Subject: Re: NCR Driver Problems
To: None <,>
From: proprietor - Foo Bar And Grill <>
List: current-users
Date: 01/31/1996 15:34:55

 * It's the drivers.  Hacking FFS won't do jack.

[That's what I asked.  Thanks...]

 * In general, using queue tagging can only help performance (unless
 * you're doing something dumb like trying to use too many tags; the
 * number of tags supported is a drive-dependent value).  If you consider
 * the worst case of a drive's handling of tagged commands, it will
 * process them in the order received.  That's equivalent to sending them
 * down one at a time.  (OK, actually, if you send them down one at a
 * time, the extra delay in sending them to the drive may get you some
 * disksort() wins, but it's not clear that it would really help.)  In
 * the best case, the drive can optimize the handling of the requests so
 * that they're handled in the 'best' order.

So, in other words, disksort() is now obsolete and should be replaced.

Are there any drives newer than, say, two years old which don't handle

Should not the SCSI driver attempt to determine whether or not the drive
handles tagging, and disable tagging for that drive if tagging fails?

 * chris

#undef AUTHOR	/* "Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU (Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU)" */

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