The COLOUR config.sys statement causes screen corruption on MDA displays

[igully]

While it is obvious that the COLOUR statement should be taken advantage when used on EGA or better display, on MDA displays, instead of being ignored or having some fallback mechanism, it causes screen corruption.

Issue was reproduced on an 86Box config. I just simply added the supposedly safe COLOUR=7,0,0 to a config.sys that had menu options, but all hell broke loose. Commenting it, solved the issue.

I have not tested this issue to happen on CGA displays, but this could also potentially be the case.

[boeckmann]

hell broke loose

We do not want this :) I will have a look at this next weekend.

[boeckmann]

Can you upload your config.sys? The COLOUR=7,0,0 does not seem to be a problem by itself.

[igully]

I am uploading the entire disk image with its config file too.

I can confirm that the issue occurs both in MDA and CGA. With an EGA or VGA config it simply works as it should.
Curiously as I modified config files, the display error moved somewhere else.

If you try this floppy, on IBM MDA and IBM CGA displays, it will not display the config.sys menu I recreated.
System tested is an 8088 with 640 KB memory and a Magitronic B215 floppy controller on 86Box emulator

OLDDOS.zip

.

[boeckmann]

Strange, your image works for me on IBM-XT (1986), 256K RAM, MDA (86box) with either the Magitronic B215 and the IBM-XT floppy controller.

[boeckmann]

And also works with 640K "installed". Are you sure it has not something to do with your specific 86box build?

[igully]

I am using stable build 5.1 [build 7777].
It seems latest stable in 86Box is now 5.2.
I will update, retest and provide more feedback.

[igully]

Retested with the updated stable X86Box v5.2 [build 8000], presenting the same issue.
I am attaching pictures:

This is a "Generic XT clone" with IBM MDA, 640 KB RAM and a Magictronic B215 set to boot from the 360 KB floppy previously posted.