[TUHS] CRC calculation in the 1980s

Noel Chiappa jnc at mercury.lcs.mit.edu
Tue Sep 19 21:42:29 AEST 2023


    > From: Paul Ruizendaal

    > Any suggestions as to why the on-the-fly algorithm did not catch on
    > more in the 1980's? Maybe it was simply less well known than I think?

I can't answer that directly, but I will point you at IEN-56, "CRC Checksum
Calculation", by Dave Reed (11-Sep-78):

    https://www.rfc-editor.org/ien/ien56.pdf

Dave wanted the INWG to use a more powerful (in terms of detecting errors)
CRC, instead of the simple summation eventually adopted, in TCP and IP. So he
produced code to implement a particular CRC, to show people that it would not
be particularly expensive (whether in time, or space, I don't alas recall
definitively; speed would have been an important consideration, when
competing with the summation, though).

This would have been close to the leading edge of our knowledge at the time;
Dave liked playing around with math, and at about that time he did a very
fast DES implementation.

	Noel


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