DOS ain't dead

Strange quirk under v86-dsk acces under DOS 6.22 workaround (Users)

posted by RayeR , CZ, 31.12.2015, 21:32

After a discussion with Jack it become clear that the problem lies in BIOS DMA implementation. For some reason (probably a need to save space) the BIOS DMA support was simplified to not support v86 mode logic BUT only on two SATA3 ports. So the proper solution is to load xhdd driver before switching to v86 mode which takes DMA control over BIOS and prevent failure. In my case read mode still seems to work also in v86 mode so I load xhdd just after v86 memory manager.
Unfortunatelly there's no solution for Win9x as they don't like xhdd and there's no special SATA driver that will bypass the BIOS DMA logic. So as a workaround I moved Win98 to second HDD attached to SATA2 port and I use BIOS boot manager to swap boot drives, it works.

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DOS gives me freedom to unlimited HW access.

Complete thread:

• Strange quirk with JEMMEX 5.78 and disk acces under DOS 6.22 - RayeR, 29.12.2015, 19:25
  • Strnge quirk with JEMMEX 5.78 and disk acces under DOS 6.22 - Laaca, 30.12.2015, 08:09
    • Strange quirk with JEMMEX 5.78 and disk acces under DOS 6.22 - RayeR, 30.12.2015, 08:31
      • Strange quirk under v86-dsk acces under DOS 6.22 workaround - RayeR, 31.12.2015, 21:32
        • Strange quirk under v86-dsk acces under DOS 6.22 workaround - Laaca, 31.12.2015, 22:49