need POSIX cksum tables

James W. Williams williams at nssdcs.gsfc.nasa.gov
Tue Aug 7 01:30:22 AEST 1990


From:  James W. Williams <williams at nssdcs.gsfc.nasa.gov>

I am implementing, for BSD 4.4, the POSIX cksum program as described in
P1003.2/D10.  This program uses table look-up to calculate a CRC
"checksum" for each of its file arguments.  This table consists of 256
hexadecimal constants and it would be extremely tedious and error-prone
for me to type this in.  If someone out there on the committee has this
table on line and could mail it to me, I would be most grateful.  So as
not to waste net bandwidth, and clog my mailbox with multiple copies of
the table, I suggest you just let me know that you have it, and I'll
pick a random person to actually send it to me.

While I have your attention, the section on this program, 4.9, is
titled "cksum - Display file checksums and block counts".  Given that
this program, unlike the sum programs of BSD and system V, prints byte
counts, not block counts, shouldn't the section title be "cksum -
Display file checksums and byte counts"?

Also, it is noted that this program is not backward compatible with
either the BSD or system V versions of sum, thus it was given a new
name.  It is further noted that the term "checksum" is used for
historical reasons, even though the algorithm given is not,
technically, a checksum.  This seems oddly inconsistent.  Given that
the name is changing, why not call it crcsum, or just crc?

Thanks for your help and attention,

Spoken: Jim Williams             Domain: williams at nssdcs.gsfc.nasa.gov
Phone: +1-301-555-1212           UUCP:   uunet!mimsy!williams
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Volume-Number: Volume 21, Number 14



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