The Bendix G-15 refurbished by [David at Usagi Electric] is well known as the oldest fully operational digital computer in North America. The question [David] gets most is “what can you do with it?”. Well, as a general-purpose computer, it can do just about anything. He set out to prove it. Can a 1950s-era vacuum tube computer handle modern physics problems? This video was several years in the making, was a journey from [David’s] home base in Texas all the way to CERN’s Large Hadron Collider (LHC) in Switzerland.
The G-15 can run several “high-level” programming languages, including Algol. The most popular, though, was Intercom. Intercom is an interactive programming language – you can type your program in right at the typewriter. It’s much closer to working with a basic interpreter than, say, a batch-processed IBM 1401 with punched cards. We’re still talking about the 1950s, though, so the language mechanics are quite a bit different from what we’re used to today.
To start with, [Usagi’s] the G-15 is a numeric machine. It can’t even handle the full alphabet. What’s more, all numbers on the G-15 are stored as floating-point values. Commands are sent via operation codes. For example, ADD is operation 43. You have to wrangle an index register and an address as well. Intercom feels a bit like a cross between assembler and tokenized BASIC.
If you’d like to play along, the intercom manual is available on Bitsavers. (Thanks [Al]!)
In the second half of the video, things take a modern turn. [David’s] friend [Lloyd] recently wrote a high-speed algorithm for the ATLAS detector running at the Large Hadron Collider at CERN. [Lloyd] was instrumental in getting the G-15 up and running. Imagine a career stretching from the early days of computing to modern high-speed data processing. Suffice to say, [Lloyd] is a legend.
There are some hardcore physics and high speed data collection involved in ATLAS. [Allison] from SMU does a great job of explaining it all. The short version is: When particles are smashed together, huge amounts of information is collected by detectors and calorimeters. On the order of 145 TB/s (yes, terabytes per second). It would be impossible to store and analyze all that data. Topoclustering is an algorithm that determines if any given event is important to the researchers or not. The algorithm has to run in less than 1 microsecond, which is why it’s highly pipelined and lives inside an FPGA.
Even though it’s written in Verilog, topoclustering is still an algorithm. This means the G-15, being a general-purpose computer, can run it. To that end, [Lloyd] converted the Verilog code to C. But the Bendix doesn’t run C code. That’s where G-15 historian [Rob Kolstad] came in. Rob ported the C code to Intercom. [David] punched the program and a sample dataset on a short tape. He loaded up Intercom, then Topoclustering, and sent the run command. The G-15 sprang to life and performed flawlessly, proving that it is a general-purpose computer capable of running modern algorithms.
Curious about the history of this particular Bendix G-15? Check out some of our earlier articles!
It’s amazing what’s possible when the manufacturer can’t remotely brick the device.
This thing is built like such a tank, I think if the manufacturer threw a literal brick at it, it wouldn’t hurt it!
kind of an overstatement seeing as it only does one algorithm among many that cern needs to process data, and too damn slowly to be useful. frankly i was more impressed by the machine being able to play the e1m1 soundtrack from doom. what they do at cern would be impossible on this level of equipment.
Well no crap sherlock ya know there is this concept of fun and sometimes people do things for the giggles
Naturally, it never had any chance of being a legitimate, viable alternative computing method for the most computational intensive environment on the planet. But, the point was to prove that an algorithm is an algorithm, and computers are good at computing those, regardless of how old it is.
Love your channel, David! I wish I had a shop like yours. I have so many old machines in storage (not as interesting as yours) I’d like to get running again.
to be clear my gripe is with the had writers, your work is spectacular. also critters. love the critters.
The good news is that when you restore a vacuum tube-based computer, they let you run whatever programs you want on it for fun.
i watch this channel religiously, i just found it a little lame how had resorted to such a blatantly clickbait title.
You must be fun at parties
Bold of you to assume he is ever invited to parties.
If this one is the same as the one that lives at the MARCH VCF museum at Infoage then I’ve met it. I always describe it as one of the earliest true digital computers who can do practically anything as long as the machine and the programmer understand it. (Sometimes I help the people in the museum out on a volunteer basis.)
I am Groot
Don’t forget the classic Story Of Mel, which concerns programming a slightly newer drum memory computer and an ethical quandary – after watching the Bendix videos I’ve a much better appreciation of the details in it.
https://users.cs.utah.edu/~elb/folklore/mel.html
One of my favourite old stories about these systems and corporate nonsense for sure.
Could you please fix that “TerraBytes” in the article? It’s kinda the hallmark of sloppiness in a text about computers.
Thank you for your kind correction! Fixed.
Those are really TerraIncognitaBytes and after processing they become TeraBytes. : – ]