[ih] Baran and arbitrary reliability from arbitrarily unreliable components

[Noel Chiappa]

    > From: John Day <jeanjour at comcast.net>

    > The ARPA people were outlining the general properties: distributed
    > control, packet switching, etc. But not specifying details like what
    > routing algorithm, how to do error correction, etc.

Actually, if you read the RFQ, that's not quite accurate. The main body of
the proposal is mostly written in fairly high-level terms, but Appendixes
cover a great deal of detail, including IMP-IMP packet formats, the checksum
algorithm to be used on the IMP-IMP links, a briefly sketched routing
algorithm, a network connectivity map, etc.

One Appendix starts out by saying: "This section, like the others, is
designed to provide guidlines to the contractor who may, if he [sic] wishes,
modify any part of the description in his proposal. Each modification will be
evaluated, and will be considered in the final contractor selection." So the
Appendixes weren't hard-and-fast requirements, but they weren't 'just for
illustration' either.


Interesting aside, from the body of the RFQ: "Since the HOST's staff can
program the IMP [!! - JNC], it is recommended that physical memory protection
be provided." That one got changed pretty quickly! :-)

	Noel