First post, by scruit

User metadata
Rank Newbie

Working 'Uncle Sherman', my "Unisys"-branded Mitsibishi MP-3200 386...

CheckIT 1 running on Dos3.3 crashes when CPU testing reaches the protected mode test.

CheckIT 3 running on Dos6.2 passes the protected mode test.

Should I consider it to be a bug/artifact of CheckIT1 and move past it... Or is CheckIT3 not testing the same thing?

Reply 1 of 1, by Grzyb

User metadata
Rank Oldbie

There's no HIMEM/EMM386 in DOS 3.30, so Checkit has to control the protected mode on its own.
I guess you're using DOS 6.20 with HIMEM (and maybe EMM386 as well), so Checkit makes use of them to access the protected mode.

Try running 6.20 with empty CONFIG.SYS and AUTOEXEC.BAT...

I think it's some incompatibility with Checkit, I also encountered similar problem with some machine, but forgot any details...
Anyway, if stuff like HIMEM, EMM386, Windows 3.x in Standard and Enhanced modes works fine, then there's nothing to worry about.