Plan 9 used Datakit as its network for quite a while. The Gnot terminals had an INCON interface, a megabit (approximately) twisted pair adjunct to Datakit. I had an INCON link running over a T-1 link to my house - great excitement back in the day. (The kernel downloaded over the line and booted the machine up to the window system - there was no local disk - from power up, in 7 seconds.) NJ Bell needed to install a new nitrogen-pressurized 26-pair cable, supported by a new telephone pole, to set it up, because I had already used up all available pairs on the existing line to my house. All included at no extra cost. (You pay for the service, not its construction.)

When the internet became unavoidable, we used Plan 9's import mechanism to import the single external TCP/IP interface from our gateway machine, over Datakit, to the Gnots. We did the same, but importing now over IL (an ethernet protocol built by Phil Winterbottom) when our terminals became PCs.

That's how I remember it, at least, but I might have got some details wrong. I think much of this is covered in http://doc.cat-v.org/plan_9/4th_edition/papers/net/

-rob

On Wed, Jun 22, 2022 at 10:13 AM Larry McVoy <lm@mcvoy.com> wrote:

On Tue, Jun 21, 2022 at 05:56:02PM -0600, Jacob Moody wrote:
> I recently stumbled across the existence of datakit
> when going through the plan9foundation source archives.
> Would be curious to hear more about its involvement
> with plan9.

Pretty sure datakit predated Plan 9, didn't Greg Chesson work on that?
He was my mentor at SGI, my memory is datakit was sort of early on in
his career and then he did XTP, which nobody knows about but I believe
is still used by the military.

Unless the early Bell Labs datakit and the Plan 9 datakit are different
things.