[TUHS] Unix with TCP/IP for small PDP-11s

Clem Cole clemc at ccc.com
Sat May 20 03:39:41 AEST 2017

My quick answer is yes, this sounds cool.

>From that time, that two attempts to network 40 class systems that I know
about were:

   -  As I have mentioned in the past, in the late 1970s CMU had developed
   an 8085 later 8086 based Multibus board that would eventually begat the
   Cisco AGS, called the CMU distributed Front-End.   It was an attempt to get
   IP connected to the 11/40 class systems, by splicing them into the 11's
   with an DR-11B or C (I've forgotten which).   But the primary protocol
   processing was done on the FE and not in the UNIX kernel.     Phil Karn
   might remember what happened to that stuff, I do not believe I still have
   - Shortly thereafter @ Tektronix had 3Com's UNET.  I was primarily
   running on the 11/70 and that was what we used to develop against the Cyber
   and VMS IP/TCP's we wrote.  We also had it on an 11/44 but both of those
   are 45 class.     We did try to run on an 11/60 - which is 40 class as you
   asked, and we did get it work as I recall after a fashion.   But we did not
   push it very hard;as we had built a front end that in the same vein as the
   CMU device, called the NIBB - Network Interface Black Box, which was a Z80
   that did the same sort of thing and the need was not there.

 I was under the impression the 2.X folks may have tried to do it later
with all the thunk code.  But that was all after my work.   Fred Canter at
DEC might have tried something in later versions of Ultrix/PDP11, we should
look at the sources in his stream had see what he did too.


On Fri, May 19, 2017 at 11:15 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu>

> I'm trying to find out if there is any existing Unix for the PDP-11
> which supports TCP/IP on /40-/34-23 class machines (i.e. non-I+D
> machines)?
> Does 2.9 BSD with TCP/IP (assuming such a thing exists) fit on those
> machines? (I know 2.9 does run on them, but I don't know about the TCP/IP
> part.)
> The reason I ask is that MIT did a TCP/IP for V6 which would run on them
> (only incoming packet de-mux is in the kernel - the TCP is in with the
> application, in the user process), which has recently been recovered from a
> backup tape.
> I'm trying to figure out if there is any use for it, as it would take some
> work to make it usable (I'd have to write device drivers for available
> Ethernet cards, and adapt an ARP implementation for it).
>         Noel
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