Can a NCR PC916 handle first party DMA (SCSI problems) ?

[Anthony Shipman]

In article <327 at ke4zv.UUCP>, gary at ke4zv.UUCP (Gary Coffman) writes:
> motherboard with 8Meg of ram, the AHA1542, a MDA, and two serial cards. 
> I am running ISC 2.02 Unix and the drives are a ST296N and a Micropolis
> 1578. System lockups occur only on the 1578 and only under heavy disk
> access such as running compress on a large file. Running compress on
> the same file on the ST296N works flawlessly. I have run all the 
> diagnostics at my disposal and none report any problems. I have tried
> operating with the cache disabled, the bus speed set at 8 Mhz, at 11.33
> Mhz, etc and the system still hangs when hit with heavy disk loading of
> the 1578. This sounds to me like a 1578 problem, yet everyone tells me
> that the 1578 is compatible with the AHA1542. Are there some magic

I have seen the same symptoms on an NEC 386/20 machine with an ESDI controller,
two 140MB drives and running 2.0.2. The lockup occurred when trying to access 
a second drive. It seemed to be load dependent with a rather low threshold.
-- 
Anthony Shipman                               ACSnet: als at bohra.cpg.oz.au
Computer Power Group
9th Flr, 616 St. Kilda Rd.,
St. Kilda, Melbourne, Australia
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