On Jun  4, 11:46am, Toru Nishimura wrote:
> Hi, all.
> 
> > The PMAZ-A card gets it clock from the TurboChannel clock.  [I've
> > measured the clock input on the 53C94 on several different
> > configurations to verify the 53C94 clock configuration was getting set
> > correctly.] 
> 
> Ok, I see.  The question now is how reliably PMAZ-A can run at 25MHz
> NCR53C94 chip clock rate (in driver's sense) attached with 3MIN and
> MAXINE.  I will wait for field reports. 

  I doubt there's any problem with reliablity.  I can think of only two
things this would affect.  One is that a section timeout would be 500ms
instead of 250ms.  This will exceed the SCSI specs, but shouldn't hurt
anything.  The other timing that would be affected would be the
synchronous transfer rate.  Data sent from the 53C94 would be sent at
1/2 the expected rate.  Most, if not all, targets devices shouldn't
be bothered by that - it just means the data would be transferred
half as fast.

  I suppose I should drag out my oscilloscope, move my external
drives to the PMAZ-A card and measure the actual data rate of
writes to the disk.

  The timing could also be checked by seeing how long the device
probes take for the PMAZ-A card with no devices.

-- 
Michael L. Hitch			mhitch@montana.edu
Computer Consultant
Information Technology Center
Montana State University	Bozeman, MT	USA