*BSD News Article 19474


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From: rkb55989@uxa.cso.uiuc.edu (Rafal Boni)
Newsgroups: comp.os.386bsd.questions
Subject: Re: Problems with NetBSD-08 and ESDI - Please help!
Date: 13 Aug 1993 17:16:11 GMT
Organization: University of Illinois at Urbana
Lines: 35
Message-ID: <24gi8r$g71@vixen.cso.uiuc.edu>
References: <244ule$cke@netbsd08.telecom.com.au> <BLYMN.93Aug11203209@mallee.awadi.com.au>
NNTP-Posting-Host: uxa.cso.uiuc.edu

blymn@awadi.com.au (Brett Lymn) writes:

>>>>>> On 9 Aug 1993 15:33:52 +0800, tdwyer@netbsd08.telecom.com.au (Terry Dwyer 491 5161) said:

>I tried replying via mail to this but I think your reply address (both
>with and without netbsd08 in it) are not correct.

>TD> off.  I have tried alternate sector mapping on and off, set the drive SPT
>TD> (according to manufacturers specs) to 34 and 36, used the ESDI bios to
>TD> low level format the drive, and WDFMT (a WD utility), to do the same.  
>TD> There is a difference in the way the formatters work - the BIOS utility
>TD> appears to replace every bad sector found with a sector it maps in from
>TD> the last two cylinders of the drive hence moving sectors to a different
>TD> rack on the disk.  The WDFMT util seems to mark the bad sectors (in place),
>TD> and leaves the drive geometry alone.  Needless to say, none of the above

>When I format my esdi (300Meg CDC with DTC controller) I select the
>"sector sparing" option which, from what I understand, allocates one
>sector per track as spare and will map this sector in if format finds
>a bad sector.  Sector sparing works well on a disk with few defects.
>After formatting with sector sparing I treat the disk as a defect free
>disk.
>--
>Brett Lymn

	A very defective disk LOSES big on sector sparing, however.  I have
	a 1007V with a 660MB drive that used to be in a corporate app. server
	and was taken out due to the increasing number of bad blocks/failures
	It works great for me [since I don't run 100 users off the system]
	but when I formateed it with sector sparing I lost ~20 MB off the drive.
	Now you may think 20 MB/660 isn't too bad... But when you have 3 OSes
	installed and the complete source for one of them... Things can get
	tight.

								Rafal