[comp.unix.i386] Can a NCR PC916 handle first party DMA

soc@dr.uucp (Steinar O. Cook) (06/12/90)

I'm having a lot of trouble with running Adaptech SCSI controlers
on my NCR PC916 with ISC 2.0.2. The errors indicates that the machine
does not support "firs party DMA" whatever that might be. Can anyone 
confirm if the NCR PC916 supports "first party DMA" ?

root@maxed (0000-Admin(0000)) (06/13/90)

In article <656@dr.uucp> soc@dr.uucp (Steinar O. Cook) writes:
>I'm having a lot of trouble with running Adaptech SCSI controlers
>on my NCR PC916 with ISC 2.0.2. The errors indicates that the machine
>does not support "firs party DMA" whatever that might be. Can anyone 
>confirm if the NCR PC916 supports "first party DMA" ?

You can run the onboard DMA test: Boot up under DOS and run debug
with the command at debug's - prompt: g c800:9 or g dc00:9 or whatever
you have the ROM address set to, and the DMA test will run.


-- 
 Ed Whittemore 		uunet!maxed!ed
 American Micro Group 		201 944 3293

als@bohra.cpg.oz (Anthony Shipman) (06/27/90)

In article <327@ke4zv.UUCP>, gary@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@bohra.cpg.oz.au
Computer Power Group
9th Flr, 616 St. Kilda Rd.,
St. Kilda, Melbourne, Australia
D