Computer museum: Unix on PDP

Status: publiek -- Laatste wijziging: 9 maart 2016

Unix on PDP 11

The PDP 11 was delivered by Digital with several operating systems, but no Unix. Starting up Unix on a new PDP was every time a new challenge.

Unix V6 on PDP 11/60

The first step to run Unix was obtaining a source license from Bell Laboratories. The department did obtain its license in September 1977. Together with the license came a ½ inch tape or RK05 discs.

We could not use the Bell Labs tape, because the only supported PDP's were the big models (11/70, 11/45). Moreover it did not support the RK07 discs.

Luckily we could use the installation (and the know-how) of the Unité d'Informatique of the Université Catholique de Louvain. On this machine P. Verbaeten wrote the first prototype driver for the RK07. A Unix V6 system was made and put on tape. This tape was read on the PDP 11/60 and copied to disc. This was our first working Unix V6. (The procedure did work from the first time.)

Using this bootstrap system newer and better version, e.g. an RK07 driver using interrupts were made.

Unix V7 on the PDP 11/60

Around 1979 Bell Labs made a new Unix version (V7 : version 7) available. This new version did contain numerous new commands, some of which are still in use today:

Bourne Shell: This shell was the first one with structured commands, shell variables and several forms of input output redirection.
Make: Make uses the "modification time" available for every file in a Unix file system to describe and reconstruct software packages.
...

Unix V7 came also without support for PDP 11/60 or RK07. Since the Unité d'Informatique of the Université Catholique de Louvain did not yet run Unix V7 we went to the Vrije Universiteit Amsterdam, where A. Tannenbaum was running Unix V7 on a PDP 11/45. During a trip to Amsterdam out RK07 driver was integrated into Unix V7, a tape was made and with that tape we did boot Unix V7 on the PDP 11/60.

Unix V7 on PDP 11/34

Our PDP 11/34 did not have a magnetic tape. But since our PDP 11/60 had the same CDC 80 Mb disc, a bootable disc for the PDP 11/34 was prepared on the PDP 11/60.

Unix V7 from Digital Equipment

Officially Digital Equipment did not support Unix.

With the maintenance technicians we made the agreement that the hardware was OK, when their test programs did not produce error messages.

At the end of 1983 we found out that within Digital there was a very small group which distributed Unix V7 with support and drivers for all PDP 11 models and devices. Sources were distributed freely to all source licensees of Bell labs. From then on we have used that distribution.

Dennis Ritchie gives you more information about the early history of Unix and about the firsts C compilers. Even the first Unix manuals can be found.

And Dennis M. Ritchie's Memorial page contains a lot of references .

More information about Unix versions on PDP can be found on the PDP Unix Preservation Society Home Page.

Do you want to run your own Unix V5,6 or 7 on a PDP11 simulator on a PC?

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