[comp.unix.i386] DOS Norton NCD under VP/ix causes panic

raymond@ele.tue.nl (Raymond Nijssen) (05/31/90)

I have a 386 running ISC 386/ix release 2.0.1, and AT&T's Simultask (=VP/ix)
version 2.0, and it runs quite stable, except when I start Norton's NCD
program (the DOS version under VP/ix): it first scans the entiry dirtree
of my (native) DOS partion, which is mounted by the line
mount -f DOS /dev/dsk/0p1 /dos
Second, it finds way too much directory entries, and then, the HD controller
activity LED comes solid for a number of seconds, soon followed by a
panic: kernel mode trap 0x000000E, a registerdump, etcetera.

I wonder how a program like NCD, which uses, as it seems to me, only MS-DOS
calls, can cause not only the VP/ix application to crash, which would be
comparably bearable, but also the whole system. Minor detail: the DOS      
partition was damaged severely, and could only be fixed after a number of
manual fixes and restores.

I would like to know if other users have the same experience and how 
these instabilities can be avoided in the future.

Greetings,
Raymond.

-----------------------------------------------------------------------------
raymond@ele.tue.nl
Raymond Nijssen

johnl@esegue.segue.boston.ma.us (John R. Levine) (05/31/90)

In article <505@al.ele.tue.nl> raymond@ele.tue.nl (Raymond Nijssen) writes:
>I have a 386 running ISC 386/ix release 2.0.1, and AT&T's Simultask (=VP/ix)
>version 2.0, and it runs quite stable, except when I start Norton's NCD
>program (the DOS version under VP/ix): it [crashes in an unpleasant way.]

Hmmn, I didn't know the AT&T vp/ix even worked with 386/ix.  In any event,
the problem may well be the familiar NDOSINODE one.  The standard table of
in memory DOS pseudo inodes is too small, to fix it you run /etc/kconfig and
give it a new parameter NDOSINODE and set it to about 400, then build and
install a new kernel.

However, there is another approach you might try.  The way you are getting
from vp/ix to the DOS disk is extremely convoluted: first Unix is simulating
Unix files on top of the DOS file system, then vp/ix is using simulated remote
networked DOS files on top of the simulated Unix files on the DOS file system.
vp/ix, being DOS after all, can get to the DOS file system directly.  Unmount
the /dos partition and add to your vpix.cnf file a line like

D		/dev/dsk/0p0

and when you use vp/ix, your D: disk will be your actual DOS partition
unconfused by two levels of simulation.  Avoid direct disk access from vp/ix
at the same time the disk is mounted, there's no locking between the two and
the disk can get scrambled.

Shameless commercial: Even better, install the new Norton Utilities for Unix
and use the Unix ncd command which works on a mounted /dos partition just like
on any other part of the file tree.

-- 
John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 864 9650
johnl@esegue.segue.boston.ma.us, {ima|lotus|spdcc}!esegue!johnl
Marlon Brando and Doris Day were born on the same day.