DOS ain't dead

XDMA32/XCDROM32 VirtualPC and VirtualBox issues (Emulation)

posted by Japheth , Germany (South), 11.12.2007, 11:31
(edited by Japheth on 11.12.2007, 11:45)

VirtualBox is based on Qemu. It uses a different BIOS which apparently hasn't Qemu's problem and allows to find the UDMA IDE controller without using XDMA32/XCDROM32's /P option. However, there's a problem with DMA in VirtualBox v1.52. I could only run XDMA32 reliable when using the new /B switch, which causes all reads to use the XMS buffer. Speed boost is still significant, fortunately (> 200%). Sample:

DEVICE=C:\JLOAD.EXE XDMA32.DLL /B


MS's VirtualPC 2007 is also somewhat strange. It's IDE controller supports DMA, but not UDMA. Therefore, to use XDMA32 and XCDROM32, one has to use the new /W switch, which allows the drivers to accept devices capable of "Multiword"-DMA only. For XDMA32, the speed increase is not significant (about 10%-15%), but using XCDROM32 with /W option boosts speed more than 100%. Sample:

DEVICE=C:\JLOAD.EXE XCDROM32.DLL /W

(use the drivers found in XJLM.ZIP)

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MS-DOS forever!

Complete thread:

• More Speed with QEMU and XDMA32/XCDROM32 - Japheth, 09.12.2007, 13:07 (Emulation)
  • Jack's comments - Khusraw, 09.12.2007, 21:05
    • Jack's comments - Steve, 10.12.2007, 08:26
    • Jack's comments - Japheth, 10.12.2007, 09:11
  • More Speed with QEMU and XDMA32/XCDROM32 - Rugxulo, 10.12.2007, 23:59
    • License (non-)issues again - Japheth, 11.12.2007, 15:18
      • More Speed with QEMU and XDMA32/XCDROM32 - rr, 11.12.2007, 15:30
        • More Speed with QEMU and XDMA32/XCDROM32 - Japheth, 11.12.2007, 16:21
          • More Speed with QEMU and XDMA32/XCDROM32 - rr, 11.12.2007, 17:23
            • More Speed with QEMU and XDMA32/XCDROM32 - sol, 11.12.2007, 17:44
            • More Speed with QEMU and XDMA32/XCDROM32 - Japheth, 11.12.2007, 22:57
      • License (non-)issues again - Rugxulo, 11.12.2007, 18:11
  • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - Japheth, 11.12.2007, 11:31
    • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - rr, 11.12.2007, 11:48
      • Bochs problems - Japheth, 11.12.2007, 12:05
        • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - rr, 11.12.2007, 13:15
          • Bochs v2.35 regression - Japheth, 11.12.2007, 14:03
            • Bochs v2.35 regression - rr, 11.12.2007, 14:41
              • Bochs v2.35 regression - Japheth, 11.12.2007, 14:58
                • Bochs v2.35 regression - rr, 11.12.2007, 15:31
      • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - sol, 11.12.2007, 17:22
        • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - rr, 11.12.2007, 17:24
    • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - tom, 12.12.2007, 14:43
      • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - rr, 12.12.2007, 16:42
      • Virtual Machine detection... - Rugxulo, 12.12.2007, 17:08
      • XDMA32/XCDROM32 VirtualPC and VirtualBox issues - Japheth, 12.12.2007, 17:29