DOS ain't dead

Don't do this!!! 32bit pointers, GPFs and real mode (Developers)

posted by DOS386, 28.08.2010, 01:09

> The compatibility issue that I'm worried about is that it seems that a "dos
> boot disk" as prepared by later versions of windows

don't use such "DOS"

> boots into some sort
> of emm386-like mode where the switch to unreal mode fails because the CPU
> has already been set in some mode that breaks my "switch to unreal" code

Right But it breaks your "use of the unreal mode" too ...

> I've never really investigated what that problem is

V86 has the 64 KiB segment limit too and you can't do INC CR0 in V86 mode ...

> "switch from pmode to real mode" before switching to unreal mode might fix

YES, but "V86 to real" is difficult and depends from EMM386 version, there is no good official way ...

> it may be gone. One week ago today I suffered a HDD+motherboard+power
> supply failure

Voltage increase killed all the other stuff ???

> and lost everything. I have backups of all my good stuff,
> but I suspect that that update might have been tucked away in an unbacked
> up folder since it was just to test. IIRC, it was an easy change to make
> (just the device+vendor ID) so I can do it again once I get a new machine.

---
This is a LOGITECH mouse driver, but some software expect here
the following string:*** This is Copyright 1983 Microsoft ***

Complete thread:

• 32bit pointers, GPFs and real mode - DOSferatu, 27.08.2010, 00:57 (Developers)
  • Don't do this!!! 32bit pointers, GPFs and real mode - DOS386, 27.08.2010, 03:04
    • Don't do this!!! 32bit pointers, GPFs and real mode - DOSferatu, 27.08.2010, 19:27
      • Don't do this!!! 32bit pointers, GPFs and real mode - DOS386, 28.08.2010, 01:09
  • 32bit pointers, GPFs and real mode - bretjohn, 29.08.2010, 17:59