Stan wrote after I wrote:
 
>> I had a FAFFing hang late last night -- PIN 17 ran away with the CPU.
>>
>> Does anybody know if pin 17 has special significance (& if so, what)?
 
>Well, it depends on several things:
>
>   1) is that decimal 17 (#17), or hex 17 ($17)?
 
decimal.
 
>   2) how many volume sets do you have; how many mirrored volume sets?
 
Two, none are mirrored.
 
>   3) unknown vagaries of the PIN god :)
 
<snip>
>
>So, to see what PIN #17 is now, do one or more of the following:
 
<snip>
 
>   2) :SHOWPROC 17; SYSTEM
 
Tried it, doesn't tell me much:
     Wayne:showproc 17;system
     QPRI  CPUTIME   STATE  JOBNUM  PIN  (PROGRAM) STEP
 
     A13 * 0:00.007  WAIT           17   (..)
 
>   3) :DEBUG
>      pin #17; tr, i, d     /* or, possibly:   pin #17; cm; tr
 
$4 ($9b) nmdebug > pin #17;tr,i,d
       PC=a.0013a6e8 enable_int+$2c
NM* 0) SP=40331670 RP=a.00ec3d8c
notify_dispatcher.block_current_process+$480
NM  1) SP=40331670 RP=a.00ec7798 notify_dispatcher+$254
NM  2) SP=403315e0 RP=a.003ff2fc wait_for_active_port+$ec
NM  3) SP=40331500 RP=a.003ffd94 receive_from_port+$320
NM  4) SP=403314a0 RP=a.00348490 receive_msg+$244
NM  5) SP=40331340 RP=a.0038f254 io_mgr_process+$290
NM  6) SP=40331240 RP=a.008e9248 outer_block+$fc
NM  7) SP=403310d0 RP=a.00000000 _traplib_version
     (end of NM stack)
$5 ($11) nmdebug >
 
 
>
>   5) Use an MI-based tool like SOS/3000 from LPS, or Glance/iX from HP.
 
All SOS could tell me is that it's a "system process"...