Help on System V/AT DMA needed

[David A. Bright]

I have been trying to write a device driver for a tape drive under System V/AT,
but can't seem to get DMA to work.  When I initiate data transfer, it doesn't
seem to work (I get an error indication from the tape drive); sometimes the
residual count is non-zero, sometimes it isn't.  I don't know exactly what is
the problem (from the drive's perspective), because to get extended status, I
need to do DMA (Catch-22!).  The documentation from Microport on writing device
drivers is, to say the least, sketchy.  Any help would be greatly appreciated.

--
David A. Bright
910 W. Burke Avenue		dab at Bright.MN.ORG	(Home)
Roseville, MN  55113		
612 487-2407 (Voice)		612 487-2416 (Data)

-- 
David A. Bright
910 W. Burke Avenue		dab at Bright.MN.ORG	(Home)
Roseville, MN  55113		
612 487-2407 (Voice)		612 487-2416 (Data)