Adaptec AHA1542 SCSI controller & h

[Karl Denninger]

Thanks Roy.

A few months back I saw some patches to change the DMA rate (bus speed) on
the AHA 154x cards for 386/ix.  I didn't save it, unfortunately.

Now, with the new version of the SCSICNTL.EXE program, I've managed to
enable read-ahead cache.  It's obvious from the lights that the drive is
faster than the bus is running at the moment (the green drive LED goes off
while the bus activity light is still on at times :-).  

I have checked out the controller/system combination up to 8Mhz.  It works
great.  386/ix, however, appears to >ignore< the jumpers on the controller
(grrrr...)... thus the need for the patch.

If someone has it, I would appreciate the particulars.  

Thanks!

(Ps: Is it unusual for systems to work at 8Mhz DMA rates?  Our 20Mhz systems
     do just fine even at full speed..... although the 25 cache boards we 
     have tried ALL fail with the cache enabled!)

Email or a pointer to the info appreciated.

--
Karl Denninger (karl at ddsw1.MCS.COM, <well-connected>!ddsw1!karl)
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