question about DMA devices

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Article #11204

#11204

From: David Kotz
Date: Fri, 18 Dec 1992 16:59

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I have a question about DMA devices, specifically for networks and disks.

Do you know if it is possible (and if so, common) for a DMA device to
support scatter/gather? In particular, I'm trying to model a
multiprocessor interconnect network interface, and it would be very
helpful if I could avoid packetization by specifying the addresses and
lengths of my message header and message body, for the network DMA to
pick up. I'm guessing that this is not usually an option.

Also, in a disk interface, can it read in a whole track but scatter
the blocks to different locations in memory? I'm guessing that this
kind of thing is more common.

Thanks,
dave
-- 
-----------------
Mathematics and Computer Science
Dartmouth College, 6188 Bradley Hall, Hanover NH 03755-3551
email: David.Kotz@Dartmouth.edu    or   dfk@cs.dartmouth.edu

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Newsgroups: comp.arch,comp.parallel
Path: arc1-ca.pugleaf.net!sparky!uunet!usc!cs.utexas.edu!sdd.hp.com!ncr-sd!ncrcae!hubcap!fpst
From: dfk@wildcat.dartmouth.edu (David Kotz)
Subject: question about DMA devices
Message-ID: <1992Dec18.175402.27841@hubcap.clemson.edu>
Apparently-To: comp-parallel@rutgers.edu
Followup-To: comp.arch
Summary: can they do scatter/gather?
Originator: dfk@wildcat.dartmouth.edu
Keywords: DMA, scatter/gather
Sender: news@dartmouth.edu (The News Manager)
Organization: Dartmouth College, Hanover, NH
Date: Fri, 18 Dec 1992 16:59:15 GMT
Approved: parallel@hubcap.clemson.edu
Lines: 21