Date: Wed, 18 Aug 1999 22:17:12 -0500 From: David Kelly <dkelly@HiWAAY.net> To: "Kenneth D. Merry" <ken@kdm.org> Cc: clash@tasam.com (Joe Gleason), freebsd-scsi@FreeBSD.ORG Subject: Re: Defect Lists + camcontrol commands Message-ID: <199908190317.WAA76137@nospam.hiwaay.net> In-Reply-To: Message from "Kenneth D. Merry" <ken@kdm.org> of "Wed, 18 Aug 1999 10:51:03 MDT." <199908181651.KAA20599@panzer.kdm.org>
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"Kenneth D. Merry" writes: > > Is this a normal number of defects? > > It depends on how big your disk is. The best way to find out is to take a > survey of a bunch of disks of the same size. Find out the average number > of defects, and then you'll have a better idea of whether that's a lot of > defects. > > Presumably the factory quality control processes will spit out a disk with > too many defects, although you can't presume too much there. At my prior employment, I kept track of such things for every HD we had. I disagree with Kenneth's statement that the number of bad blocks varies with the size of the HD. It seemed to me that in early production of a particular size such as 4.3G 3.5" drives, the bad block rate was higher than the same model 6 months or a year later. New 4G HD's of a different model would also retain a low count factory bad block list. But then out would come 9G 3.5" disks and the bad block list grew again in early production, and fell on new drives 6 to 12 months later. For most any HD, 200 factory bad blocks was low. Nearly 1000 was not common, but not unheard of. Most all drives we had were Seagate. Then again there is always an exception. We had a 1G Conner HD that insisted it had no factory bad blocks. I don't believe it partly because when put to the test it grew 7. And partly because it was a crappy drive. > In general, you should be more concerned about increasing numbers of > defects on the grown defect list. Agreed. -- David Kelly N4HHE, dkelly@nospam.hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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