Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!bbn!uwmcsd1!uwmacc!rick
From: rick@uwmacc.UUCP (the absurdist)
Newsgroups: comp.sys.mac
Subject: Re: Followup to corrupted Excel file problem.
Message-ID: <2051@uwmacc.UUCP>
Date: Tue, 8-Dec-87 11:23:52 EST
Article-I.D.: uwmacc.2051
Posted: Tue Dec  8 11:23:52 1987
Date-Received: Sun, 13-Dec-87 11:42:34 EST
References: <6993@ut-ngp.UUCP>
Reply-To: rick@unix.macc.wisc.edu.UUCP (The Absurdist)
Organization: UW-Madison Academic Computer Center
Lines: 34

I recently had a user bring in "my only copy" of an Excel
file that could no longer be read.  A little work with
some disk utilities showed that the problem was that the first
sector had gone bad.  I made a sector copy of the disk, getting
a "legal" file that would start Excel.  However, Excel immediately
claimed that "This is not a saved Excel worksheet."

Microsoft refuses to document their file formats (boo!).
Lotus Corp. does (yeah!).  It occured to me that the two
were probably similar in intent, and that the Lotus 123
format keeps no real data in its header;  instead it has
all the settings for print ranges, graph types, etc.  So
I tried replacing the bad sector with the first sector of
a good Excel worksheet of similar size.  Voila!  All the
data came back.  I advised the person to PRINT OUT their
data, back the thing up, and then reset all their ranges.
As far as I know, that worked fine.

The Lotus 123 format is documented in a book by Lotus Corp.,
called "Lotus File Formats for 1-2-3, Symphony and Jazz."
It's published by Addison-Wesley.  Version 3 of Lotus
will have a revised file format, and they are going to
publish that one, too.  If you're really worried about
your data, keep it in .wks format, not Excel native format;
you can preserve just about all the worksheet settings,
and still decode it.  On the other hand, keeping a set
of BACKUPS together with a PAPER audit trail is better yet.
("No backup?  Well, can you can reconstruct the data from
the bills and receipts?" "Oh, no, we threw those all out."
"AAAAUGGGGHH!")

-- 
Rick Keir -- all the oysters have moved away -- UWisc - Madison
"Watch the skies...."