Re: [9fans] datakit

[dmr@plan9.bell-labs.com]

Geoff's brief recapitulation of Datakit is pretty
much on the mark.  I'd emphasize these aspects:

It definitely was a logically circuit-switched network.
This meant (e.g) there were natural ways for requesting bandwith
allocation (instead of inferring flows), though I don't
think this was really taken advantage of.

The design was meant to cater to host-to-host communication
and this was the way we really used it in our own group
and to some extent throughout Bell Labs.  However, most
of the sales were as serial asynchronous concentrators
over modems.  Direct host interfaces were always relatively
expensive; at the start, probably not too much more than Ethernet
interfaces, but the rapid growth of Ethernet and consequent
cost reductions wiped out the more proprietary scheme.

(There was indeed better local security because DK was not
a broadcast, shared-medium network like EN, but
that's not where most people's problems are today).

In the aftermath, perhaps the most valuable effect of
dealing with Datakit was to enourage the generalized
and flexible approach to networking begun in 8th edition Unix
that is carried forward into Plan 9.

	Dennis