[fa.info-vax] Subprocesses and Allocated devices.

DEAN@engvax.UUCP (09/12/85)

Several people recently mentioned that they were having problems
with a subprocess that allocated a device, then mounted it, dismounted it,
and then tried to deallocate the device.  I have a friend at Xerox who
had the same problem, and sent in a SPR about it.  Surprisingly enough,
he got a reply.  Text follows.

                       SPR ANSWER FORM

SPR Number:  11CS01400

System:      VMS
Version:     4.1

PROBLEM STATEMENT:

    If a user executes the following sequence of commands:

     $ SPAWN
     $ ALLOCATE HSC015$MUA0
     $ MOUNT HSC015$MUA0 DOOF
     $ DISMOUNT HSC015$MUA0

the subprocess which originally allocated the tape drive no longer
has possession of it.  Instead, the tape drive is allocated to the
parent process.  This inhibits use of the tape drive by the child
after the first mounting.

RESPONSE:

    Thank you for your SPR.

    In VAX/VMS Version 4.0, we made a deliberate change to MOUNT to
make the default (private) mount be job wide, rather than per process.
This was done in response to substantial customer input that this was
more useful for the majority of applications.  Having ownership of the
device not revert to the subprocess is an unfortunate asymmetry that
results from this change.  In particular, it means that a sequence of
ALLOCATE, MOUNT, DISMOUNT, and DEALLOCATE from a subprocess does not
work.  We will investigate correcting this problem in a future update
to VAX/VMS.


                       END OF SPR RESPONSE

So DEC knows about it, and maybe they will fix it.

    Dean Stephan
    Hughes Aircraft Company