*BSD News Article 5740


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Newsgroups: comp.unix.bsd
Path: sserve!manuel!munnari.oz.au!uunet!spool.mu.edu!think.com!rpi!psinntp!psinntp!ficc!peter
From: peter@ferranti.com (peter da silva)
Subject: Re: 386BSD and IDE drives
Message-ID: <id.O7NT.0O3@ferranti.com>
Organization: Xenix Support, FICC
References: <19r0h6INNp42@aludra.usc.edu> <1992Sep24.022400.19483@fcom.cc.utah.edu> <Bv32LD.K9t@chinet.chi.il.us>
Date: Mon, 28 Sep 1992 21:20:26 GMT
Lines: 38

In article <Bv32LD.K9t@chinet.chi.il.us> randy@chinet.chi.il.us (Randy Suess) writes:
> 	Something is very wrong here.  My experience is that IDE drives
> 	are great for UNIX and IDEAL for 386bsd.  Main reason is that, like
> 	SCSI, they hide bad sectors from the OS.

This is the one problem with SCSI, and presumably IDE. Why? What happens
when you have a marginal disk? When you're running MFM or ESDI, you start
getting more and more disk errors, and you have time to back up and reformat.
When you're running SCSI, you suddenly (without warning) get a LOT of errors
when the bad sector table fills up. By then it's too late to do anything
about it.

I've been burned by this.

I used to think this sort of bad track mapping was cool, but I've come to the
conclusion that the operating system should manage bad sectors. It's the part
of the whole system that knows (1) what the bad sectors mean, and (2) how to
tell the user something's wrong.

Of course, it needs to do a good job of this, with options to automatically
map bad blocks into a bad block list and tools to clean up afterwards. This
is a lot harder than assuming a perfect medium. But it's 

>       Never a need to run bad144 or worry about bad sectors.

Oh, you should worry. Trust me.

>       Second, for a 1 or 2 drive system, IDE
> 	is a non-negligable amount less cost than SCSI.

Not unless you really compromise on the quality of the drives, or unless
you've got some sort of special deal. Street prices vary by $20-$50 for
the same drive in SCSI and IDE versions.
-- 
Peter da Silva                                               `-_-'
Ferranti Intl. Ctls. Corp.                                    'U` 
Sugar Land, TX  77487-5012
+1 713 274 5180                                   Har du kramat din varg idag?