gnd@tetons.UUCP (Greg Darnell) (09/30/88)
A week ago I decided to take the plunge and upgrade my low-budget
XT clone to an AT. I bought the 6/8/10/12 MHz JE1007 board from Jameco
when they dropped the price, plugged it in and everything worked fine.
Then I decided to run some benchmarks for fun, such as PC Magazine's
and the Corefast test, and found that the hard disk transfer rate had
dropped from 180 KBytes/sec to 25 KB/sec.
The disk is a standard ST225 with a controller with WD markings but
an Everex ROM in it. I know an 8-bit controller is not really enough
for an AT but I would like it to at least work as fast as it did in the
XT until I can afford a new controller. The bus speeds in both the XT
and AT were 8MHz, the data on the disk was unchanged, so why such a
massive drop in transfer rate? Seek times stayed unchanged. I had to
tell the AWARD BIOS that no hard disks were installed since it can't
seem to talk to my controller (just as Jameco's manual predicted).
A friend suggested that in its new environment the interleave on the
disk might be wrong. I tried changing the interleave to what appeared
to be optimal and got the rate up to 58 KBytes/sec using the same test.
Apparently that was not the major problem.
My main theory now is that DMA is not working, perhaps because the
BIOS sets up DMA channels based on the CMOS configuration and thus has
not enabled a channel for this hard disk???? The motherboard is not at
fault, because I plugged the controller/disk into a Compaq 286 at work
and got the identical symptoms.
Another possibility is that the controller card is incorrectly set,
but I tried almost every combination of jumpers (I didn't get any docs
with the card) and nothing changed.
Has anyone seen this problem before? What is going on????
Please email responses as I don't get to read this newsgroup often.
Greg
--
Greg Darnell Amdahl Corporation 143 N. 2 E., Rexburg, Idaho 83440
UUCP:{ames,decwrl,sun,uunet}!amdahl!tetons!gnd (208) 356-8915
INTERNET: gnd@tetons.idaho.amdahl.com