*BSD News Article 86785


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From: cjs@cynic.portal.ca (Curt Sampson)
Newsgroups: comp.os.linux.misc,comp.os.linux.setup,comp.unix.bsd.bsdi.misc,comp.unix.bsd.misc
Subject: Re: IDE vs SCSI (was Re: Linux vs BSD)
Date: 23 Jan 1997 12:46:09 -0800
Organization: Internet Portal Services, Inc.
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Message-ID: <5c8imh$4b8@cynic.portal.ca>
References: <32DFFEAB.7704@usa.net> <5c155c$p6u@raven.eva.net> <87k9p4rckd.fsf_-_@murkwood.gaffaneys.com> <5c8a39$7tn@usenet.srv.cis.pitt.edu>
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Xref: euryale.cc.adfa.oz.au comp.os.linux.misc:152437 comp.os.linux.setup:92244 comp.unix.bsd.bsdi.misc:5603 comp.unix.bsd.misc:1916

In article <5c8a39$7tn@usenet.srv.cis.pitt.edu>,
Mark Hahn <hahn@neurocog.lrdc.pitt.edu> wrote:

>where tagged queueing would give SCSI an advantage is those
>places where naive elevator sorting (by block number) doesn't work:
>lower-numbered blocks within the current cylinder and bad-block
>remapping.

Actually, it should give an advantage in latency on busy drives;
the drive, after transferring data to the controller, does not have
to wait to receive a new command before starting its next seek. In
fact, on drives with a reasonably large buffer cache, the drive
could start the next seek even before transferring the data read
after the seek to the host controller.

cjs
-- 
Curt Sampson    cjs@portal.ca		Info at http://www.portal.ca/
Internet Portal Services, Inc.	
Vancouver, BC   (604) 257-9400		De gustibus, aut bene aut nihil.