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Path: utzoo!utgpu!water!watmath!clyde!burl!codas!killer!richardh
From: richardh@killer.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: UNIX
Message-ID: <1610@killer.UUCP>
Date: Wed, 23-Sep-87 19:19:45 EDT
Article-I.D.: killer.1610
Posted: Wed Sep 23 19:19:45 1987
Date-Received: Sat, 26-Sep-87 10:02:26 EDT
References: <174@westmark.UUCP-> <1822@watcgl.waterloo.edu>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 20
Summary: MS-DOS filesystem fragility

In article <1822@watcgl.waterloo.edu>, smvorkoetter@watmum.waterloo.edu (Stefan M. Vorkoetter) writes:
> 
> MS-DOS uses write through buffers.  When you read a sector, it will check
> if the sector is in a buffer, and read it from there if it is.  When you
> write a sector, it writes straight to the disk (AND the buffer).  The file
> will only be trashed if a crash occurs during the write.
> 
> Stefan Vorkoetter
> University of Waterloo

The file will be trashed if the write puts data past the current end of file
and the file is not closed. It is only on close that the directory entry for
the file is updated. This doesn't require a system crash. A ^C abort or a
crtical DOS error (those famous words "Abort, Retry, Ignore ?") can cause a
file being written-to to lose some of its data.  

regards,
richard hargrove
...!ihnp4!killer!richardh
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