Internal Stack Overflow

[ForNext]

Hi all,

I recently bought me an IBM 5160 that I was able to put to use after a low-level format of the harddisk and installing MS-DOS 3.3 on it.
However, I noticed an 'Internal Stack Overflow' after operations for some time.



At first I suspected the keyboard (interrupt) because of the output on the screen (all 'Y' characters), but I found out that wasn't the problem.
After that I dove into the bios and from there into the timer interrupt because I suspected the cause lay there.
I checked the interrupt table and routines associated with those and saw nothing starnge in the IRQ8 (timer) but some perculiar code in the 0x1C routine.



I wrote a program to put that code into a binary file and checked this with IDA.





It looks like there is a (bios)program that attaches itself to Int0x1C and calls 5 times on Int9 (keyboard interrupt).
If I change the code and put an IRET right at the start everything is ok.

Will have to dig further into it (detaching hardware and see what happens).

But I was wondering if anybody is familiair with this problem.

Best regards,
Dirk.

 

[ForNext]

Found it, not a hardware issue but an old virus called 'strain of keypress '.
Have to check where it originates from and warn winworldpc.com, all my programs come from over there ;-)

Best regards,
Dirk

 

[modem7]

Hi all,

Welcome to these forums.

At first I suspected the keyboard (interrupt) because of the output on the screen (all 'Y' characters), but I found out that wasn't the problem.

Because you tried a different keyboard ?

But I was wondering if anybody is familiar with this problem.

I have been a member of these forums since 2006, focusing on PC related posts. I do not remember anyone posting the symptom you describe (a bunch of Y's followed by 'Internal stack overflow').

Have you ruled out a virus ?

 

[ForNext]

Thanks for the welcome.

Disconnected the keyboard and the problem persisted.

Because it is an old pc and I just got it my first thought was not a virus.
So been quite busy chasing this problem, though it has been very educational digging into it

Best regards,
Dirk.