Arnaldo Ortega <[log in to unmask]> wrote:
> Hello guys:
>
> To begin my participation in this list, here is my question:
>
> System:
> - Pentium 166 MHz
> - 64 MB RAM EDO (2 x 32MB/72pin)
> - Adaptec AHA1542CF with Sony SDT4000E
> - NE2000 compatible
> - SB16 PnP
> - HD 6.4GB Western Digital IDE
> - CDROM 32X Creative
> No DMA or IRQ conflicts
>
> I used to have two 8MB/72pin memory cards in my computer for a long time
> and I changed it for two 32/72pin EDO recently. I also changed my HD
> from a DEC DSE2100 (2.1GB) and my CDROM unit, but I dont think it´s
> related to the problem.
>
> The problem is, before this changes the Adaptec BIOS test could run DMA
> test without problems and now it locks up the system at about memory
> address 90000h (right after the first 512k). I used to run Cheyenne
> Backup for Windows without any problems and now I´m trying to work with
> NT Backup. After some time backing up HD it stops telling the hardware
> reported an error. I´m really not sure if this is related to hardware or
> NT. More information: I got the BIOS test program from Adaptec (the DOS
> version) and it can run without problems, i.e. the board dma pass the
> test, if I boot from DOS with the BIOS disabled. I have also Linux
> instaled on the same system, and after some initial tests it seems to be
> ok. I´m going to do some more backup tests this weekend to ensure it
> runs ok from Linux. But the BIOS test is still failling.

The ISA bus has a DMA limitation of operating within only the first 16MB of
address space. There may be some workarounds, like looking for a BIOS setting of
"memory hole" or similar.

However, in newer systems that have more than 16MB of memory, you are better off
swapping it for a PCI controller which does not have this limitation.


--
Russ Poffenberger               Engineering Specialist
Schlumberger Technologies ATE   DOMAIN: [log in to unmask]
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