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From: KVC%cit-vax@engvax.UUCP
Newsgroups: fa.info-vax
Subject: Checksum
Message-ID: <8508261932.AA13877@cit-vax.ARPA>
Date: Mon, 26-Aug-85 15:31:46 EDT
Article-I.D.: cit-vax.8508261932.AA13877
Posted: Mon Aug 26 15:31:46 1985
Date-Received: Wed, 28-Aug-85 02:53:56 EDT
Sender: daemon@ucbvax.ARPA
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Organization: the arpa internet
Lines: 19

There is an undocumented CHECKSUM command in VMS.  I know it works in V4.1,
and I seem to remember it in the past (V3) but can't be sure.  It's a little
odd.  The command is of the form:

	CHECKSUM[/image /file /output=filename] file.ext

The /IMAGE qualifier tells it to checksum a .EXE file in a special way, that
gives you the checksum for each image section and the image header.  The
normal operation of CHECKSUM is to calculate the checksum of the file (I
do not know what the mapping algorithm is) and leave the result in the DCL
symbol CHECKSUM$CHECKSUM.  Wierd....  No other output is produced unless you
are using /IMAGE, in which case it prints the results of the image section
checksums to SYS$OUTPUT or to the output specifed with /OUTPUT=.  It also
leaves a checksum in the DCL symbol when you use /IMAGE.

	/Kevin Carosso           engvax!kvc @ CIT-VAX.ARPA
	 Hughes Aircraft Co.
	"Finder of lost features..."