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

Paul Ruizendaal pnr at planet.nl
Wed May 24 19:20:23 AEST 2017

>> I'm looking into the history of Spider and early Datakit. Sandy Fraser
>> was kind enough to send me the 1974 report on Spider
> Is that online? If not, any chances you can make it so?

It is a paper copy, but I can make a scan for you.

> which contains the drivers tiu.c, mpx.c - I'm not sure what other files there
> are part of it?

I think tiu.c might be all. The TIU ("terminal access unit") was the network card,
so to speak (actually some 5 boards in a rack) and did a lot of the heavy lifting.

From the tiu.c file I understand that a DR11-B parallel I/O card was used on
the PDP side to connect to the TIU, and that access was structured as a block
device driver.

> I'm not at all clear how this stuff got there - someone at Bell must have just
> dumped the contents of the 'dmr' directory, and sent it all off?

Looks like it.

> The PWB1-based MIT systems also have a lot of the Spider software (although it
> was never used). It's a slightly different version than the one above: 'diff'
> shows that 'tiu.c' is almost identical, but mpx.c has more significant
> differences.
> It also contains man pages, and sources for some (?) user programs; I have the
> source and manpage for 'nfs'. What other names should I be looking for? (The
> man page for 'nfs' doesn't list any other commands.) I'll put them up
> momentarily.

I think that in the lifespan of Spider (1972-1978) there were 3 main network
programs (basing myself on McIlroy's Unix Reader):
- 'nfs' an FTP-like program to copy files to/from a central File Store.
   I'm not sure whether the File Store was a Unix machine or something else.
- 'ufs' not sure what it was, but I think a telnet-like facility
- 'npr' a network printing program

A little surprising, but no reference to a Spider mail program in that document.

> In the meantime, I'll append the 'tiu' man page.

Thanks! It is from October 1973, which sounds right for Spider. I guess this
code is the first networking on Unix, predating the UoI work by about 18 months.

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