rHXN - Exploring PDP-1 Lisp (1960)

Exploring PDP-1 Lisp (1960)

https://obsolescence.dev/pdp1-lisp-introduction.html

By: ozymandiax

HN Link

ozymandiax - 10 hours ago

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 been lost :-)

blooalien - 10 hours ago

> 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 every garage by now, LOL!). Still really impressed by what LLMs actually can do though, despite them being not much closer to true "thinking machines". ;)

ozymandiax - 9 hours ago

When we visited some of the 1970s 'heros' of the MIT AI Lab, we were told the informal story behind SHRDLU, the AI living in a PDP-10 3D world. How this graphical AI triggered the first AI Summer --

https://www.youtube.com/watch?v=8ZGQcJVdjj8

-- and as it fell short of first impressions, perhaps the first winter too?

blooalien - 9 hours ago

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). :)

ozymandiax - 9 hours ago

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, something like a comfortable interactive Lisp just emerged. Relatively comfortable.

pjmlp - 1 hour ago

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.

gwern - 9 hours ago

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

ozymandiax - 9 hours ago

We already have it running on the PDP-10 reconstruction, and it is known that people around Deutsch at BBN ported it back to the PDP-1. But that version has been lost. From the link you gave, a backport would be feasible... especially because the PDP-1 simulator has the full memory upgrade to 64Kw!

ozymandiax - 9 hours ago

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

kqr - 2 hours ago

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!

AdieuToLogic - 8 hours ago

> 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/

fsckboy - 8 hours ago

>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

ozymandiax - 8 hours ago

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

ozymandiax - 8 hours ago

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.

sourdecor - 10 hours ago

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/

pmcjones - 6 hours ago

Try these:

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

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

ozymandiax - 1 hour ago

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

ozymandiax - 10 hours ago

The PDP-1 Lisp page has 4 rather good books linked as PDFs. Oh - but all on the earliest history of Lisp as well! That is not what you're looking for I think.

retrac - 7 hours ago

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...