[mod.computers.vax] VAXstation VS100 ACP infinite-looping

WOLF@BBNG (Jerry Wolf) (03/04/86)

I wonder if anyone else out there, among the select few using the
VAXstation VS100, have observed a problem with the ACP going into
an infinite loop, which, since the ACP runs at a higher priority than
users, grabs almost the entire CPU?  It appears to be doing no i/o
or page faulting, just sits there.  If you have observed this problem,
do you have any insights or information on it?  (We're running VMS 4.1
with Release 1.1 of the VSTA software.)

We've seen this sort of thing both deterministically and apparently
randomly.  We've observed it only inside an application
that uses several pasteboards, some with many virtual displays pasted
on them.  The deterministic thing happened (8/85) when we were pasting
several displays on a pasteboard.  We appealed to DEC (not Colorado, but
some place in Atlanta? I think, that is (was?) for VAXstation problems,
eventually sending them the whole program package, which they were
able to use to recreate the problem.  They came up with no insight on
the problem, but observed that the problem didn't occur if we pasted
the displays in top-to-bottom order.  That was the extent of their help,
not truly satisfying in its comprehensiveness.

The other observances don't seem to be repeatable, but simply happen
sometime in the course of running this interactive program with
many pastebaords/displays/menus, etc.  We've only observed it a few times,
and it seems to be when the program is removing displays or pasteboards
from the screen.  I don't know that the causes are related, only that the
symptom (ACP looping forever) is similar.

ANyone else?