The LittleGP-30: A tiny recreation of a very big deal from the 1950s

In these days of multi-gig OSes, we cast our eyes back to something both much bigger and much smaller. The Reg FOSS desk only recently came across interesting news about a very cool project: Jürgen Müller's LittleGP-30, a 2017 recreation on an FPGA of the Librascope LGP-30, a seminal early computer from the 1950s. What …

[ICL1900-G3]

Bendix G15

Anyone interested in this sort of thing should have a look at the Usagi Electric videos on YouTube, especially the ones about the Bendix G15. Dave Lovett is a genius at getting old stuff to work. He's also a great presenter and seems like a good guy.

https://m.youtube.com/playlist?list=PLnw98JPyObn3QSIwUz5Iv6NA1x-uGFqAa

[Anonymous Coward]

Re: Bendix G15

Kinda cool how the Bendix G15D's Programmer's Reference Manual advocates for the use of Sexadecimal notation (page 4, Table 1) ... it's that version of hexadecimal where letters A-F are replaced by U-Z ... naughty naughty! _{(not to be confused with base 60 sexagesimal ... also naughty!)}

[Chris Gray 1]

Memories

Way kewl! Brings back memories of playing with old Teletype machines, etc.

That Flexowriter is much smaller than the big desk teletype we got from a seller (government surplus??). That one came on its own steel desk that you could park a car on. The solenoid for the paper tape punch could probably have punched a hole through your hand if you could get it in the wrong place! The reader was a whole separate unit that you could slide out.

My friend spent hours tracing the circuits in the beast.

The mechanicals in those old Baudot (sp?) machines was magical to watch.

[frankvw]

Re: Memories

A copy of the LGP-30 programming manual is still available online. It starts by explaining that:

"Programming is planning how to solve a problem. No matter what method is used -- pencil and paper, slide rule, adding machine, or computer -problem solving requires programming. Of course, how one programs depends on the device one uses in problem solving."

Which is the exact same explanation I used Way Back When while teaching software development. Compare that to IBM's "A ... is a sequence of non-whitespace characters separated by whitespace characters" and "This page intentionally left blank." Huh!

And then it starts delving into the intricacies of "recirculating registers" and the physics of the rotating drum that are central to Mel's legendary heroics. :-)

[elsergiovolador]

GP

Okay, for a second - reading headline - I thought someone came up with a little can sporting a camera, microphone and a speaker.

Basically an AI GP that you can pop in the bathroom or kitchen and talk to about your health issues whenever you want. It could even have a little thermal printer to get you the scripts.

Fortunately I was wrong.

[Anonymous Coward]

Re: GP

There is a new improved more realistic version. Where you wait 6weeks for it to boot, it has no camera or microphone because it just repeats "you are depressed, glad you came to see me to get this off your chest, come back and see me later - next patient please"

[J. Cook]

Re: GP

But if you curse at it, does it issue you tickets in leiu of toilet paper or the three seashell method?

mines the one with the "Demolition Man" movie logo on the back.

[David 132]

Re: GP

J. Cook, you are fined three credits for a written violation of the Verbal Morality Code.

[JWLong]

Drum Memory

I never had a chance to work on any drum type of equipment.

The first type was DTL(diode transistor logic) for Brunswick in bowling centers. This equipment was developed by RCA independently and was first offered in 1969. It used iron oxide core memory with mechanical memory select relays.

"Drum and valves(tubes)" just sounds so cool to be able to learn on, wish I could have been there then!

After DTL, everything went TTL using Z-80's everywhere.

ICL1900-G3, thanks for the link, now I have something to soak my diminishing brain on for awhile!

[keithpeter]

The original LGP-30: Edward Lorenz had one of those...

https://en.wikipedia.org/wiki/Lorenz_system

https://galileo-unbound.blog/2024/04/03/a-short-history-of-chaos-theory/

Track down a copy of Chaos by James Gleick for the full story. A really important root cause analysis - an apparent anomaly not written off as a 'computer glitch'.

[leocomerford]

Re: The original LGP-30: Edward Lorenz had one of those...

Yes, the project which led to chaos theory and the “butterfly effect” conceit. In fact that’s the same LGP-30 project, mentioned in the article, which Margaret Hamilton (and Ellen Fetter) worked on: https://www.quantamagazine.org/the-hidden-heroines-of-chaos-20190520/ . I’m afraid that the Reg missed the lede here somewhat!

[Liam Proven]

Re: The original LGP-30: Edward Lorenz had one of those...

Huh. Well, fair enough.

I knew that Lorenz used the machine, but I picked its early role in the development of BASIC as something people would identify or connect with more. My mistake.

[keithpeter]

Re: The original LGP-30: Edward Lorenz had one of those...

No mistake, your judgement might well be correct.

Just an extra thread in the tapestry.

[Dr. Ellen]

Oh, "The Story of Mel"!. Somebody read that back in he Nineties, and said it was the first time she really understood me. An entertaining tale, capable of enlightening the non-techie.

[gormful]

I wish more of today's "developers" (like Edward Coristine) understood how tall the scaffolding underneath them is. Let's see them try to reimplement the US Socail Security systems on an LGP-30!

[Antron Argaiv]

Please use his full name: Edward "Big Balls" Coristine

(there may be another, totally innocent , Edward Coristine, and we wouldn't want any confusion)

[HuBo]

Quite Cool

A nicely minimalist system, with sixteen 16-bit-wide instructions (stored in 31-bit words), 3 internal registers, 16 KB of Drum "RAM". I imagine this can be readily implemented in a Lattice up5k using FOSS tools Yosys and NextPnr ... or even as a virtual CPU in a Raspberry Pi Pico 1 or 2 (as far as functioning is concerned). One great aspect of Müller's artifact here is definitely the reproduction of the tangible UI (with LCD and HDMI!) imho.

I wonder if a Flexowriter keyboard could be sourced and used for input ... maybe also some Fresnel lenses to magnify a tiny output screen as in Brazil (1985)! Such machinery could literally smoke DOPE programs (eh-eh-eh!)!

[swm]

Re: Quite Cool

Actually DOPE stood for Dartmouth Oversimplified Programming Experiment that I wrote in 1962. It was a precursor to BASIC.

I have also written a simulator for the LGP-30 in Java with all of the buttons etc. The LGP-30 executed about 60 instructions per second unless you cleverly organized data so it didn't have to wait a revolution to access it.

A fun machine.

[UNC70]

I have manuals and some programs for the LGP-30

Tried to preserve an LGP-30 in pristine condition. It was the first computer at UNC Chapel Hill and was in the Thurstone Psychometric Laboratory. We had placed it in storage with large signs describing which professor to contact before it was moved. Unfortunately, someone in the eatrly 1970s decided it was surplus, and the State of NC sold it for scrap!

I really need to find a home for all the stuff I have from the 1950s onward. Hardware, software, and business related.