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From: gmreise@cs.vu.nl (Reisenstadt G M)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Flopy disk error handling
Summary: TrackSalve does all you want!
Message-ID: <6476@star.cs.vu.nl>
Date: 8 May 90 07:59:53 GMT
References: <5115@hub.ucsb.edu>
Sender: news@cs.vu.nl
Organization: Fac. Wiskunde & Informatica, VU, Amsterdam
Lines: 46


dougp@voodoo.ucsb.edu writes:

>In article <1410046@hpcvca.CV.HP.COM>, charles@hpcvca.CV.HP.COM (Charles Brown) writes...
>>> Handle floppies the way it is done now, untill you get an error. If
>>> you find an error on reading (the only time you can detect an error)
>>> go back and retry, but do the retry syncronous to index.
>> 
>>But by then you have already lost data.  My intention is that you
>>should never loose data.

>But a read is done immediatly after a write (otherwise you could never
>detect an error while writing), this is commonly known as verifing. Come
>to think of it, I don't know if the Amiga verifies the write or not.

The Amiga does not verify writes.

>It should at liest be an option for those willing to take a performance
>hit.

You need a program called 'TrackSalve' by Dirk Reisig (of PCopy fame). I
beleive he send an update (v1.3) to Fred Fish for inclusion in his library.

TrackSalve gives you the option to verify your writes on a per-drive basis,
so you could decide to have a 'save' and a 'fast' disk-drive if you have
more than one drive.
The new version even gives you something called 'MFM Update'. You'll have
to check the docs for that, but from memory I can tell that it has some-
thing to do with unused sectors in tracks becoming trashed after a while.


>If an error was detected on a verify read, the track could be rewritten
>in index syncronous mode, if it failed again, the block could be mapped
>out.

It does give you a requester with 'rewrite' or 'ignore'. If rewrite does
not work for some reason, you can save that file to another disk. I don't
think it does map blocks out (discussed a while back as to why not).

>>> 	Douglas Peale
>>	Charles Brown	charles@cv.hp.com or charles%hpcvca@hplabs.hp.com
>>			or hplabs!hpcvca!charles or "Hey you!"

>Douglas Peale

Marco Niese.     E-Mail: gmreise@cs.vu.nl  (Put: TO BMR in subject line.)