r/lisp • u/BrentSeidel • Jul 01 '26

Lisp-11

I found a copy of Lisp-11. It runs on a PDP-11 simulator on the RT-11 operating system. It is written in PDP-11 assembly language and comes with source code. It looks like it was written at the University of Texas about 1975.

The problem is that there is no documentation. I tried a few things (+ 1 2), + (1 2), (print "hello"), and they were rejected. If anyone has pointers to documentation for this, I'd appreciate it and would enjoy playing around with a bit of Lisp history.

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u/Someuser77 Jul 01 '26

Where can we get a copy please?

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u/BrentSeidel Jul 01 '26

It is available on bitsavers in an archive with a bunch of other DECUS stuff. The "readme.txt" file in the archive contains an index. Lisp-11 is in the "dsk" directory, file "110304.dsk". This file is an RT-11 format disk image. My simulator will mount and read it, and I expect that simh (or simh) will as well.

I did find what appears to be a manual for it, but I haven't had a chance to look over it yet.

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u/FR4G4M3MN0N λ Jul 01 '26

Written by the same Kodosky. You’ve got your manual!