DOS ain't dead

INT 15.87 in protected mode (Developers)

posted by ecm  , Düsseldorf, Germany, 01.09.2011, 02:17

> > If the DPMI host runs as VCPI client, it will switch "back" to v86-mode
> > (hopefully using the VCPI API ), because anything else will cause
> > disaster. I don't think that cwsdpmi or hdpmi differ in this regard.
>
> I don't know the details. I got the impression that, overall, switching to
> V86 mode is preferable for speed and other reasons. But, IIRC, CWSDPMI
> doesn't do that in all cases, and usually only switches to real mode.

No, that's not possible. As Japheth pointed out, a DPMI host running as VCPI client needs to switch to V86, it mustn't switch to RM instead. (A DPMI host running stand-alone (from RM and without VCPI) could switch either to RM or to V86, but in the latter case it would need to set up and manage the V86 environment itself.)

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l

Complete thread:

• INT 15.87 in protected mode - Laaca, 29.08.2011, 14:11 (Developers)
  • INT 15.87 in protected mode - Rugxulo, 29.08.2011, 23:28
    • INT 15.87 in protected mode - Japheth, 30.08.2011, 05:27
      • INT 15.87 in protected mode - Rugxulo, 30.08.2011, 05:37
      • INT 15.87 in protected mode - Laaca, 30.08.2011, 07:22
        • INT 15.87 in protected mode - Japheth, 30.08.2011, 08:47
          • INT 15.87 in protected mode - Rugxulo, 31.08.2011, 01:30
            • INT 15.87 in protected mode - Laaca, 31.08.2011, 07:33
              • INT 15.87 in protected mode - Rugxulo, 31.08.2011, 21:27
                • INT 15.87 in protected mode - Laaca, 02.09.2011, 07:10
                  • INT 15.87 in protected mode - marcov, 02.09.2011, 09:58
                    • INT 15.87 in protected mode - Rugxulo, 03.09.2011, 21:49
                      • INT 15.87 in protected mode - DOS386, 04.09.2011, 12:43
            • INT 15.87 in protected mode - Japheth, 31.08.2011, 10:11
              • INT 15.87 in protected mode - Rugxulo, 31.08.2011, 21:25
                • INT 15.87 in protected mode - ecm, 01.09.2011, 02:17
                  • INT 15.87 in protected mode - Rugxulo, 01.09.2011, 04:31
                    • INT 15.87 in protected mode - Rugxulo, 01.09.2011, 05:00
  • INT 15.87 in protected mode - RayeR, 07.09.2011, 10:28
    • INT 15.87 in protected mode - Laaca, 07.09.2011, 12:28
      • INT 15.87 in protected mode - RayeR, 07.09.2011, 21:05
        • INT 15.87 in protected mode - Laaca, 08.09.2011, 07:33
          • INT 15.87 in protected mode - bretjohn, 08.09.2011, 18:19
            • INT 15.87 in protected mode - Laaca, 08.09.2011, 22:39
              • INT 15.87 in protected mode - Rugxulo, 08.09.2011, 22:50
          • INT 15.87 in protected mode - RayeR, 08.09.2011, 22:27
            • INT 15.87 in protected mode - bretjohn, 09.09.2011, 00:31
              • INT 15.87 in protected mode - RayeR, 09.09.2011, 01:51
                • INT 15.87 in protected mode - bretjohn, 09.09.2011, 20:09
                • INT 15.87 in protected mode - bretjohn, 09.09.2011, 23:17