-    push demo_print         ; {caps} demo=demo_print
-;    push demo_source        ; {caps} demo=demo_source
+    push demo_source        ; {caps} demo=demo_source
     actor become            ; --
     msg 0                   ; blob
     push 11                 ; blob len=11
@@ -1151,36 +483,7 @@ demo_size:                  ; {caps} <- blob
     msg 0                   ; debug_dev blob
     ref std.send_msg
 
-demo_print:                 ; {caps} <- blob
-    msg 0                   ; blob
-    state 0                 ; blob {caps}
-    push k_demo_print       ; blob {caps} k_demo_print
-    actor create            ; blob cust=k_demo_print.{caps}
-    pair 1                  ; cust,blob
-    push #?                 ; cust,blob #?
-    push reader_factory     ; cust,blob #? reader_factory
-    actor create            ; cust,blob reader_factory._
-    ref std.send_msg
-k_demo_print:               ; {caps} <- in
-    msg 0                   ; in
-    state 0                 ; in {caps}
-    push dev.io_key         ; in {caps} io_key
-    dict get                ; in out=io_dev
-    state 0                 ; in out {caps}
-    push dev.debug_key      ; in out {caps} debug_key
-    dict get                ; in out cb=debug_dev
-    pair 2                  ; cb,out,in
-    push stream_copy        ; cb,out,in stream_copy
-    actor create            ; tgt=stream_copy.cb,out,in
-tgt_start:                  ; tgt
-    push #?                 ; tgt value=#?
-    push #t                 ; tgt #? ok=#t
-    pair 1                  ; tgt result=ok,value
-    roll 2                  ; result tgt
-    ref std.send_msg
-
 demo_source:                ; {caps} <- blob
-    debug
     state 0                 ; {caps}
     push dev.debug_key      ; {caps} debug_key
     dict get                ; cust=debug_dev
@@ -1198,14 +501,10 @@ boot:                       ; _ <- {caps}
     msg 0                   ; list {caps}
 ;    push demo_debug         ; list {caps} demo=demo_debug
 ;    push demo_size          ; list {caps} demo=demo_size
-;    push demo_print         ; list {caps} demo=demo_print
 ;    push demo_source        ; list {caps} demo=demo_source
 ;    push demo_slice         ; list {caps} demo=demo_slice
-;    push demo_pair          ; list {caps} demo=demo_pair
+    push demo_pair          ; list {caps} demo=demo_pair
 ;    push demo_composite     ; list {caps} demo=demo_composite
-;    push demo_writer        ; list {caps} demo=demo_writer
-;    push demo_strsource     ; list {caps} demo=demo_strsource
-    push demo_blobstr       ; list {caps} demo=demo_blobstr
     actor create            ; list cust=demo.{caps}
     pair 1                  ; cust,list
     msg 0                   ; cust,list {caps}
@@ -1219,9 +518,4 @@ boot:                       ; _ <- {caps}
     init
     slice
     pair
-    reader_factory
-    writer_factory
-    stream_copy
-    blobstr
-    strsource
     boot
diff --git a/lib/blob_io.asm b/lib/blob_io.asm
new file mode 100644
index 00000000..94ea288b
--- /dev/null
+++ b/lib/blob_io.asm
@@ -0,0 +1,931 @@
+;
+; Blob (binary large object) I/O streams
+;
+
+.import
+    dev: "https://ufork.org/lib/dev.asm"
+    std: "https://ufork.org/lib/std.asm"
+    blob: "https://ufork.org/lib/blob.asm"
+
+;
+; input stream-requestor interface to a blob
+;   cust,blob -> stream
+;
+
+reader_factory:             ; _ <- cust,blob
+    msg 0                   ; cust,blob
+    push k_reader_init      ; cust,blob k_reader_init
+    actor create            ; k=k_reader_init.cust,blob
+    msg -1                  ; k blob
+    ref std.send_msg
+k_reader_init:              ; cust,blob <- size
+    state -1                ; blob
+    msg 0                   ; blob size
+    push 0                  ; blob size ofs=0
+    pair 2                  ; ofs,size,blob
+    push reader             ; ofs,size,blob reader
+    actor become            ; --
+    actor self              ; SELF
+    state 1                 ; SELF cust
+    ref std.send_msg
+
+reader:                     ; ofs,size,blob <- can,cb,req | data,cb | (len,blob'),k
+    msg 0                   ; msg
+    typeq #pair_t           ; is_pair(msg)
+    if_not std.abort        ; --
+    msg 1                   ; (len,blob)
+    typeq #pair_t           ; is_pair((len,blob))
+    if reader_grow          ; --
+    msg 1                   ; data
+    typeq #fixnum_t         ; is_fix(data)
+    if reader_ok            ; --
+    msg 2                   ; cb
+    typeq #actor_t          ; is_cap(cb)
+    if_not std.abort        ; --
+    msg -2                  ; req
+    eq #?                   ; req==#?
+    if reader_read          ; --
+reader_fail:                ; --
+    push #?                 ; #?
+    push #f                 ; #? #f
+    pair 1                  ; #f,#?
+    msg 2                   ; #f,#? cb
+    ref std.send_msg
+reader_read:                ; --
+    state 1                 ; ofs
+    state 2                 ; ofs size
+    cmp lt                  ; ofs<size
+    if_not reader_end       ; --
+    state 1                 ; ofs
+    actor self              ; ofs SELF
+    msg 2                   ; ofs SELF cb
+    pair 1                  ; ofs cb,SELF
+    push k_blob_r           ; ofs cb,SELF k_blob_r
+    actor create            ; ofs cust=k_blob_r.cb,SELF
+    pair 1                  ; cust,ofs
+    state -2                ; cust,ofs blob
+    ref std.send_msg
+reader_end:                 ; --
+    push #nil               ; #nil
+    push #t                 ; #nil #t
+    pair 1                  ; #t,#nil
+    msg 2                   ; #t,#nil cb
+    ref std.send_msg
+reader_ok:                  ; --
+    state 0                 ; ofs,size,blob
+    part 1                  ; size,blob ofs
+    push 1                  ; size,blob ofs 1
+    alu add                 ; size,blob ofs+1
+    pair 1                  ; state'=ofs+1,size,blob
+    push reader             ; state' reader
+    actor become            ; --
+    msg 1                   ; data
+    push #t                 ; data #t
+    pair 1                  ; #t,data
+    msg -1                  ; #t,data cb
+    ref std.send_msg
+reader_grow:                ; --
+;    msg 0                   ; (len,blob'),k
+    state 0                 ; ofs,size,blob
+    part 2                  ; blob size ofs
+    msg 1                   ; blob size ofs (len,blob')
+    part 1                  ; blob size ofs blob' len
+    roll 2                  ; blob size ofs len blob'
+    roll 5                  ; size ofs len blob' blob
+    pair 1                  ; size ofs len blob,blob'
+    push blob.pair          ; size ofs len blob,blob' pair
+    actor create            ; size ofs len blob''=pair.blob,blob'
+    roll 2                  ; size ofs blob'' len
+    roll 4                  ; ofs blob'' len size
+    alu add                 ; ofs blob'' size'=len+size
+    roll 3                  ; blob'' size'' ofs
+    pair 2                  ; state'=ofs,size',blob''
+    push reader             ; state' reader
+    actor become            ; --
+    actor self              ; SELF
+    msg -1                  ; SELF k
+    ref std.send_msg
+
+k_blob_r:                   ; cb,stream <- byte | #?
+    msg 0                   ; msg
+    eq #?                   ; msg==#?
+    if k_cb_fail k_cb_ok    ; --
+k_blob_w:                   ; cb,stream <- #t | #f
+    msg 0                   ; msg
+    if k_cb_ok k_cb_fail    ; --
+k_cb_ok:                    ; --
+    state 1                 ; cb
+    msg 0                   ; cb data
+    pair 1                  ; data,cb
+    state -1                ; data,cb stream
+    ref std.send_msg
+k_cb_fail:                  ; --
+    msg 0                   ; msg
+    push #f                 ; msg #f
+    pair 1                  ; #f,msg
+    state 1                 ; #f,msg cb
+    ref std.send_msg
+
+;
+; output stream-requestor interface to an auto-allocated blob
+;   cust,blk_size -> stream
+;
+
+writer_factory:             ; blob_dev <- cust,blk_size
+    msg -1                  ; len=blk_size
+    state 0                 ; len blob_dev
+    msg 0                   ; len blob_dev cust,blk_size
+    part 1                  ; len blob_dev blk_size cust
+    pair 2                  ; len cust,blk_size,blob_dev
+    push k_writer_init      ; len cust,blk_size,blob_dev k_writer_init
+    actor create            ; len k=k_writer_init.cust,blk_size,blob_dev
+    pair 1                  ; k,len
+    state 0                 ; k,len blob_dev
+    ref std.send_msg
+
+k_writer_init:              ; cust,blk_size,blob_dev <- blob
+    msg 0                   ; blob
+    typeq #actor_t          ; is_cap(blob)
+    if_not writer_init_fail ; --
+    state -2                ; blob_dev
+    msg 0                   ; blob_dev blob
+    push wr_blob            ; blob_dev blob wr_blob
+    actor create            ; blob_dev first=wr_blob.blob
+    state 2                 ; blob_dev first size=blk_size
+    pick 2                  ; blob_dev first size first
+    push 0                  ; blob_dev first size first ofs=0
+    pair 4                  ; ofs,first,size,first,blob_dev
+    push writer             ; ofs,first,size,first,blob_dev writer
+    actor become            ; --
+    actor self              ; SELF
+    state 1                 ; SELF cust
+    ref std.send_msg
+writer_init_fail:           ; --
+    push #?                 ; #?
+    state 1                 ; #? cust
+    ref std.send_msg
+
+wr_blob:                    ; blob <- cust,len | cust,next | cust,ofs,data
+    msg 1                   ; cust
+    typeq #actor_t          ; is_cap(cust)
+    if_not std.abort        ; --
+    msg -1                  ; req
+    typeq #fixnum_t         ; is_fix(req)
+    if wr_slice             ; --
+    msg -1                  ; req
+    typeq #actor_t          ; is_cap(req)
+    if wr_pair              ; --
+    msg -1                  ; req
+    typeq #pair_t           ; is_pair(req)
+    if_not std.abort        ; --
+wr_write:                   ; write into blob
+    msg 0                   ; cust,ofs,data
+    state 0                 ; cust,ofs,data blob
+    ref std.send_msg
+wr_slice:                   ; convert to blob.slice
+;    msg 0                   ; cust,len
+    state 0                 ; blob
+    msg -1                  ; blob len
+    push 0                  ; blob len base=0
+    pair 2                  ; base,len,blob
+    push blob.slice         ; base,len,blob slice
+    actor become            ; --
+    actor self              ; SELF
+    msg 1                   ; SELF cust
+    ref std.send_msg
+wr_pair:                    ; convert to blob.pair
+;    msg 0                   ; cust,next
+    msg -1                  ; tail=next
+    state 0                 ; tail head=blob
+    pair 1                  ; head,tail
+    push blob.pair          ; head,tail pair
+    actor become            ; --
+    msg 0                   ; cust,next
+    part 1                  ; next cust
+    ref std.send_msg
+
+writer:                     ; ofs,blob,size,blobs,blob_dev <- can,cb,req | ok,cb | (can,cb,req),blob''
+    msg 0                   ; msg
+    typeq #pair_t           ; is_pair(msg)
+    if_not std.abort        ; --
+    msg 1                   ; (can,cb,req)
+    typeq #pair_t           ; is_pair((can,cb,req))
+    if writer_grown         ; --
+    msg -1                  ; cb
+    typeq #actor_t          ; is_cap(cb)
+    if writer_done          ; --
+    msg -2                  ; req
+    eq #?                   ; req==#?
+    if writer_read          ; --
+    msg -2                  ; req
+    typeq #fixnum_t         ; is_fix(req)
+    if writer_write         ; --
+    ref std.abort
+
+writer_read:                ; --
+    state 1                 ; len=ofs
+    state 4                 ; len blobs
+    msg 2                   ; len blobs cb
+    pair 1                  ; len cb,blobs
+    push writer_stone       ; len cb,blobs writer_stone
+    actor create            ; len cust=writer_stone.cb,blobs
+    pair 1                  ; cust,len
+    state 2                 ; cust,len blob
+    ref std.send_msg
+writer_stone:               ; cb,blobs <- slice
+    state -1                ; blobs
+    push #t                 ; blobs #t
+    pair 1                  ; #t,blobs
+    state 1                 ; #t,blobs cb
+    ref std.send_msg
+
+writer_write:               ; --
+    state 1                 ; ofs
+    state 3                 ; ofs size
+    cmp lt                  ; ofs<size
+    if_not writer_grow      ; --
+    msg -2                  ; data
+    state 1                 ; data ofs
+    actor self              ; data ofs SELF
+    msg 2                   ; data ofs SELF cb
+    pair 1                  ; data ofs cb,SELF
+    push k_blob_w           ; data ofs cb,SELF k_blob_w
+    actor create            ; data ofs cust=k_blob_w.wr,cb
+    pair 2                  ; cust,ofs,data
+    state 2                 ; cust,ofs,data blob
+    ref std.send_msg
+
+writer_done:                ; --
+    msg 1                   ; ok
+    if writer_ok            ; --
+    push #?                 ; #?
+    push #f                 ; #? #f
+    pair 1                  ; #f,#?
+    msg -1                  ; #f,#? cb
+    ref std.send_msg
+writer_ok:                  ; --
+    state 0                 ; ofs,blob,size,blobs,blob_dev
+    part 1                  ; blob,size,blobs,blob_dev ofs
+    push 1                  ; blob,size,blobs,blob_dev ofs 1
+    alu add                 ; blob,size,blobs,blob_dev ofs+1
+    pair 1                  ; ofs+1,blob,size,blobs,blob_dev
+    push writer             ; ofs+1,blob,size,blobs,blob_dev writer
+    actor become            ; --
+    push #?                 ; #?
+    push #t                 ; #? #t
+    pair 1                  ; #t,#?
+    msg -1                  ; #t,#? cb
+    ref std.send_msg
+
+writer_grow:                ; --
+    state 3                 ; len=size
+    state 0                 ; len state=ofs,blob,size,blobs,blob_dev
+    msg 0                   ; len state msg=can,cb,req
+    actor self              ; len state msg wr=SELF
+    pair 2                  ; len wr,msg,state
+    push k_writer_grow      ; len wr,msg,state k_writer_grow
+    actor create            ; len k=k_writer_grow.wr,msg,state
+    pair 1                  ; k,len
+    state -4                ; k,len blob_dev
+    ref std.send_msg
+k_writer_grow:              ; wr,(can,cb,req),ofs,blob,size,blobs,blob_dev <- blob'
+    msg 0                   ; blob'
+    push wr_blob            ; blob' wr_blob
+    actor create            ; next=wr_blob.blob'
+    state 0                 ; next state
+    push k_writer_grow2     ; next state k_writer_grow2
+    actor create            ; next k=k_writer_grow2.state
+    pair 1                  ; k,next
+    state 4                 ; k,next blob
+    ref std.send_msg
+k_writer_grow2:             ; wr,(can,cb,req),ofs,blob,size,blobs,blob_dev <- blob''
+    state 0                 ; wr,(can,cb,req),ofs,blob,size,blobs,blob_dev
+    part 2                  ; ofs,blob,size,blobs,blob_dev (can,cb,req) wr
+    msg 0                   ; ... (can,cb,req) wr blob''
+    roll 3                  ; ... wr blob'' (can,cb,req)
+    pair 1                  ; ... wr (can,cb,req),blob''
+    roll 2                  ; ... (can,cb,req),blob'' wr
+    ref std.send_msg
+
+writer_grown:               ; --
+    state -2                ; size,blobs,blob_dev
+    msg -1                  ; size,blobs,blob_dev blob''
+    push 0                  ; size,blobs,blob_dev blob'' ofs=0
+    pair 2                  ; ofs,blob'',size,blobs,blob_dev
+    push writer             ; ofs,blob'',size,blobs,blob_dev writer
+    actor become            ; --
+    msg 1                   ; (can,cb,req)
+    actor self              ; (can,cb,req) SELF
+    ref std.send_msg
+
+;
+; copy stream `in` to stream `out`
+; sending the final `result` to `cb`
+;
+stream_copy:                ; cb,out,in <- result
+    msg 1                   ; ok
+    if_not stream_end       ; --
+
+    msg -1                  ; value
+    eq #nil                 ; value==#nil
+    if stream_end           ; --
+
+    msg -1                  ; value
+    typeq #fixnum_t         ; is_fix(value)
+    if stream_write         ; --
+
+stream_read:                ; --
+    push #?                 ; #?
+    actor self              ; #? callback=SELF
+    push #?                 ; #? callback to_cancel=#?
+    pair 2                  ; req=to_cancel,callback,#?
+    state -2                ; req in
+    ref std.send_msg
+
+stream_write:               ; --
+    msg -1                  ; char
+    actor self              ; char callback=SELF
+    push #?                 ; char callback to_cancel=#?
+    pair 2                  ; req=to_cancel,callback,char
+    state 2                 ; req out
+    ref std.send_msg
+
+stream_end:                 ; --
+    msg 0                   ; result
+    state 1                 ; result cb
+    ref std.send_msg
+
+;
+; blob interface to a blob-stream
+;
+
+blobstr:                    ; blob,str,cb <- ok,blob' | cust | cust,ofs | cust,ofs,data | base',len',cust
+    msg 1                   ; ok
+    eq #t                   ; ok==#t
+    if blobstr_ok           ; --
+    msg 1                   ; ok
+    eq #f                   ; ok==#f
+    if blobstr_done         ; --
+    msg 0                   ; msg
+    state 1                 ; msg blob
+    ref std.send_msg
+blobstr_ok:                 ; --
+    msg -1                  ; blob'
+    typeq #actor_t          ; is_cap(blob')
+    if_not blobstr_done     ; --
+    state 0                 ; blob,str,cb
+    part 1                  ; str,cb blob
+    dup 1                   ; str,cb blob blob
+    typeq #actor_t          ; str,cb blob is_cap(blob)
+    if blobstr_pair         ; str,cb blob
+    drop 1                  ; str,cb
+    msg -1                  ; str,cb blob'
+    ref blobstr_update
+blobstr_pair:               ; str,cb blob
+    msg -1                  ; str,cb blob blob'
+    roll 2                  ; str,cb blob' blob
+    pair 1                  ; str,cb blob,blob'
+    push blob.pair          ; str,cb blob,blob' pair
+    actor create            ; str,cb blob''=pair.blob,blob'
+blobstr_update:             ; str,cb blob''
+    pair 1                  ; blob'',str,cb
+    push blobstr            ; blob'',str,cb blobstr
+    actor become            ; --
+    push #?                 ; req=#?
+    actor self              ; req cb=SELF
+    push #?                 ; req cb can=#?
+    pair 2                  ; can,cb,req
+    state 2                 ; can,cb,req str
+    ref std.send_msg
+blobstr_done:               ; --
+    state -2                ; cb
+    typeq #actor_t          ; is_cap(cb)
+    if_not std.commit       ; --
+    msg 0                   ; ok,value
+    state -2                ; ok,value cb
+    ref std.send_msg
+
+;
+; read-stream of source-blobs
+;
+
+strsource:                  ; offset,size,blob <- can,cb,#? | (base,len,blob'),cb
+    msg 1                   ; (base,len,blob')
+    typeq #pair_t           ; is_pair((base,len,blob'))
+    if strsource_result     ; --
+    state 0                 ; offset,size,blob
+    part 2                  ; blob size offset
+    actor self              ; blob size offset SELF
+    msg 2                   ; blob size offset SELF cb
+    pair 1                  ; blob size offset cb,SELF
+    push k_strsource        ; blob size offset cb,SELF k_strsource
+    actor create            ; blob size offset cust=k_strsource.cb,SELF
+    roll -3                 ; blob cust len=size base=offset
+    pair 2                  ; blob base,len,cust
+    roll 2                  ; base,len,cust blob
+    ref std.send_msg
+strsource_result:           ; --
+    msg 1                   ; base,len,blob'
+    nth 2                   ; len
+    eq 0                    ; len==0
+    if strsource_done       ; --
+    state 0                 ; offset,size,blob
+    part 1                  ; size,blob offset
+    msg 1                   ; size,blob offset base,len,blob'
+    nth 2                   ; size,blob offset len
+    alu add                 ; size,blob offset+len
+    pair 1                  ; offset+len,size,blob
+    push strsource          ; offset+len,size,blob strsource
+    actor become            ; --
+    msg 1                   ; base,len,blob'
+    push blob.slice         ; base,len,blob' slice
+    actor create            ; blob''=slice.base,len,blob'
+strsource_send:             ; blob''
+    push #t                 ; blob'' #t
+    pair 1                  ; #t,blob''
+    msg -1                  ; #t,blob'' cb
+    ref std.send_msg
+strsource_done:             ; --
+    push #nil               ; blob''=#nil
+    ref strsource_send
+
+k_strsource:                ; cb,str <- base,len,blob'
+    state 1                 ; cb
+    msg 0                   ; cb base,len,blob'
+    pair 1                  ; (base,len,blob'),cb
+    state -1                ; (base,len,blob'),cb str
+    ref std.send_msg
+
+;
+; usage demonstration
+;
+
+;;; Example HTTP request
+http_request:
+;; GET /index.html HTTP/1.0
+    pair_t 'G'
+    pair_t 'E'
+    pair_t 'T'
+    pair_t ' '
+    pair_t '/'
+    pair_t 'i'
+    pair_t 'n'
+    pair_t 'd'
+    pair_t 'e'
+    pair_t 'x'
+    pair_t '.'
+    pair_t 'h'
+    pair_t 't'
+    pair_t 'm'
+    pair_t 'l'
+    pair_t ' '
+    pair_t 'H'
+    pair_t 'T'
+    pair_t 'T'
+    pair_t 'P'
+    pair_t '/'
+    pair_t '1'
+    pair_t '.'
+    pair_t '0'
+    pair_t '\r'
+    pair_t '\n'
+    ref #nil                ; size=26
+
+http_req_hdrs:
+;; Host: localhost
+    pair_t 'H'
+    pair_t 'o'
+    pair_t 's'
+    pair_t 't'
+    pair_t ':'
+    pair_t ' '
+    pair_t 'l'
+    pair_t 'o'
+    pair_t 'c'
+    pair_t 'a'
+    pair_t 'l'
+    pair_t 'h'
+    pair_t 'o'
+    pair_t 's'
+    pair_t 't'
+blankln:
+    pair_t '\r'
+    pair_t '\n'
+crlf:
+    pair_t '\r'
+    pair_t '\n'
+    ref #nil                ; size=19
+
+demo_blobstr:               ; {caps} <- blob
+    state 0                 ; {caps}
+    msg 0                   ; {caps} head=blob
+    pair 1                  ; head,{caps}
+    push k_demo_blobstr     ; head,{caps} demo=k_demo_blobstr
+    actor become            ; --
+;    msg 0                   ; tail=blob
+;    actor self              ; tail SELF
+;    ref std.send_msg
+    push http_req_hdrs      ; list=http_req_hdrs
+    actor self              ; list cust=SELF
+    pair 1                  ; cust,list
+    state 0                 ; cust,list {caps}
+    push dev.blob_key       ; cust,list {caps} blob_key
+    dict get                ; cust,list blob_dev
+    push blob.init          ; cust,list blob_dev init
+    actor create            ; cust,list init.blob_dev
+    ref std.send_msg
+k_demo_blobstr:             ; head,{caps} <- tail
+    state -1                ; {caps}
+    push k_demo_blobstr1    ; {caps} demo=k_demo_blobstr1
+    actor become            ; --
+    msg 0                   ; tail
+    state 1                 ; tail head
+    pair 1                  ; head,tail
+    push blob.pair          ; head,tail pair
+    actor create            ; blob=pair.head,tail
+    actor self              ; blob SELF
+    ref std.send_msg
+k_demo_blobstr1:            ; {caps} <- blob
+    actor self              ; cb=SELF
+    msg 0                   ; cb blob
+;    push 1024               ; cb blob size=1024
+    push 10                 ; cb blob size=10
+    push 0                  ; cb blob size offset=0
+    pair 2                  ; cb offset,size,blob
+    push strsource          ; cb offset,size,blob strsource
+    actor create            ; cb str=strsource.offset,size,blob
+
+    pick -2                 ; str cb str
+    push #nil               ; str cb str blob=#nil
+    pair 2                  ; str blob,str,cb
+    push blobstr            ; str blob,str,cb blobstr
+    actor create            ; str blob'=blobstr.blob,str,cb
+
+    state 0                 ; str blob' {caps}
+    pick 2                  ; str blob' {caps} blob'
+    pair 1                  ; str blob' blob',{caps}
+    push k_demo_blobstr2    ; str blob' blob',{caps} k_demo_blobstr2
+    actor become            ; str blob'
+
+    push #?                 ; str blob' req=#?
+    roll 2                  ; str req cb=blob'
+    push #?                 ; str req cb can=#?
+    pair 2                  ; str can,cb,req
+    roll 2                  ; can,cb,req str
+    ref std.send_msg
+k_demo_blobstr2:            ; blob',{caps} <- ok,value
+    state -1                ; {caps}
+    push k_demo_blobstr9    ; {caps} k_demo_blobstr9
+    actor become            ; --
+    state 1                 ; blob'
+    actor self              ; blob' SELF
+    ref std.send_msg
+k_demo_blobstr9:            ; {caps} <- blob
+    msg 0                   ; blob
+    state 0                 ; blob {caps}
+;    push demo_debug         ; blob {caps} demo=demo_debug
+;    push demo_size          ; blob {caps} demo=demo_size
+    push demo_print         ; blob {caps} demo=demo_print
+;    push demo_source        ; blob {caps} demo=demo_source
+    actor create            ; blob demo.{caps}
+    ref std.send_msg
+
+demo_strsource:             ; {caps} <- blob
+    state 0                 ; {caps}
+    msg 0                   ; {caps} head=blob
+    pair 1                  ; head,{caps}
+    push k_demo_strsource   ; head,{caps} demo=k_demo_strsource
+    actor become            ; --
+;    msg 0                   ; tail=blob
+;    actor self              ; tail SELF
+;    ref std.send_msg
+    push http_req_hdrs      ; list=http_req_hdrs
+    actor self              ; list cust=SELF
+    pair 1                  ; cust,list
+    state 0                 ; cust,list {caps}
+    push dev.blob_key       ; cust,list {caps} blob_key
+    dict get                ; cust,list blob_dev
+    push blob.init          ; cust,list blob_dev init
+    actor create            ; cust,list init.blob_dev
+    ref std.send_msg
+k_demo_strsource:           ; head,{caps} <- tail
+    state -1                ; {caps}
+    push k_demo_strsource1  ; {caps} demo=k_demo_strsource1
+    actor become            ; --
+    msg 0                   ; tail
+    state 1                 ; tail head
+    pair 1                  ; head,tail
+    push blob.pair          ; head,tail pair
+    actor create            ; blob=pair.head,tail
+    actor self              ; blob SELF
+    ref std.send_msg
+k_demo_strsource1:          ; {caps} <- blob
+    msg 0                   ; blob
+;    push 1024               ; blob size=1024
+    push 10                 ; blob size=10
+    push 0                  ; blob size offset=0
+    pair 2                  ; offset,size,blob
+    push strsource          ; offset,size,blob strsource
+    actor create            ; str=strsource.offset,size,blob
+    push #?                 ; str req=#?
+    state 0                 ; str req {caps}
+    pick 3                  ; str req {caps} str
+    pair 1                  ; str req str,{caps}
+    push k_demo_strsource2  ; str req str,{caps} k_demo_strsource2
+    actor create            ; str req cb=k_demo_strsource2.str,{caps}
+    push #?                 ; str req cb can=#?
+    pair 2                  ; str can,cb,req
+    roll 2                  ; can,cb,req str
+    ref std.send_msg
+k_demo_strsource2:          ; str,{caps} <- ok,blob'
+    msg 1                   ; ok
+    eq #t                   ; ok==#t
+    if_not k_demo_strsource3; --
+    msg -1                  ; blob'
+    typeq #actor_t          ; is_cap(blob')
+    if_not k_demo_strsource3; --
+
+    push #?                 ; req=#?
+    actor self              ; req cb=SELF
+    push #?                 ; req cb can=#?
+    pair 2                  ; can,cb,req
+    state 1                 ; can,cb,req str
+    actor send              ; --
+
+    msg -1                  ; blob'
+    state -1                ; blob' {caps}
+;    push demo_debug         ; blob' {caps} demo=demo_debug
+;    push demo_size          ; blob' {caps} demo=demo_size
+;    push demo_print         ; blob' {caps} demo=demo_print -- CAUTION: scrambled output
+    push demo_source        ; blob' {caps} demo=demo_source
+    actor create            ; blob' demo.{caps}
+    ref std.send_msg
+k_demo_strsource3:          ; --
+    msg 0                   ; ok,blob'
+    state -1                ; ok,blob' {caps}
+    push dev.debug_key      ; ok,blob' {caps} debug_key
+    dict get                ; ok,blob' debug_dev
+    ref std.send_msg
+
+demo_writer:                ; {caps} <- blob
+    msg 0                   ; blob
+    state 0                 ; blob {caps}
+    push k_demo_writer      ; blob {caps} k_demo_writer
+    actor create            ; blob cust=k_demo_print.{caps}
+    pair 1                  ; cust,blob
+    push #?                 ; cust,blob #?
+    push reader_factory     ; cust,blob #? reader_factory
+    actor create            ; cust,blob reader_factory._
+    ref std.send_msg
+k_demo_writer:              ; {caps} <- in
+    state 0                 ; {caps}
+    msg 0                   ; {caps} in
+    pair 1                  ; in,{caps}
+    push k_demo_writer2     ; in,{caps} k_demo_writer2
+    actor become            ; --
+
+    push 10                 ; blk_size=10
+;    push 7                  ; blk_size=7
+    actor self              ; blk_size cust=SELF
+    pair 1                  ; cust,blk_size
+
+    state 0                 ; cust,blk_size {caps}
+    push dev.blob_key       ; cust,blk_size {caps} blob_key
+    dict get                ; cust,blk_size blob_dev
+    push writer_factory     ; cust,blk_size blob_dev writer_factory
+    actor create            ; cust,blk_size writer_factory.blob_dev
+    ref std.send_msg
+k_demo_writer2:             ; in,{caps} <- out
+    state -1                ; {caps}
+    msg 0                   ; {caps} out
+    pair 1                  ; out,{caps}
+    push k_demo_writer3     ; out,{caps} k_demo_writer3
+    actor become            ; --
+
+    state 1                 ; in
+    msg 0                   ; in out
+    actor self              ; in out cb=SELF
+    pair 2                  ; cb,out,in
+    push stream_copy        ; cb,out,in stream_copy
+    actor create            ; tgt=stream_copy.cb,out,in
+    ref tgt_start
+k_demo_writer3:             ; out,{caps} <- result
+    state -1                ; {caps}
+    push k_demo_writer4     ; {caps} k_demo_writer4
+    actor become            ; --
+
+    push #?                 ; #?
+    actor self              ; #? cb=SELF
+    push #?                 ; #? cb can=#?
+    pair 2                  ; can,cb,#?
+    state 1                 ; can,cb,#? out
+    ref std.send_msg
+k_demo_writer4:           ; {caps} <- result
+    state 0                 ; {caps}
+;    push demo_debug         ; {caps} demo=demo_debug
+;    push demo_size          ; {caps} demo=demo_size
+    push demo_print         ; {caps} demo=demo_print
+;    push demo_source        ; {caps} demo=demo_source
+    actor become            ; --
+
+    msg -1                  ; blob
+    actor self              ; blob SELF
+    ref std.send_msg
+
+demo_composite:             ; {caps} <- blob
+    state 0                 ; {caps}
+    push k_demo_composite   ; {caps} demo=k_demo_composite
+    actor become            ; --
+
+    msg 0                   ; blob
+    push 2                  ; blob len=2
+    push 24                 ; blob len base=24
+    pair 2                  ; base,len,blob
+    push blob.slice         ; base,len,blob slice
+    actor create            ; tail=slice.base,len,blob
+
+    msg 0                   ; tail blob
+    push 11                 ; tail blob len=11
+    push 4                  ; tail blob len base=4
+    pair 2                  ; tail base,len,blob
+    push blob.slice         ; tail base,len,blob slice
+    actor create            ; tail head=slice.base,len,blob
+
+    pair 1                  ; head,tail
+    push blob.pair          ; head,tail pair
+    actor create            ; blob=pair.head,tail
+
+    actor self              ; blob SELF
+    ref std.send_msg
+k_demo_composite:           ; {caps} <- blob
+    state 0                 ; {caps}
+;    push demo_size          ; {caps} demo=demo_size
+;    push demo_print         ; {caps} demo=demo_print
+    push demo_source        ; {caps} demo=demo_source
+    actor become            ; --
+    msg 0                   ; blob
+    actor self              ; blob SELF
+    ref std.send_msg
+
+demo_pair:                  ; {caps} <- blob
+    state 0                 ; {caps}
+    msg 0                   ; {caps} head=blob
+    pair 1                  ; head,{caps}
+    push k_demo_pair        ; head,{caps} demo=k_demo_pair
+    actor become            ; --
+demo_pair_aliased:
+;    msg 0                   ; tail=blob
+;    actor self              ; tail SELF
+;    ref std.send_msg
+demo_pair_composed:
+    push http_req_hdrs      ; list=http_req_hdrs
+    actor self              ; list cust=SELF
+    pair 1                  ; cust,list
+    state 0                 ; cust,list {caps}
+    push dev.blob_key       ; cust,list {caps} blob_key
+    dict get                ; cust,list blob_dev
+    push blob.init          ; cust,list blob_dev init
+    actor create            ; cust,list init.blob_dev
+    ref std.send_msg
+k_demo_pair:                ; head,{caps} <- tail
+    state -1                ; {caps}
+    push k_demo_pair1       ; {caps} demo=k_demo_pair1
+    actor become            ; --
+    msg 0                   ; tail
+    state 1                 ; tail head
+    pair 1                  ; head,tail
+    push blob.pair          ; head,tail pair
+    actor create            ; blob=pair.head,tail
+    actor self              ; blob SELF
+    ref std.send_msg
+k_demo_pair1:               ; {caps} <- blob
+    state 0                 ; {caps}
+    msg 0                   ; {caps} blob
+    pair 1                  ; blob,{caps}
+    push k_demo_pair2       ; blob,{caps} demo=k_demo_pair2
+    actor become            ; --
+    push '1'                ; data='1'
+    push 49                 ; data ofs=49
+    actor self              ; data ofs cust=SELF
+    pair 2                  ; cust,ofs,data
+    msg 0                   ; cust,ofs,data blob
+    ref std.send_msg
+k_demo_pair2:               ; blob,{caps} <- wr_ok
+    state 0                 ; blob,{caps}
+    push k_demo_pair3       ; blob,{caps} demo=k_demo_pair3
+    actor become            ; --
+    push '\t'               ; data='\t'
+    push 3                  ; data ofs=3
+    actor self              ; data ofs cust=SELF
+    pair 2                  ; cust,ofs,data
+    state 1                 ; cust,ofs,data blob
+    ref std.send_msg
+k_demo_pair3:               ; blob,{caps} <- wr_ok
+    state -1                ; {caps}
+;    push demo_size          ; {caps} demo=demo_size
+    push demo_print         ; {caps} demo=demo_print
+;    push demo_source        ; {caps} demo=demo_source
+    actor become            ; --
+    state 1                 ; blob
+    actor self              ; blob SELF
+    ref std.send_msg
+
+demo_slice:                 ; {caps} <- blob
+    state 0                 ; {caps}
+;    push demo_size          ; {caps} demo=demo_size
+    push demo_print         ; {caps} demo=demo_print
+;    push demo_source        ; {caps} demo=demo_source
+    actor become            ; --
+    msg 0                   ; blob
+    push 11                 ; blob len=11
+    push 4                  ; blob len base=4
+    pair 2                  ; base,len,blob
+    push blob.slice         ; base,len,blob slice
+    actor create            ; blob=slice.base,len,blob
+    actor self              ; blob SELF
+    ref std.send_msg
+
+demo_debug:                 ; {caps} <- blob
+    msg 0                   ; blob
+    state 0                 ; blob {caps}
+    push dev.debug_key      ; blob {caps} debug_key
+    dict get                ; blob debug_dev
+    ref std.send_msg
+
+demo_size:                  ; {caps} <- blob
+    state 0                 ; {caps}
+    push dev.debug_key      ; {caps} debug_key
+    dict get                ; cust=debug_dev
+    msg 0                   ; debug_dev blob
+    ref std.send_msg
+
+demo_print:                 ; {caps} <- blob
+    msg 0                   ; blob
+    state 0                 ; blob {caps}
+    push k_demo_print       ; blob {caps} k_demo_print
+    actor create            ; blob cust=k_demo_print.{caps}
+    pair 1                  ; cust,blob
+    push #?                 ; cust,blob #?
+    push reader_factory     ; cust,blob #? reader_factory
+    actor create            ; cust,blob reader_factory._
+    ref std.send_msg
+k_demo_print:               ; {caps} <- in
+    msg 0                   ; in
+    state 0                 ; in {caps}
+    push dev.io_key         ; in {caps} io_key
+    dict get                ; in out=io_dev
+    state 0                 ; in out {caps}
+    push dev.debug_key      ; in out {caps} debug_key
+    dict get                ; in out cb=debug_dev
+    pair 2                  ; cb,out,in
+    push stream_copy        ; cb,out,in stream_copy
+    actor create            ; tgt=stream_copy.cb,out,in
+tgt_start:                  ; tgt
+    push #?                 ; tgt value=#?
+    push #t                 ; tgt #? ok=#t
+    pair 1                  ; tgt result=ok,value
+    roll 2                  ; result tgt
+    ref std.send_msg
+
+demo_source:                ; {caps} <- blob
+    state 0                 ; {caps}
+    push dev.debug_key      ; {caps} debug_key
+    dict get                ; cust=debug_dev
+    push 4096               ; cust len=4096
+;    push 13                 ; cust len=13
+    push 0                  ; cust len base=0
+;    push 7                  ; cust len base=7
+;    push 42                 ; cust len base=42
+    pair 2                  ; base,len,cust
+    msg 0                   ; base,len,cust blob
+    ref std.send_msg
+
+boot:                       ; _ <- {caps}
+    push http_request       ; list=http_request
+    msg 0                   ; list {caps}
+;    push demo_debug         ; list {caps} demo=demo_debug
+;    push demo_size          ; list {caps} demo=demo_size
+;    push demo_print         ; list {caps} demo=demo_print
+;    push demo_source        ; list {caps} demo=demo_source
+;    push demo_slice         ; list {caps} demo=demo_slice
+;    push demo_pair          ; list {caps} demo=demo_pair
+;    push demo_composite     ; list {caps} demo=demo_composite
+;    push demo_writer        ; list {caps} demo=demo_writer
+;    push demo_strsource     ; list {caps} demo=demo_strsource
+    push demo_blobstr       ; list {caps} demo=demo_blobstr
+    actor create            ; list cust=demo.{caps}
+    pair 1                  ; cust,list
+    msg 0                   ; cust,list {caps}
+    push dev.blob_key       ; cust,list {caps} blob_key
+    dict get                ; cust,list blob_dev
+    push blob.init          ; cust,list blob_dev init
+    actor create            ; cust,list init.blob_dev
+    ref std.send_msg
+
+.export
+    reader_factory
+    writer_factory
+    stream_copy
+    blobstr
+    strsource
+    boot