[comp.sys.apple2] DMA SCSI problem

gwyn@smoke.BRL.MIL (Doug Gwyn) (07/26/90)

In article <43316@apple.Apple.COM> dlyons@Apple.COM (David A. Lyons) writes:
>(By the way, has anybody else had trouble using the high-speed SCSI card
>after installing the special OS and drivers that come with it, over your
>existing 5.0.2 installation?  My system was hanging about 2/3 of the way
>through my boot, apparently in the middle of a SCSI read.  I solved the
>problem temporarily by turning off the DMA switch on the card, but that
>shouldn't be necessary--I don't have a large memory card or any other DMA
>peripherals in that particular system.)

The point at which the boot was "hanging" corresponds to the place I had
problems when I had a DMA-incompatible memory card configuration (2MB
OctoRAM using 256K SIMMs); I think that's the first spot where the GS/OS
(potentially DMA) driver is used instead of slot firmware.  If you have a
TWGS it needs a PAL upgrade in order to work with the new SCSI card in
DMA mode.

dlyons@APPLE.COM (David A. Lyons) (07/26/90)

Unfortunately, I have no TWGS in my system either...my hang remains a
mystery for now.