Unique file determination

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#1837

From: Michael Rice
Date: Thu, 09 Aug 1990 19:39

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What I want to do is store some type of file indentifier for each file
so when I get a new file I can create this identified and check it
against the identifiers for my other files.  If they match then I would
know that file is a duplicate.  

They way I implemented this (the first thing that came into
my mind) was to add up the first X number of bytes and use this
as the indentified (checksum?).  When this X is about 1000 bytes
I found 5 duplicates that were duplicates and 1 set that were not
duplicates. This was with about 100 files.

Any ideas on a better way to do this, more accurate, etc?
I am doing this in Turbo C if that matters.
Any help is appreciated.
Mike

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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!samsung!uakari.primate.wisc.edu!caen!willow.engin.umich.edu!mrice
From: mrice@caen.engin.umich.edu (Michael Rice)
Newsgroups: comp.os.msdos.programmer
Subject: Unique file determination
Summary: How do I determine if two files are the same?
Keywords: Turbo C Checksums
Message-ID: <1990Aug9.193919.2996@caen.engin.umich.edu>
Date: 9 Aug 90 19:39:19 GMT
Sender: news@caen.engin.umich.edu (CAEN Netnews)
Organization: University of Michigan Engineering, Ann Arbor
Lines: 16