[net.unix-wizards] 4.1bsd vs. V80

dav@berkeley@csuf.UUCP (10/02/83)

4.1BSD does too use DMA to the versatec.  It just doesn't DMA from
user-space, but instead copies to kernel space a block at a time first
and then DMA's it from there.

			David L. Markowitz
			Rockwell International
			...!ucbvax!{ucivax,trw-unix}!csuf!dav

dmmartindale@watcgl.UUCP (Dave Martindale) (10/06/83)

The 4.1BSD Versatec driver DOES do its DMA from user space; it calls physio
to set things up for the transfer.  You may be confused by the "struct buf
rvpbuf" allocated in the driver; this is a buffer header used to contain
control info which is filled in by physio, not a data buffer.

	Dave Martindale