rde@ukc.ac.uk (R.D.Eager) (11/12/86)
We have a lot of PC clones running MS-DOS 3.2, and are having problems
with crashes.
Scenario:
Install the KEYBUK program (yes, it only fails with this installed); bet
you didn't bother to test this, Microsoft!
Run a program that doesn't read input for a while (e.g. FORMAT a floppy).
Hold down a key on the keyboard.
Result:
DOS crashes with `Internal Stack Overflow'
Now, I know about the STACKS= (STACK=?) parameter in CONFIG.SYS; it
still crashes when I use STACKS=64,512 (the max, I believe). I don't
think this is a solution.
I think the keyboard on this clone generates characters about 10% faster
than a real PC. The supplier says he can detune the keyboards to fix the
problem, but this is inconvenient (and A HORRIBLE KLUDGE).
The cause is clearly KEYBUK. It isn't handling interrupts correctly? I
checked the code to make sure it has done a CLI before acknowledging the
interrupt at the 8259, and indeed patched it in one case where that
wasn't so. All paths from the acknowledgement (20H to port 20H) to the
IRET run with all interrupts off.
Perhaps a higher priority interrupt source generates multiple interrupts
and eventually they blow the stack?
Any ideas, anyone?
--
Bob Eager
rde@ukc.UUCP
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