Exploring PDP-1 Lisp (1960) • Hacker News Board

Re: Exploring PDP-1 Lisp (1960)

#11

Post by ozymandiax » Tue, Jun 30, 2026, 2:04 AM UTC

gwern wrote: post #9

blooalien wrote: post #5

Earlier quoted context omitted.

> Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's been lost :-) Some of us who remember actually playing with Eliza are absolutely amused by all the hype around LLMs (because it's so similar to the hype heard from "normies" who saw Eliza and thought we were "just around the corner from real AI"; The same folk who thought we'd all have a flying car in ever…

ELIZA has been refound: https://sites.google.com/view/elizaarchaeology/home

Actually, https://github.com/cl-aip/eliza/ would be a great starting point for a backport to Lisp 1.5. Hmmm...

Re: Exploring PDP-1 Lisp (1960)

#12

Post by fsckboy » Tue, Jun 30, 2026, 2:18 AM UTC

ozymandiax wrote: post #2

Written by Peter Deutsch, then a then-high school student on a tiny 4K (admittedly, 4K 18-bit words) machine. Amazingly usable - and lives on in the Python REPL concept. Our PiDP-1 simulator on github lets you try it out on any Linux machine (not just a Raspberry PI): https://github.com/obsolescence/pidp1 Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's be…

>Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's been lost :-)

you can run eliza in emacs, just " M-X doctor " enter

Re: Exploring PDP-1 Lisp (1960)

#13

Post by ozymandiax » Tue, Jun 30, 2026, 2:22 AM UTC

I was wrong - it was not Peter Deutsch who ported Eliza to Lisp, it was Bernie Cossell at BBN (one of the famous IMP Guys a few years later!). And it is here:

https://github.com/jeffshrager/elizagen.org/tree/master/1966...

That makes a PDP-1 Lisp backport very tempting... amazing how ancient code comes back from presumed extinction.

Re: Exploring PDP-1 Lisp (1960)

#14

Post by ozymandiax » Tue, Jun 30, 2026, 2:48 AM UTC

fsckboy wrote: post #12

ozymandiax wrote: post #2

Written by Peter Deutsch, then a then-high school student on a tiny 4K (admittedly, 4K 18-bit words) machine. Amazingly usable - and lives on in the Python REPL concept. Our PiDP-1 simulator on github lets you try it out on any Linux machine (not just a Raspberry PI): https://github.com/obsolescence/pidp1 Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's be…

> Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's been lost :-) you can run eliza in emacs, just " M-X doctor " enter

But we'd need to backport emacs to the PDP-1 then :-)

Re: Exploring PDP-1 Lisp (1960)

#15

Post by AdieuToLogic » Tue, Jun 30, 2026, 3:09 AM UTC

ozymandiax wrote: post #2

Written by Peter Deutsch, then a then-high school student on a tiny 4K (admittedly, 4K 18-bit words) machine. Amazingly usable - and lives on in the Python REPL concept. Our PiDP-1 simulator on github lets you try it out on any Linux machine (not just a Raspberry PI): https://github.com/obsolescence/pidp1 Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's be…

> Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's been lost :-)

When in doubt, there is always the option to implement Eliza in a Forth[0] embedded within a dish washing machine's firmware. It could converse about one's thoughts regarding pre-soak techniques. :-)

0 - https://www.forth.com/starting-forth/

Re: Exploring PDP-1 Lisp (1960)

#16

Post by retrac » Tue, Jun 30, 2026, 3:59 AM UTC

sourdecor wrote: post #3

Kind of a non sequitur: I bought "The Genius of Lisp"[0] and it is not what I thought (a book entirely devoted to the history of Lisp - from MIT to Common Lisp and then to Clojure). Would anyone recommend another book? [0]: https://www.amazon.com/Genius-Lisp-Cees-Groot/dp/1069886416/

It's not a history book or even all that much a book about Lisp, despite its name, but Lisp in Small Pieces incidentally covers a lot of Lisp history. The book at its core is about implementing compilers and interpreters. It starts with something close to the McCarthy meta-evaluator, and the rest of the book iteratively elaborates on why the naive meval is not a practical programming language, somewhat mirroring the evolution of historical Lisp implementations in the process.

It dates to the early 90s so it doesn't touch on Clojure or anything recent. The bibliography and citation is excellent.

> Literature about Lisp rarely resists that narcissistic pleasure of describing Lisp in Lisp. This habit began with the first reference manual for Lisp 1.5 [MAE+62] and has been widely imitated ever since. We'll mention only the following examples of that practice: (There are many others.) [Rib69], [Gre77], [Que82], [Cay83], [Cha80], [SJ93], [Rey72], [Gor75], [SS75], [A1178], [McC78b], [Lak80], [Hen80], [BM82], [CH84], [FW84], [dRS84], [AS85], [R3R86], [Mas86], [Dyb87], [WH88], [Kes88], [LF88], [Dil88], [Kam90].

https://www.amazon.ca/Lisp-Small-Pieces-Christian-Queinnec/d...

Re: Exploring PDP-1 Lisp (1960)

#17

Post by pmcjones » Tue, Jun 30, 2026, 4:14 AM UTC

sourdecor wrote: post #3

Kind of a non sequitur: I bought "The Genius of Lisp"[0] and it is not what I thought (a book entirely devoted to the history of Lisp - from MIT to Common Lisp and then to Clojure). Would anyone recommend another book? [0]: https://www.amazon.com/Genius-Lisp-Cees-Groot/dp/1069886416/

Try these:

https://softwarepreservation.computerhistory.org/LISP/lisp15...

(The third one includes the source code to PDP-1 Lisp.)

Re: Exploring PDP-1 Lisp (1960)

#18

Post by kqr » Tue, Jun 30, 2026, 8:57 AM UTC

ozymandiax wrote: post #2

Written by Peter Deutsch, then a then-high school student on a tiny 4K (admittedly, 4K 18-bit words) machine. Amazingly usable - and lives on in the Python REPL concept. Our PiDP-1 simulator on github lets you try it out on any Linux machine (not just a Raspberry PI): https://github.com/obsolescence/pidp1 Posting this in the hope that someone will feel triggered to backport Eliza, it was done in the 1960s but it's be…

I am very impressed by the simulator, and I really wish I could defend taking time to dig into PDP-1 programming. You make it look like an absolute blast!

Re: Exploring PDP-1 Lisp (1960)

#19

Post by pjmlp » Tue, Jun 30, 2026, 10:00 AM UTC

ozymandiax wrote: post #8

blooalien wrote: post #7

Earlier quoted context omitted.

Fun times, gettin' in early on the "tech scene" and watching it progress so quickly (yet at the same time so slowly in many ways compared to how it could have gone had greed and ignorance not held it back by decades). :)

I was born too late (not a bad thing necessarily) to have experienced that founding era. But I think that for later generations, there's a lot to learn still from what evolved in the earliest years. We've gained a lot since then, but we also lost a lot. Mean and lean programming, closeness to the hardware, inventiveness. And the liberating absence of 'software stacks'... It's fascinating how on such a tiny computer,…

Which is yet another reason to folks open their minds to what is actually possible on their super computers, instead of thinking only C and similar languages will deliver.

Re: Exploring PDP-1 Lisp (1960)

#20

Post by ozymandiax » Tue, Jun 30, 2026, 10:09 AM UTC

pmcjones wrote: post #17

sourdecor wrote: post #3

Kind of a non sequitur: I bought "The Genius of Lisp"[0] and it is not what I thought (a book entirely devoted to the history of Lisp - from MIT to Common Lisp and then to Clojure). Would anyone recommend another book? [0]: https://www.amazon.com/Genius-Lisp-Cees-Groot/dp/1069886416/

Try these: https://softwarepreservation.computerhistory.org/LISP/lisp15... https://softwarepreservation.computerhistory.org/LISP/lisp15... https://softwarepreservation.computerhistory.org/LISP/lisp15... (The third one includes the source code to PDP-1 Lisp.)

Wow! How did I manage to miss this treasure trove! Thank you.