Sean Haas
Advent of Computing
Welcome to Advent of Computing, the show that talks about the shocking, intriguing, and all too often relevant history of computing. A lot of little things we take for granted today have rich stories behind their creation, in each episode we will learn how older tech has lead to our modern world.
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Episodes
Episode 185 - Is EMUL-8ion a Form of Flattery? 06.07.2026 1:01:24
EMUL-8 is a fascinating programming language. It's described in just one paper from 1977. It's a mix of features from APL, LISP, ALGOL, and SNOBOL. And, I think, it's a wonderful window into how counterculture and home computing collided.
Episode 184 - What Is A Programming Language? 21.06.2026 1:09:34
I mean that both in the specific and the abstract. This episode we are looking at APL, which stands for A Programming Language. APL was developed in the mid 50s, but didn't see a working implementation until 1965. It's a language that truly looks like no others, but has some odd parallels to everything from BASIC to LISP to linear algebra. Learn APL at: tryapl.org https://www.jsoftware.com/papers/...
Dale Biagio - Hello, World! 14.06.2026 31:44
Dale Biagio(author of Hello, World!) got in touch with me recently. He said he had a book full of short histories of programming languages. Better still, it has sources! How could I resist! In this episode I sit down with Dale to talk about the intersection of technical and human histories. You can find more about Hello, World! at Dale's website: https://helloworldthebook.com/
Episode 183 - A Digital Gap? 31.05.2026 54:58
I've been browsing old compur surveys and trying to build up a comprehensive data set. What I've found is a little surprising: between late 1945 and 1949 only 10 new computers entered service. Once we get to the 50s that number explodes. What's going on here? What caused the gap between the first digital machines and the explosion of computers in the 50s? In this episode I try to answer that quest...
Episode 182 - Spinning Memories 18.05.2026 58:31
What connects IBM, the NSA, the Third Reich, and high fidelity recordings of symphonies? The answer is: magnetic drum memory. Join me as I lose all track of scope and plot to discovery just how and why magnetic drum memory was invented. Like Advent of Computing? Then check out the after show! Adjunct of Computing is now LIVE: YouTube Spotify Apple Podcasts
Episode 181 - RAYDAC 03.05.2026 1:12:18
In 1947 Raytheon signed a contract to make their first computer. It would be their last... at least for many many years. The fruits of this contract was RAYDAC. Early digital computers were odd, to say the least. And RAYDAC distinguishes itself. From zig-zag delay lines to hunting tapes to freon cooling, it truly is a unique machine. Selected Sources: https://ed-thelen.org/McGee_Book-4.2.2.pdf - M...
Episode 180 - You Wouldn't Magnetize a Tape! 19.04.2026 1:06:28
The image of a mainframe is almost always accompanied by it's companion: the magnetic tape drive. For decades magnetic tape served as the medium of choice for computing. It was faster than punch cards, and more available than hard drives. But where did it come from? Is it a borrowed technology like the vacuum tube? Like Advent of Computing? Then check out the after show! Adjunct of Computing is no...
Episode 179 - Programming Block by Block 04.04.2026 1:01:59
In which we discuss GPSS: the General Purpose Simulation Language. As for as languages go, this is a unique one. It's designed for certain types of simulations. It's code is just a handy way to feed a flowchart into a computer. It's design is closer to an analog computer than it is to a programming language. Yet GPSS is Turing Complete. Step inside and prepare to be... confused! The big source of...
Episode 178 - The Programma 101 22.03.2026 1:02:46
The Olivetti Programma 101 isn't quite like any other machine. On first glance it looks like a big desktop calculator. Inside, it's a purebred computer... but strange one. It uses twisted spring steel for memory, has no addresses, and it's machine code looks more like a spell than a program. It's existence is due, in no small part, to a man being very mean to GE engineers. Like Advent of Computing...
Dan Temkin - Forty-Four Esolangs 09.03.2026 51:59
Dan Temkin has been a long time friend of the show. I finally got the chance to sit down and talk with him about one of his latest projects. Forty-Four Esolangs is a "The first artist's monograph of programming languages". During this interview we keep circling around one very crucial question: what really is a programming language? Get the book and learn more about esolangs here: https://danielte...
Episode 177 - Getting Real with RSX 23.02.2026 57:49
Who wants to hear me make incorrect assumptions about old software? RSX is a system that, from the outside, can sound like it has a similar story to that of UNIX. First developed for the PDP-15 in 1969, RSX becomes much more well known when it migrates to the PDP-11. It becomes a multitasking and multiuser system. A key difference is niche. While UNIX is a very general purpose system RSX is built...
Episode 176 - Is That Even UNIX? 09.02.2026 1:02:22
UNIX is beloved by many. It's the classic minicomputer operating system. It's big, it's powerful, it's multitasking, and it has some very specific memory requirements. So what happens when you try and get UNIX to run on a microcomputer? Hilarity ensues. Today we are looking at 3 small versions of UNIX: OMNIX, LSX, and CROMIX. And, I'll tell you, one of these is closer to vaporware than the others.
Episode 175 - SNOBOL? That's Disgusting! 28.01.2026 1:05:59
Today we are talking about one of the most unique languages I've ever come across. SNOBOL emerges from the early days of programming. It's first compiler is implemented on the back of an envelope. It only has one data type, and only one format for every line of code. It's the bane of Chester, and center of an office drama! What's not to love? Selected sources: https://dl.acm.org/doi/epdf/10.1145/9...
Episode 174 - The Bell Model I 12.01.2026 1:02:50
We are getting back to the actual digital family tree. In 1937 George Stibitz built a tiny binary adding circuit on his kitchen table using scraps he "liberated" from his job at Bell Labs. In 1940 he demonstrated a machine he called a computer. That research forms one of the foundations of modern computing. It also forms a weird temporal phenomenon that I have yet to name. Maybe the Curse of '37?...
Episode 173 - Hybrid Programming 29.12.2025 1:02:59
Hybrid computers are composed of a digital computer linked to an analog computer. That leads to an interesting challenge: how do you write software for one of these things? The analog side actively resists programming, while the digital side can't comprehend of continuous values. In the 1960s specialized languages appeared that tried to bridge this divide. And, I assure you, they are not at all li...
Episode 172 - Analog/Hybrid 15.12.2025 1:05:04
In 1945 the first electronic digital computers sparked to life. Number crunching was instantly changed forever! The perfect technology had arrived, and there was never even a competition, right? Well, not so much. The simple fact is that computers sucked for decades. Digital machines have all kinds of inherent pitfalls. There was another entire lineage of computers that existed in the shadow of di...
Episode 171 - What Is a 4GL? 24.11.2025 54:42
Last episode I said that Fourth Generation Languages were a topic for another time. Well... this counts as another time. Today we are trying to figure out what exactly makes a language 4th Generation. Along the way we will see why the term bugs me so much, why 4GLs seem so strange, and how a programmer can increase their productivity by 2,000% (some restrictions apply).
Episode 170 - Thoroughbred/OS 10.11.2025 1:00:00
I'm back to normal episodes, and I'm running out the gate with a weird one. Thoroughbred/OS was a multi-user and multi-tasking operating system for the IBM PC. It's mian interface was... BASIC of all things! What exactly is this oddity? https://winworldpc.com/product/thoroughbred-os/662 - Try Out Thoroughbred/OS yourself
Episode 169.5 - Ben Zotto and the Story of Sphere Computers 01.11.2025 52:41
I recently had the chance to talk to Ben Zotto about his upcoming book: Go Computer Now! - The Story of Sphere Computers. It's all about an obscure machine powered by the Motorola 6800 that released in 1975. I figured it was the perfect faire for my audience. And... I really want to read this book! You can back the project over at kickstarter: http://kickstarter.com/projects/bzotto/go-computer-now...
Episode 169 - Dellinger's Viruses 26.10.2025 26:10
In 1981 Joe Dellinger attempted to create the perfect computer program: a virus that spread silently. In 1982 a revision of that virus broke containment. It would have remained completely hidden if it wasn't for an obscure Apple II game. Today we look at the story and motivation behind that virus, and how it slipped into the sands of time. Or... did it!? The truth is if you have an Apple II it may...
Episode 168 - Halt and Catch Fire 19.10.2025 26:45
Imagine a secret number that could be used to bring your computer to a screeching halt. In 1977 Gerry Wheeler discovered an interesting feature of Motorola's new 6800 microprocessor. There was a secret instruction that, if read, would cause the processor to stop working. He called this magic number Halt and Catch Fire, or HCF, and wrote a neat article about the operation. This was the first time t...
Episode 167 - The Tape That Unwound Itself 12.10.2025 27:25
Have you ever had a computer do something you can't explain? Have you ever thought a machine had a mind of its own? In 1971 Met Life was faced with this exact conundrum. Their tape drives, for some reason, were throwing tape all over the floor every night. Systems were checked and no flaws were found, but every morning an operator would walk in on an absolute mess. What could make a healthy machin...
Episode 166 - Beyond the PDP-11 05.10.2025 1:00:10
My trilogy on the PDP-11 concludes with a look at the far flung places this computer can take us. In this episode we look at some issues with claims of the PDP-11's linage, smuggling, Hungarian-made microcode, and much more. Along the way we answer the question: if the PDP-11 was such a good design then where was it during the home computing boom of the 80s?
Episode 165 - LSI-11 21.09.2025 54:48
This episode we continue my series on the PDP-11 by examining how DEC adapted to the advent of the microprocessor. Along the way we will see how the PDP-11 inspired new generations of computers, and the surprising connection to early digital hobbyists.
Episode 164 - LGP-30 LIVE! from VCF West 07.09.2025 52:03
Last weekend I had the chance to talk about the LGP-30 and my emulation project at VCF West in Mountain View, CA. The showrunners will be posting a full video later, but that takes a while to go live. In the meantime, here's the audio I siphoned off the sound board and my slide deck. View my slides here: https://drive.google.com/file/d/1E9-B3EzxudFWX0yJMevbbIkD2qRbBKWi/view?usp=sharing View the em...
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