[ih] Users vs Hosts on ARPANET

[Noel Chiappa]

    > From: Brian Dear <brian at platohistory.org>

    > Anyone have any references to such data?

I don't know of any such data offhand, but that doesn't mean there wasn't any.


One thing I do know of are the so-called "ARPANET Directory" books, which
list many (but not _all_) people using the ARPANet. New versions came out
periodically (every year or two, perhaps?), and one can get some idea of
growth from them.

E.g. I have two (NIC 49000, March 1982; and NIC 50000, June 1984). These are
of course later than the time period you are concerned with, but they are
perhaps of some interest anyway. In the former, there are 389 pages (pp.
31-389) of names, at roughly 17 names per page (averaging over about 8 pages
or so), or about 6,600 names; the latter has 578 pages of names (pp 17-594),
at about 25 per page, for about 14,500.

For the machines/institutions I was familiar with (the ones at Tech Square at
MIT), these volumes appear to list most everyone; a few are missing, but it's
just a few. For the research group which I was in, almost everyone whom I can
think of is listed - faculty, staff, and grad students and those undergrads
who were part of the research group.

Interestingly enough, those numbers sort of roughly fits with the
approximately 'doubling in size every year or so' that we later observed in
the early Internet. If we assume an exponential growth model, with the
numbers above, it tracks back to a fairly small group of people in roughly to
1970 or so, which would be correct.

	Noel