From owner-cvs-all  Mon Oct 12 12:27:59 1998
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Date: Mon, 12 Oct 1998 12:27:30 -0700 (PDT)
From: Matthew Dillon <dillon@apollo.backplane.com>
Message-Id: <199810121927.MAA16373@apollo.backplane.com>
To: Mike Smith <mike@smith.net.au>
Cc: "Kenneth D. Merry" <ken@plutotech.com>, mike@smith.net.au (Mike Smith),
        cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG
Subject: Re: cvs commit: src/sys/cam/scsi scsi_da.c 
References:  <199810121913.MAA07536@dingo.cdrom.com>
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    cache-sync is such a fundamental command, I can't imagine any drive
    not doing the right thing with it, especially drives which support tagged
    commands.  The command is tightly integrated into the disk cache paradigm
    as given by the SCSI-II standard.

    But I guess there could be a few...  even so, I think we have to support
    it.  It's just too important a command, especially in larger RAID SCSI 
    systems which have huge write caches.  Consider a UPS signalling a machine 
    that it's about to die and the machine trying to flush everything out and 
    shut down.  Better to get the cache flushed to disk (non-volatile or not) 
    before power goes poof.

    Have there been any specific reports of problems with the use of
    the command other then the vague micropolis report in the first
    email (first email that I got, anyway) ?

						-Matt

    Matthew Dillon  Engineering, HiWay Technologies, Inc. & BEST Internet 
                    Communications & God knows what else.
    <dillon@backplane.com> (Please include original email in any response)    


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