From owner-cvs-all  Tue Dec  7  0:51:44 1999
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Date: Tue, 7 Dec 1999 00:51:41 -0800 (PST)
From: Matthew Dillon <dillon@apollo.backplane.com>
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To: Mike Smith <msmith@FreeBSD.ORG>
Cc: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG
Subject: Re: cvs commit: src/sys/kern kern_shutdown.c 
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:
:>     The disk can lie about whether it has written data to the disk without
:>     messing softupdates up, but it cannot reorder writes that the system has
:>     told it must be ordered.  SCSI has a tag to guarentee ordering (or not),
:>     but I don't know if IDE has the same sort of feature.
:
:No, it doesn't.  I'm not entirely sure that SCSI disks will honour the 
:ordered tag all the way down to the media, either.  It wouldn't surprise 
:me very much to see it honoured only to the cache, with no guarantee that 
:a completed ordered tag guarantees on-media state.

    I am pretty sure SCSI disks honor the ordered tag, at least the big
    brands.

    IDE?  Who knows.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>


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