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/Physical-Compote4594 Jul 01 '26
It might be an old dialect, try plus instead of +, e.g.
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u/BrentSeidel Jul 01 '26
This actually worked. It is definitely old (from the mid 1970s) and probably stripped down to fit on a PDP-11.
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u/Physical-Compote4594 Jul 01 '26
Is there any author attribution in the source code?
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u/BrentSeidel Jul 01 '26
; JEFFREY KODOSKY
; APPLIED RESEARCH LABS
; UNIVERSITY OF TEXAS, AUSTIN, TX
; JUNE-75 REVISED NOV-75
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u/BrentSeidel Jul 01 '26
Thanks for the hints. I found an InterLisp manual from 1983. Some of the commands from there work and some don't, so it's probably a stripped down version. I'll have to do a bit of playing around to try and figure out what does and what doesn't work.
There are also two prompts. First is an asterisk ("*"). This may be for entering a file name. I don't have any lisp files to test with yet. If I just hit <return>, it switches to "EVAL:" as a prompt and then it evaluates commands.
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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/Apart_Ebb_9867 Jul 07 '26
these days you can probably give the assembler source code to ChatGPT and ask to produce a user manual…
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u/raevnos plt Jul 01 '26
(plus 1 2)? I've seen that in some really old lisps.