I've been asked for more info about the symptoms, and a stack trace, so here
goes:

I believe what happened here is that I was experimenting with CI command
files, trying to develop a slick way to embed non-CI information like JCL
code or awk scripts inside a command file, and have the command file read
itself to extract the embedded code.  Something like this:

  echo starting test script
  /bin/awk "'/start/,/end/'" <!HPFILE
  # start
  # junk lines
  # end
  echo test script complete

Well, anyway, upon running something like this it hung.  Here's a trace of
the BLKCB'ed process:

$1 ($119) nmdebug > PIN #417
$2 ($1a1) nmdebug > TRACE
     PC=a.0019870c enable_int+$2c
* 0) SP=4183a238 RP=a.002cca0c notify_dispatcher.block_current_process+$31c
  1) SP=4183a238 RP=a.002cee88 notify_dispatcher+$264
  2) SP=4183a1b8 RP=a.001c7174 sem_block.wait_for_resource+$1c4
  3) SP=4183a0b8 RP=a.001c7578 sem_block+$364
  4) SP=41839ff8 RP=a.003684a0 cb_shr_lock+$240
  5) SP=41839ef8 RP=a.0019fb54 shr_sem_lock+$14
  6) SP=41839db8 RP=a.00c306fc tm_close_common+$1b8
  7) SP=41839d70 RP=a.00bfa680 tm_ord_fix_buf_disc+$1e4
  8) SP=41838db0 RP=a.00b2b2e8 fclose_nm+$5e4
  9) SP=41838cf0 RP=a.00b2acd0 ?fclose_nm+$8
       export stub: a.00eab848 FCLOSE+$b8
  a) SP=41838a70 RP=a.00eab75c ?FCLOSE+$8
       export stub: a.00a8b960 cior_unredirect_special_file+$d8
  b) SP=418389b0 RP=a.00a8b840 cior_unredirect_io+$34
  c) SP=41838870 RP=a.00a7db24 command_interpret.handle_io_unredir+$c8
  d) SP=41838830 RP=a.00a7e82c command_interpret+$554
  e) SP=418386f0 RP=a.00a7e2a4 ?command_interpret+$8
       export stub: a.00a81e04 xeqcommand+$194
  f) SP=418380f0 RP=a.009108c0 exec_usercmd+$2d0
 10) SP=41838070 RP=a.009105bc ?exec_usercmd+$8
       export stub: a.00a7fb84 exec_cmdfile+$34
 11) SP=41836e30 RP=a.00a7fb1c ?exec_cmdfile+$8
       export stub: a.00a81028 try_cmdf_or_progf+$a0
 12) SP=41836db0 RP=a.00a7e704 command_interpret+$42c
 13) SP=41836930 RP=a.00a7e2a4 ?command_interpret+$8
       export stub: a.00a81e04 xeqcommand+$194
 14) SP=41836330 RP=a.00a81c5c ?xeqcommand+$8
       export stub: 144.000067dc main_ci+$64
 15) SP=418362b0 RP=144.0000751c PROGRAM+$290
 16) SP=41836230 RP=144.00000000
     (end of NM stack)
$3 ($1a1) nmdebug >
________________________________________________________
Jon Diercks * Systems Manager         Computing Services
[log in to unmask] (PGP available)     Anderson University
http://rowlf.csv.anderson.edu/        1100 East Fifth St
(317)641-4305 * FAX (317)641-3851     Anderson, IN 46012