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? Selected Sources: Zeroth Generation by George Stibitz (NOW WITH A 2nd EDITION!) http://www.bitsavers...
Jan 12, 2026•1 hr 3 min•Ep. 174
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 like what you would expect.
Dec 29, 2025•1 hr 3 min•Ep. 173
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 digital machines: the analogs. Eventually the two technologies would merge in an attempt to create the...
Dec 15, 2025•1 hr 5 min•Ep. 172
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).
Nov 24, 2025•55 min•Ep. 171
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
Nov 10, 2025•1 hr•Ep. 170
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-the-story-of-sphere?ref=ey52pt And find out more at Ben's sites: https://gocomputernow.com/, https:...
Nov 01, 2025•53 min
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 be infected with Dellinger's virus! My main source: https://virus.wdfiles.com/local--files/applvir/...
Oct 26, 2025•26 min•Ep. 169
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 the public would learn about the secret powers of HCF, but this isn't actually the beginning of the s...
Oct 19, 2025•27 min•Ep. 168
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 machine spit up it's precious tape?
Oct 12, 2025•27 min•Ep. 167
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?
Oct 05, 2025•1 hr•Ep. 166
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.
Sep 21, 2025•55 min•Ep. 165
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 emulator at: https://lgp30.org...
Sep 07, 2025•52 min•Ep. 164
The DEC PDP-11 is one of the most influential minicomputers of all time. Some would even call it the most influential computer of all time. But where exactly did it come from? How was it designed? This episode is the start of a 3 part series that will look at how the PDP-11 was created, adapted to changes, and the strange places it ended up.
Aug 24, 2025•58 min•Ep. 163
In 1949 CSIRAC sprung to life in a lab in Sydney, Australia. It was a very early stored program computer. All machines of the era were unique. But CSIRAC, well, it was very unique indeed. Selected Sources: https://cis.unimelb.edu.au/about/csirac/music/reconstruction - The Music of CSIRAC https://sci-hub.se/10.1109/MAHC.1984.10014 - Pearcy and Beard on CSIRAC...
Aug 10, 2025•1 hr 1 min•Ep. 162
The first batch of digital computers emerge directly following WWII. The hallmark of this generation is uniqueness: no two computers are the same. However, there is a machine that bucks that trend. The IAS Machine, built in Princeton in the late 1940s, served as the inspiration for at least a dozen later computers. But how similar were these Princeton-class computers? What exactly was so special about the IAS Machine? And how does good 'ol Johnny von Neumann get tied up in all of this? The Easte...
Jul 13, 2025•1 hr 3 min•Ep. 161
Lunar Lander is one of the best loves video games of all time. The game was created in 1969 as an homage to the recent Apollo 11. From there it would only spread. Just about anything that can print text has it's own version of Lunar Lander. The early history of this game is mixed up with something weird: two nearly identical programming languages. Today we will be using the history of Lunar Lander as a good excuse to look at an obscure tongue called FOCAL. This language is so close to BASIC that...
Jun 29, 2025•56 min•Ep. 160
In 1982 Intel released the iAPX 286. It's was the first heir to the smash-hit 8086. But the 286 was developed before the IBM PC put an Intel chip on every desk. It's design isn't influence by the PC. Rather, it reaches further into the past. Today we are looking at the strange melding of old technology, new ideas, and compatibility that lead to the 286.
Jun 15, 2025•1 hr 7 min•Ep. 159
In 1973 the world caught it's first glimpse of INTERCAL. It's a wild and wacky language, somewhere between comedy and cutting satire. But the compiler was never circulated. There would be later implementations, but that original compiler remained lost to time. That is, until now. This episode covers how the original source code was found, and my attempt to get it up and running. Get the source code for INTERCAL72 here: https://github.com/rottytooth/INTERCAL72/ Read the original INTERCAL manual: ...
Jun 01, 2025•1 hr 8 min•Ep. 158
The S1 operating system can do it all! It can run on any computer, read any disk, and execute any software. It can be UNIX compatible, DOS compatible, and so, so much more! But... can S1 ship? Today we are talking about an operating system that sounds too good to be true. Is it another example of vaporware? Or is S1 really the world's most sophisticated operating system?
May 11, 2025•1 hr 5 min•Ep. 157
How do you make a computer act less like a computer? It sounds like some kind of riddle, but in the early 1960s it was an actual problem. As IBM customers transitioned from tabulators to computers they ran into all sorts of practical issues. Programmers became a hot commodity. But how do you find a programmer in 1959? And how can you even afford such a luxury? Wouldn't it be better if you could just use your new computer as a tabulator? Well, with RPG, all that and more was possible.
Apr 27, 2025•1 hr 4 min•Ep. 156
In the early 1960s a neat little machine came out of MIT. Well, kind of MIT. The machine was called LINC. It was small, flexible, and designed to live in laboratories. Some have called it the first personal computer. But, is that true? Does it have some secret that will unseat my beloved LGP-30? And how does DEC fit into the picture?
Apr 13, 2025•58 min•Ep. 155
The LGP-30 is one of my favorite computers. It's small, scrappy, strange, and wonderous. Among its many wonders are two obscure languages: ACT-I and ACT-III. In this episode we are exploring the ACTS, how the LGP-30 was programmed in practice, and why I've been losing sleep for the last few weeks.
Mar 30, 2025•1 hr 21 min•Ep. 154
When I was down at VCF SoCal I ran into a strange machine: the Keypact Micro-VIP. It's a terminal without a keyboard, covered in dials, with a speaker and a switch labeled "voice". This chance encounter with the unknown sent me down a wild path. It involved the creeping spread of computing, chicken feed, door to door life insurance salesmen, and at least one early hacker.
Mar 17, 2025•55 min•Ep. 153
A special treat from VCF SoCal. While visiting I had the chance to host a panel on restoration and preservation. I was joined by: David from Usagi Electric ( https://www.youtube.com/@UsagiElectric) Rob from Souther Amis ( https://www.southernamis.com/) Jim, Former Executive Director Computer Museum of America ( https://computerhalloffame.org/home/about/)...
Mar 02, 2025•1 hr•Ep. 152
Have you ever looked at an old computer and seen a weird typewriter thing tacked on? In most cases that's a device called a Flexowriter. It's half electric typewriter, half teleprinter, half tape reader, and all business! This episode we are chronicling the rise, fall, and weird business dealings of the Flexowriter.
Feb 03, 2025•1 hr 1 min•Ep. 151
In the modern day Windows is a power house, but that wasn't always the case. In this episode we are looking at the fraught development of Windows 1.0. During development it was called vaporware, it was panned in the press, roasted at at least one trade show, and even called... "eclectic". Through it all a vision in lime green would take form.
Jan 20, 2025•1 hr 5 min•Ep. 150
This episode we are taking a trip back to UNIX world. We're looking at IDRIS, the first clone of UNIX. It was supposed to be highly compatible, but use no code from Bell Labs. IDRIS ran on everything from the Intel 8080 up to the IBM System/370. There was even a version that could run MS-DOS programs. Sound too good to be true? Well, that may be the case. Selected Sources: https://archive.org/details/aquartercenturyofunixpeterh.salus_201910/page/n196/mode/1up - A Quarter Century of UNIX https://...
Jan 05, 2025•59 min•Ep. 149
In 1970 a little language called BLISS emerged from Carnegie Mellon University. It was a systems language, meant for operating systems and compilers. It was designed, in part, as a response to Dijkstra's famous Go To Considered Harmful paper. It had no data types. It used the most bizzare form of the pointer I've ever seen. And it was a direct competitor to C. Sound interesting, yet? Selected Sources: https://bitsavers.computerhistory.org/pdf/dec/decus/pdp10/DECUS-10-118-PartII_BlissReadings_Dec...
Dec 22, 2024•1 hr 3 min•Ep. 148
In 1961 Texas Instruments unveiled the Molecular Electronic Computer, aka: Mol-E-Com. It was a machine that fit in the palm of your hand, but had all the power of a much larger computer. This was in an age of hefty machines, which made the achievement all the more marvelous. How was this even possible? It was all thanks to the wonders of molecular electronics, and a boat load of funding from the US Air Force. Selected Sources: https://web.archive.org/web/20160304071831/http://corphist.computerhi...
Dec 09, 2024•55 min•Ep. 127
The Z4, completed by Konrad Zuse in 1945, is a computer with a wild story. It was made from scrounged parts, survived years of bombing raids, moved all around Berlin, and eventually took refuge in basements and stables. In this episode we will follow the Z4's early days, and look at how it fits into the larger picture of Zuse's work. Along the way there is looting, rumors, and even... IBM! Selected Sources: The Computer, My Life - Konrad Zuse's autobiography https://web.archive.org/web/200902200...
Nov 25, 2024•58 min•Ep. 146
