Re: TCP adoption in 1984

On Tue, May 5, 2026 at 7:35 AM Lawrence Stewart via Internet-history <
[email protected]> wrote:

> I think the microcode support for hardware in the Alto gave people a false
> impression of how easy it would be to build Ethernet controllers.  If I
> remember correctly, the Unibus Ethernet was a full hex card.  The first
> 3COM board was made to fit in a multibus form factor, but only by making it
> half duplex (I think).  Incidently, Xerox in El Segundo built a single-chip
> 3 MB Ethernet around 1982, although it would only run at half speed.  At
> PARC we used it for the Etherphone project, with an Alto gateway using a 3
> Mb board with a half-speed crystal.
>

Building good, full-speed Ethernet cards/chipsets remained a problem until
the end of the 1980s. (Not helped by a perception due to bad theory papers
that Ethernet capacity was capped at a fraction of its nominal bandwidth).
I remember a talk by Van Jacobson, I think in 1988, and I believe as an
aside in his SIGCOMM '88 talk and referencing Dave Boggs' earlier
presentation in the same session on Ethernet capacity (where he demolished
the poor theory papers). Van benchmarked various 10Mb Ethernet interfaces
and showed them lacking.

Speaking of evolutions -- there was a huge jump in the availability of
affordable systems during the 1980s. Remember the early SUN workstations
were a custom CPU board using a Motorola 680x0 processor connected to a
stock multibus, later VMEbus, and third-party interface cards.  There were
lots of copycats. By the late 1980s, most Computer Science departments on
CSNET had internal Ethernets delivering email to individual desktops (so
their link to the outside world was CSNET, or UUCP, or both over dialup
lines, but internally they were running TCP/IP).  When NSFNET appeared,
switching to full Internet connectivity was relatively easy. CSNET already
used domain names so the primary problems were (1) renumbering (ugh, but
doable) and (2) campus politics (was CS or campus IT in charge of the link,
etc. [NSF's requirement that connectivity be offered throughout campus
simplified that fight quite a bit]).

Craig

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