DMACHK
------


DMACHK checks each 16KB block beween C000 and EFFF
if it's writable and if it is, if ISA DMA transfers
work.


DMACHK is made to check the capability of ISA DMA transfers
within UMBs created by UMBPCI. Because UMBPCI creates UMBs
from RAM that is intended as shadow RAM, ISA DMA doesn't
work on some chipsets. 

If ISA DMA doesn't work, especially floppy accesses will
not work. So, you should not load high SMARTDRV.
And you should not use UMBPCI on a bootdisk!



Start it in pure DOS. UMBPCI should be loaded either from
CONFIG.SYS or from commandline using CTLOAD.EXE.



Example:

On a Intel 440BX chipset without any extra BIOS blocks (USB, SCSI or whatever)
and with VGA card using a 32KB VGA-BIOS it looks so:

ISA-DMA-Checker for UMBPCI V1.12, (c)1999-2000 by Heiko Nocon, Uwe Sieber 
http://www.uwe-sieber.de

 North-Bridge:  Vendor: 8086  Device: 7190
 South-Bridge:  Vendor: 8086  Device: 7110

C000-C3FF : write protected
C400-C7FF : write protected
C800-CBFF : read/write ok, ISA-DMA failed
CC00-CFFF : read/write ok, ISA-DMA failed
D000-D3FF : read/write ok, ISA-DMA failed
D400-D7FF : read/write ok, ISA-DMA failed
D800-DBFF : read/write ok, ISA-DMA failed
DC00-DFFF : read/write ok, ISA-DMA failed
E000-E3FF : read/write ok, ISA-DMA ok
E400-E7FF : read/write ok, ISA-DMA ok
E800-EBFF : read/write ok, ISA-DMA ok
EC00-EFFF : read/write ok, ISA-DMA ok


This means that on the i440BX ISA DMA works at E000-EFFF only.

Conclusion: 

On a bootdisk use the /I parameter to make UMBPCI uses 
E000-EFFF only:

device=c:\umbpci\umbpci.sys /i=e000-efff







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