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Date: Thu, 25 Apr 2002 23:42:41 -0600
From: Erik Andersen <andersen@codepoet.org>
To: Bill Davidsen <davidsen@tmr.com>, Stephen Samuel <samuel@bcgreen.com>,
        linux-kernel@vger.kernel.org, Andre Hedrick <andre@linux-ide.org>
Subject: Re: A CD with errors (scratches etc.) blocks the whole system while reading damadged files
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On Thu Apr 25, 2002 at 09:04:57PM -0700, Mike Fedyk wrote:
> 1)
> Two drives each on a seperate cable, but on the same chipset:
> /dev/hda (hard drive) (chipset1)
> /dev/hdc (cd-rom) (chipset1)
> 
> Put broken CD into /dev/hdc, and read somehow (dd, cat, whatever), now try
> to read from /dev/hda.  This (according to this thread) should be damn slow
> and you will have a very hard time to use this system while it is trying to
> read the CD.

This has not been my experience.  Reading from hda continues to
work as expected.  But the process reading from hdc stays stuck
in D state for a _long_ time....  A kill -9 takes like 10 minutes
before it gets around to actually killing anything.

> 2)
> Two drives, each on a seperate cable and on different chipsets:
> /dev/hda (hard drive) (chipset1)
> /dev/hde (cd-rom) (chipset2)
> 
> Put broken CD into /dev/hde, read it again, and try to read from /dev/hda.
> All should be good, with blue skies, and a responsive system.

Sure.  Same as above.

> Also, can someone say for sure (Andre) that this is a hardware limitation,
> not a Linux IDE locking problem, and with no possibility of a software
> work-around? 

There is a certain amount of delay when a drive hits a bad
sector.  But Linux handles things pretty badly IMHO, and could 
do a much better job.

 -Erik

--
Erik B. Andersen             http://codepoet-consulting.com/
--This message was written using 73% post-consumer electrons--
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