Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site utastro.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!ut-sally!utastro!nather
From: nather@utastro.UUCP (Ed Nather)
Newsgroups: net.micro.pc
Subject: Re: Norton utilities question
Message-ID: <343@utastro.UUCP>
Date: Fri, 12-Jul-85 14:25:53 EDT
Article-I.D.: utastro.343
Posted: Fri Jul 12 14:25:53 1985
Date-Received: Tue, 16-Jul-85 03:40:19 EDT
References: <5507@tekecs.UUCP>
Distribution: net
Organization: U. Texas, Astronomy, Austin, TX
Lines: 27

> One of the Norton utilities claims to be able to recover
> deleted files.  Does it actually do this?  If so, how?
> Can anyone share experiences with actually recovering files?
> 
> 	Glen McCluskey
> 	..tektronix!tekecs!glenm

When you ask MS-DOS to delete a file it marks the first byte of the file
with a code that means "available for use as new storage" but otherwise
leaves it alone.  The Norton utility examines all files for that code,
and displays the original filename except for substituting "?" for the
first byte, and asks you if you want to try to salvage it.  If you do,
and the file is still intact, it can be restored.

Note, however, that a deleted file has become a prime candidate for
being overwritten; if you delete a file and then write to that disk, it
is very likely the old file will be overwritten, and thus be sent to
Byte Heaven.  I understand DOS 3 is smarter about this than DOS 2, which
finds joy in overwriting as soon as it can.  DOS 3 waits until all other
storage is exhausted before reclaiming file space from deletions, so you
have a better chance -- but no guarantee -- of successful restoration.

-- 
Ed Nather
Astronomy Dept, U of Texas @ Austin
{allegra,ihnp4}!{noao,ut-sally}!utastro!nather
nather%utastro.UTEXAS@ut-sally.ARPA