Altair Front Panel Tutorials

If you aren’t old enough to remember when computers had front panels, as [Patrick Jackson] found out after he built a replica Altair 8800, their operation can be a bit inscrutable. After figuring it out he made a pair of videos showing the basics, and then progressing to a program to add two numbers.

Even when the Altair was new, the days of front panels were numbered. Cheap terminals were on their way and MITS soon released a “turnkey” system that didn’t have a front panel. But anyone who had used a minicomputer from the late 1960s or early 1970s really thought you needed a front panel.

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ESP32 Altair Emulator Gets Split Personality

If you wanted me to demo CP/M running on an emulated Altair 8800, I’d pull out a tiny board from my pocket. You might wonder how I wound up with an Altair 8800 that runs CP/M (even WordStar), that fits in your pocket and cost less than $10. Turns out it’s a story that goes back to 1975.

When the Altair 8800 arrived back in 1975, I wanted one. Badly. I’d been reading about computers but had no hands-on experience. But back then, as far as I was concerned, the $400 price tag might as well have been a million bucks. I was working for no real pay in my family’s store, though in all fairness, adjusted into today’s money that was about $2,000.

I’d love to buy one now, but a real Altair costs even more today than it did back then. They also take up a lot of desk space. Sure, there are replicas and I’ve had a few. I even helped work the kinks out of Vince Briel’s clone which I’ve enjoyed. However, the Briel computer has two problems. First, it takes a little work to drive a serial port (it uses a VGA and a PS/2 keyboard). Second, while it’s smaller than a real Altair, it is still pretty large — a byproduct of its beautiful front panel.

So to quickly show off CP/M to someone, you need to haul out a big box and find a VGA monitor and PS/2 keyboard — both of which are becoming vanishing commodities. I made some modifications to get the serial port working, but it is still a lot to cart around. You could go the software route with a simulator like SIMH or Z80pack, but now instead of finding a VGA monitor and a PS/2 keyboard, you need to find a computer where you can install the software. What I really wanted was a simple and portable device that could boot CP/M.

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Altair 8800 Again Project

[Dirk] posted a video (you can see below) titled, “Mystery Retro Project Start.” That turned out to be the first of a multipart series on his Altair 8800 Again simulator. The front panel appears to be laser cut and in some future video episodes, we expect to see him simulate the CPU with a Teensy.

There have been plenty of 8800 clones ranging from projects that recreate the original PCBs, to those that just run a Raspberry Pi inside. The middle ground will use an Arduino or some other small CPU to simulate the 8080 CPU.

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Prolific Videos Show Altair 8800 Recreation

The January 1975 issue of Popular Electronics introduced the Altair 8800 and hit the newsstands in December of 1974, so it is only natural that around the New Year people start thinking about the old computer. [Shadowtron] did more than think about it. He ordered some replica PCBs and is building a new one. Even better, he’s posted an amazing number of videos (up to number 56 as I write this) detailing his progress. You can find part 1, below.

The boards are from Trailing Edge Technology. There’s a backplane board (about $100) as well as a few boards to fit it available for about $30 each — unpopulated, of course.

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Emulating An Altair 8800 On An Apple II

The Altair 8800 was, to its creators, a surprise hit. Despite looking nothing like what we would today consider to be a computer, it sold thousands of units almost immediately upon its launch, way back in 1975. A few years later, the Apple II burst onto the scene, and the home computer revolution began in earnest.

Emulating older machines on newer hardware has always been a thing, and [option8] has coded an Altair 8800 emulator for the Apple II. Of course, if you don’t have one lying around, you can run this emulator on an Apple II emulator right in your browser. Honestly, it’s emulators all the way down.

As far as emulators go, this is a particularly charming one, with the Altair’s front panel displayed in glorious color on the Apple’s 40 column screen. Replete with a full set of switches and blinking LEDs, it’s a tidy low-resolution replica of the real thing. Instructions to drive it are available, along with those for another similar emulator known as Apple80.

If that still hasn’t quenched your thirst, check out this Game Boy emulator that lives inside emacs.

Programmable Ruler Keeps 1970’s Computing Alive

A ruler seems like a pretty simple device; just a nice straight piece of material with some marks on it. There are some improvements out there to the basic design, like making it out of something flexible or printing a few useful crib notes and formulas on it so you have a handy reference. But for the most part, we can all agree that ruler technology has pretty much plateaued.

Well, not if [Brad] has anything to say about it. His latest creation, the Digirule2, is essentially an 8-bit computer like those of the 1970’s that just so happens to be a functional ruler as well. Forget lugging out the Altair 8800 next time you’re in the mood for some old school software development, now you can get the same experience with a piece of hardware that lives in your pencil cup.

Even if you’ve never commanded one of the blinkenlight behemoths that inspired the Digirule2, this is an excellent way to get some hands-on experience with early computer technology. Available for about the cost of a large pizza on Tindie, it represents one of the easiest and most cost-effective ways to tell your friends that as a matter of fact you have programmed a computer in binary.

The Digirule2 is powered by a Microchip PIC18F43K20, and is programmed by punching binary in one byte at a time with a bank of eight tactile switches. To make things a little easier, programs can be saved to the internal EEPROM and loaded back up just as easily thanks to the handy buttons next to the power switch. Now all you’ve got to do is figure out what all those blinking LEDs mean, and you’ll be in business.

The original Digirule was a logic gate simulator that we first covered back in 2015. We’re always happy to see projects grow and evolve over time, and think this new retro-computer themed variant is going to be quite popular with those who still love toggle switches and blinking lights.

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IMSAI 8080 Resurrection

When MITS introduced the Altair 8800–about 43 years ago–it spawned the first personal computer clone: the IMSAI 8080. The clone had several improvements and MITS had difficulty filling orders for real Altairs, so they sold pretty well. [IMSAI Guy] has one of these vintage computers that has been in storage for over 30 years. He’s restoring the thing and there are 26 (and counting) videos of his progress. You can see the second video below, but be sure to check out the others, too.

The IMSAI is famous for being in the movie Wargames. We miss computers with switches and LEDs on a working front panel.

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