[Info-vax] MPA105: and RWAST'd

[Jojimbo]

I've run into a problem that's new to me.  I have a batch job that
does a pipe command that lists out a bunch of data records and then
searches for a particular string.  The string is then parsed to pick
out a particular piece of data.  Relevant section from the log is
here:

$ feob 563,grp104/match=and | -
  (read sys$pipe line ; define/job/nolog search_result &line)
$ get = f$trnlnm( "search_result", "lnm$job",,,)
$ loc = f$locate("_PRT", get)
$ show sym get
  GET = "563 GRP104_BLUE_PRT   0  OPERATOR   08/01/2011
SORT AND PR
$ size = f$extract( loc+4, 4, get)
$ sho sym size
  SIZE = "   0"

This seems to work fine and the right record is found and the the
desired data is found.  (feob is a symbol for a command that produces
the data records).  The end of the batch log has the usual accounting
information but the job does not really complete and remains in a
RWAST state.  In SDA doing "show proc/channel/index=batch_job_index
shows:

Channel    CCB     Window     Status    Device/file accessed
-------    ---     ------     ------    --------------------
  0010  7FF78000  00000000              DSA300:
  0020  7FF78020  826BEF40              DSA300:[VMS
$COMMON.SYSEXE]LOGINOUT.EXE;1
  0030  7FF78040  00000000              MBA6521:
  0040  7FF78060  826C3C00              DSA300:[VMS
$COMMON.SYSMSG]CLIUTLMSG.EXE;
  0050  7FF78080  826BFFC0              DSA300:[VMS
$COMMON.SYSEXE]DCL.EXE;1 (sec
  0060  7FF780A0  826B4000              DSA300:[VMS
$COMMON.SYSLIB]DCLTABLES.EXE;

  Total number of open channels : 6.

There is a subprocess of this batch job that is in RWMBX state.  In
SDA the "show proc/chan" displays no channels marked as busy and two
channels for a device MPA105:   From DCL, "show dev/full MPA105:"
shows the Owner process as the batch job.

This whole situation is very puzzling.  The subprocess loooks to be
the first stage of the pipeline based on the .exe it's running.   But
I expect to see a busy channel for it's state to be RWMBX.
I guess the device MPA105: is sys$pipe and in fact it's full of data.
After thrashing around for quite a while I cleared things up by
opening the MPA105: device and reading all the data out of it with a
small script like this:

$ open/read input MPA105:
$ again:
$ read input line
$ show sym line
$ goto again

(I always do "set host 0" to be on a decnet link before doing things
like this in the event I need to get out cleanly with two control
Y's).  The data displayed by the script is the rest of the records
from the feob utility.  The records after the one that matched in the
search command in the pipeline are displayed by the script.  I use the
double control Y's and abort the DECnet link.  The batch job completes
and the subprocess disapears.

I'm wondering why there were no busy channels.  And what is MPA105
anyway?  Why did the batch log look like the job had completed?  And
most important is there some sysgen parameter (or UAF quota) that I
need to adjust to get this to complete normally?  DEFMBXBUFQUO? or
something else?

Regards, Jim