Path: utzoo!utgpu!water!watmath!clyde!att-cb!osu-cis!tut.cis.ohio-state.edu!mailrus!umix!uunet!mcvax!ukc!mupsy!liv-cs!sqrkl
From: sqrkl@csvax.liv.ac.uk
Newsgroups: comp.sys.mac
Subject: I fixed an unreadable floppy...now you can too !
Message-ID: <487@csvax.liv.ac.uk>
Date: 15 Apr 88 11:50:26 GMT
Lines: 40
Organisation: Computer Science CSVAX (VAX1), Liverpool University

Ever had a disk go 'unreadable' on you ? Well, read on...

My MacWrite disk decided to self-destruct the other day...so badly that the
Finder kept saying that the 'disk is unreadable' !! Having plenty of work on
it, I set myself the task of fixing it.
   I first tried 'DiskExpress' which provides a Finder-like interface for
compressing/verifying/repairing disks. Unfortunately, it was TOO much like the
Finder - it claimed the disk was unreadable as well (with a remarkably similar
dialog box, I might add).
   Next, I tried 'Fedit+'. I really like this program - it's great for just
hacking around, so I was quite optimistic about my chances. At least it recog-
nised the faulty disk (it just called it 'External Drive'), so I did an 'Open
Volume' on it and -BINGO- up came sector 0 of the disk. Simple investigation
found that absolute sectors 3 and 4 were unreadable, but Fedit+ wouldn't show
me sectors 3 or 4 (it stuck on sector 2 if I used Next Sector and sector 5 if
I tried Prev Sector). So I resorted to the good old 'Read Multiple Sectors' and
'Write Multiple Sectors' with buffer 0, from sector 3 and length 2 sectors.
I used 'Read Mult...', ignored the error dialog, then 'Write Mult...'. Hooray !
I now had readable sectors 3 and 4, but...they had rubbish in them.
   It now dawned on me that Fedit+ had no 'Repair boot tracks/directory
structure' option, but DiskExpress DID. So I trundled back to DiskExpress,
where I got 'Disk is damaged' instead. However, DiskExpress bestowed pity on
me and this time let me mount the disk and do things with it. So I set the
'Repair Automatically' flag on and clicked on 'Start', then prayed...
   My prayers were answered. On exiting to the Finder, ejecting the suspect
disk (Shift-Command-2) and re-inserting it mounted a pefect working copy of
MacWrite. One disk backup later and I had a good disk again.
   So the moral of this tail is - Don't Give Up (unless you're Kate Bush or
Peter Gabriel !) on bad disks : they can be salvaged with some patience and
copies of Fedit+ and DiskExpress.

Richard K. Lloyd,          ***************************************************
Computer Science Dept.,    * JANET : SQRKL@UK.AC.LIV.CSVAX                   *
Liverpool University,      * UUCP  : {backbone}!mcvax!ukc!mupsy!liv-cs!SQRKL *
Merseyside, England,       * ARPA  : SQRKL%csvax.liv.ac.uk@nss.cs.ucl.ac.uk  *
Great (?) Britain.         ***************************************************

"I have VERY strong opinions which are nothing whatsoever to do with the
University of Liverpool, so blame ME if I bitch about useless IBM PC clones,
even more redundant IBM mainframes and the terrible Atari ST..."