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From: pjm@cdromshop.com (Peter-John Maxwell)
Newsgroups: comp.unix.bsd.bsdi.misc
Subject: Re: SCSI drive settings question
Date: Wed, 13 Mar 1996 02:32:07 -0500
Organization: The CD-ROM Shop
Lines: 31
Message-ID: <pjm-1303960232070001@pjm.interlog.com>
References: <4hna0a$19q@stout.entertain.com>
NNTP-Posting-Host: pjm.interlog.com
In article <4hna0a$19q@stout.entertain.com>, dwatson@stout.entertain.com
(Darryl Watson) wrote:
> What effect does enabling the 'parity check' function on SCSI drives?
> Can the drive or disk subsystem automagically map out bad sectors if
> parity is enabled? Or is it a situation where if there is a write error,
> enabling parity checks will cause the system to panic more often?
Personally I would never contemplate turning parity checking off.
When a parity error occurs, that track/sector is mapped out at the
drive level without the controller even being aware of it.
Basically the situation looks like this:
an 8 bit byte:10101010 parity bit 0
If any bit changes ie:
10101011 with the parity still at 0,
You know that an error has occured in the storage of this byte.
The drive will map any track/sectors where the errors occur to
a "hidden" track/sector outside of the normally useable space on
the HD.
Hope this helps,
PJ
> Any information in this regard is appreciated!
--
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