Arctic Adventures With A Data General Nova II — The Equipment

February 5, 2024 by Chris Lott 51 Comments

As I walked into the huge high bay that was to be my part-time office for the next couple of years, I was greeted by all manner of abandoned equipment haphazardly scattered around the room. As I later learned, this place was a graveyard for old research projects, cast aside to be later gutted for parts or forgotten entirely. This was my first day on the job as a co-op student at the Georgia Tech Engineering Experiment Station (EES, since renamed to GTRI). The engineer who gave me the orientation tour that day pointed to a dusty electronic rack in one corner of the room. Steve said my job would be to bring that old minicomputer back to life. Once running, I would operate it as directed by the radar researchers and scientists in our group. Thus began a journey that resulted in an Arctic adventure two years later.

The Equipment

The computer in question was a Data General (DG) mini computer. DG was founded by former Digital Equipment Corporation (DEC) employees in the 1960s. They introduced the 16-bit Nova computer in 1969 to compete with DEC’s PDP-8. I was gawking at a fully-equipped Nova 2 system which had been introduced in 1975. This machine and its accessories occupied two full racks, with an adjacent printer and a table with a terminal and pen plotter. There was little to no documentation. Just to turn it on, I had to pester engineers until I found one who could teach me the necessary front-panel switch incantation to boot it up. Continue reading “Arctic Adventures With A Data General Nova II — The Equipment” →

How Much Longer Will Cars Have Cigarette Lighter Ports?

February 1, 2024 by Kristina Panos 106 Comments

Depending on the age of your car, it might contain a round 12 V power outlet in the dash, or possibly in the elbow compartment. And depending on your own age, you might know that as the cigarette lighter port. Whereas this thing used to have a single purpose — lighting cigars and cigarettes via hot coil — there are myriad uses today, from charging a phone to powering a dash camera to running one of those tire-inflating machines in a roadside emergency.

But how did it come to be a power source inside the vehicle? And how long will it stick around? With smoking on the decline for several decades, fewer and fewer people have the need for a cigarette lighter than do, say, a way to charge their phone. How long will the power source survive in this configuration?

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The Cockpit Voice Recorder Controversy

January 31, 2024 by Lewin Day 75 Comments

Every time there’s a plane crash or other aviation safety incident, we often hear talk of the famous “black box”. Of course, anyone these days will tell you that they’re not black, but orange, for visibility’s sake. Plus, there’s often not one black box, but two! There’s a Flight Data Recorder (FDR), charged with recording aircraft telemetry, and a Cockpit Voice Recorder (CVR), designed to record what’s going on in the cabin.

It sounds straightforward enough, but the cockpit voice recorder has actually become the subject of some controversy in recent times. Let’s talk about the basics of these important safety devices, and why they’re the subject of some debate at the present time.

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The World’s First Microprocessor: F-14 Central Air Data Computer

January 30, 2024 by Maya Posch 34 Comments

When the Grumman F-14 Tomcat first flew in 1970, it was a marvel. With its variable-sweep wing, twin tail, and sleek lines, it quickly became one of the most iconic jet fighters of the era — and that was before a little movie called Top Gun hit theaters.

A recent video by [Alexander the ok] details something that was far less well-documented about the plane, namely its avionics. The Tomcat was the first aircraft to use a microprocessor-driven flight system, as well as the first microprocessor unit (MPU) ever demonstrated, beating the Intel 4004 by a year. In 1971, one of the designers of the F-14’s Central Air Data Computer (CADC) – [Ray Holt] – wrote an article for Computer Design magazine that was naturally immediately classified by the Navy until released to the public in 1998.

The MPU in the CADC is called the Garrett AiResearch MP944, and consists of a number of ICs that together form a full computer. These were combined in the CADC with additional electronics to control many elements of the airplane automatically, including the weapons system and the variable-sweep wing configuration. This was considered to be essential based on experiences with the F-111 and its very complex electromechanical flight computer, which was an evolution of the 1950s-era Bendix CADC.

The video goes through the differences between the 4-bit Intel 4004 and the 20-bit MP944, questioning whether the 4004 is even really an MPU, the capabilities of the MP944 and its system architecture. Ultimately the question of ‘first’ and that of ‘what is an MPU’ will always be somewhat fuzzy depending on your definitions, but there is no denying that the MP944 was a marvel of large-scale integration.

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The Past, Present, And Future Of Inflatable Space Habitats

January 30, 2024 by Tom Nardi 24 Comments

Recently, a prototype inflatable space station module built by Sierra Space exploded violently on a test stand at NASA’s Marshall Space Flight Center in Alabama. Under normal circumstances, this would be a bad thing. But in this case, Sierra was looking forward to blowing up their handiwork. In fact, there was some disappointment when it failed to explode during a previous test run.

That’s because the team at Sierra was looking to find the ultimate bust pressure of their 8.2 meter (26.9 foot) diameter Large Integrated Flexible Environment (LIFE) module — a real-world demonstration of just how much air could be pumped into the expanding structure before it buckled. NASA recommended they shoot for just under 61 PSI, which would be four times the expected operational pressure for a crewed habitat module.

By the time the full-scale LIFE prototype ripped itself apart, it had an internal pressure of 77 PSI. The results so far seem extremely promising, but Sierra will need to repeat the test at least two more times to be sure their materials and construction techniques can withstand the rigors of spaceflight.

Sierra is a targeting no earlier than 2026 for an in-space test, but even if they nail the date (always a dubious prospect for cutting edge aerospace projects), they’ll still be about 20 years late to the party. Despite how futuristic the idea of inflatable space stations may seem, NASA first started experimenting with the concept of expandable habitat modules back in the 1990s, and there were practical examples being launched into orbit by the early 2000s.

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Tech In Plain Sight: Escalators

January 29, 2024 by Al Williams 36 Comments

If you are designing a building and need to move many people up or down, you probably will at least consider an escalator. In fact, if you visit most large airports these days, they even use a similar system to move people without changing their altitude. We aren’t sure why the name “slidewalk” never caught on, but they have a similar mechanism to an escalator. Like most things, we don’t think much about them until they don’t work. But they’ve been around a long time and are great examples of simple technology we use so often that it has become invisible.

Of course, there’s always the elevator. However, the elevator can only service one floor at a time, and everyone else has to wait. Plus, a broken elevator is useless, while a broken escalator is — for most failures — just stairs.

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Roman Dodecahedrons: A Mystifying Archaeological Find

January 29, 2024 by Maya Posch 121 Comments

Much about archaeology can be described as trying to figure out the context in which objects and constructions should be interpreted. A good example of this are the metal dodecahedrons (twelve-sided shape) which have been found during archaeological excavations at former Roman sites. Since 1739 over 115 of them have been recorded, most recently a fully intact copper specimen found near the Lincolnshire village of Norton Disney during the Summer of 2023 by a local group of archaeologists.

Two ancient Roman bronze dodecahedrons and an icosahedron (3rd c. AD) in the Rheinisches Landesmuseum in Bonn, Germany. (Credit: Kleon3, Wikimedia)

As the Norton Disney History and Archaeology Group notes on their page, this is the 33rd example of one of these items found in what was once Roman Britain, lending credence to the idea that such dodecahedrons originated within the Gallo-Roman culture.

As for the objects themselves, the ones so far found were dated to between the 2nd and 4th century CE, are all made out of some kind of metal alloy (e.g. bronze), are usually a dodecahedron but sometimes different (e.g. an icosahedron with 20 faces), yet all are hollow and usually with a single large hole in each face. The dodecahedron found at Norton Disney was analyzed to consist out of 75% copper, 7% tin and 18% lead, with a width of 8.6 cm and weighing in at 254 grams.

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