The Modding, Restoration, And Demise Of A $3M Analog Computer

February 9, 2021 by Chris Lott 24 Comments

How do you rapidly record the output from your three million dollar analog computer in the 1940s when the results are only available on analog meters? The team responsible for the Westinghouse 1947 AC Network Calculator at Georgia Tech was faced with just this problem and came up with a nifty solution — hack the control panel and wire in a special-purpose drafting table.

What Is It?

What is this beast of a computer? Machines of this type were developed during and after World War 2, and strictly speaking, belong in the category of scale models rather than true computers. Although these machines were very flexible, they were primarily designed to simulate power distribution grids. There is a lot of theory under the hood, but basically a real world, multi-phase distribution system would be scaled to single-phase at 400 Hz for modeling.

The engineers would “program” the machine by connecting together the appropriate circuit elements (like capacitors, inductors, transmission lines, generators, etc.) on big patch panels. Thus programmed, a 10 kW motor-generator located in the basement would be started up and the simulation was underway. Continue reading “The Modding, Restoration, And Demise Of A $3M Analog Computer” →

All The Good VR Ideas Were Dreamt Up In The 60s

January 4, 2021 by Donald Papp 39 Comments

Virtual reality has seen enormous progress in the past few years. Given its recent surges in development, it may come as a bit of a surprise to learn that the ideas underpinning what we now call VR were laid way back in the 60s. Not all of the imagined possibilities have come to pass, but we’ve learned plenty about what is (and isn’t) important for a compelling VR experience, and gained insights as to what might happen next.

If virtual reality’s best ideas came from the 60s, what were they, and how did they turn out?

Interaction and Simulation

First, I want to briefly cover two important precursors to what we think of as VR: interaction and simulation. Prior to the 1960s, state of the art examples for both were the Link Trainer and Sensorama.

The Link Trainer was an early kind of flight simulator, and its goal was to deliver realistic instrumentation and force feedback on aircraft flight controls. This allowed a student to safely gain an understanding of different flying conditions, despite not actually experiencing them. The Link Trainer did not simulate any other part of the flying experience, but its success showed how feedback and interactivity — even if artificial and limited in nature — could allow a person to gain a “feel” for forces that were not actually present.

Sensorama was a specialized pod that played short films in stereoscopic 3D while synchronized to fans, odor emitters, a motorized chair, and stereo sound. It was a serious effort at engaging a user’s senses in a way intended to simulate an environment. But being a pre-recorded experience, it was passive in nature, with no interactive elements.

Combining interaction with simulation effectively had to wait until the 60s, when the digital revolution and computers provided the right tools.

The Ultimate Display

In 1965 Ivan Sutherland, a computer scientist, authored an essay entitled The Ultimate Display (PDF) in which he laid out ideas far beyond what was possible with the technology of the time. One might expect The Ultimate Display to be a long document. It is not. It is barely two pages, and most of the first page is musings on burgeoning interactive computer input methods of the 60s.

The second part is where it gets interesting, as Sutherland shares the future he sees for computer-controlled output devices and describes an ideal “kinesthetic display” that served as many senses as possible. Sutherland saw the potential for computers to simulate ideas and output not just visual information, but to produce meaningful sound and touch output as well, all while accepting and incorporating a user’s input in a self-modifying feedback loop. This was forward-thinking stuff; recall that when this document was written, computers weren’t even generating meaningful sounds of any real complexity, let alone visual displays capable of arbitrary content. Continue reading “All The Good VR Ideas Were Dreamt Up In The 60s” →

Printed Circuits, 1940s Style

December 8, 2020 by Chris Lott 35 Comments

A presentation this month by the Antique Wireless Museum brought British engineer and inventor John Sargrove (1906-1974) to our attention. If you’ve ever peeked inside old electronics from days gone by, you’ve no doubt seen point-to-point wiring and turret board construction. In the 60s and 70s these techniques eventually made way for printed circuit boards which we still use today. But Mr Sargrove was way ahead of his time, having already invented a process in the 1930s to print circuits, not just boards, onto Bakelite. After being interrupted by the war, he formed a company Electronic Circuit Making Equipment (ECME) and was building broadcast radio receivers on an impressive automatic production line.

Mr. Sargrove’s passion was making radios affordable for everyone. But to achieve this goal, he had to make large advances manufacturing technology. His technique of embedding not only circuit traces, but basic circuit elements like resistors, capacitors, and inductors directly into the substrate foresaw techniques being applied decades later in integrated circuit design. He also developed a compact vacuum tube which could be used in all circuits of a radio, called an “All-stage Valve“. Equally important was his futuristic automatic factory, which significantly reduced the number of factory workers needed to make radios from 1500 to 50. Having completed the radio design, he was also developing a television receiver using the same concepts. Unfortunately, ECME was forced into liquidation when a large order from India was cancelled upon declaration of independence in 1947.

You really must watch the video below. There are many bits and pieces of modern factory automation which we still use today, yet their implementation using 1940s techniques and technology is fascinating. Further reading links after the video. Thanks to [Mark Erdle] for the tip.

Continue reading “Printed Circuits, 1940s Style” →

Celebrating The 4004’s 0x31st Anniversary

November 16, 2020 by Chris Lott 5 Comments

This weekend marked the 49th anniversary of the legendary Intel 4004 microprocessor, and to celebrate [Erturk Kocalar] combined the old and new in this intriguing Retroshield 4004 / Busicom 141-PF calculator project. We have reported on his Arduino shield project before, which lets you connect a variety of old microprocessors to an Arduino so you can experiment with these old chips with a minimum of fuss.

[Erturk] decided to use the Arduino to simulate the hardware of the Busicom 141-PF, a calculator famous for bringing us the microprocessor. In addition to the calculator, the Arduino has to simulate the Intel 4004 CPU’s supporting chips, which include ROM, RAM, and shift registers. If you want to build one of these yourself, all the design files are open source, or you can get an assembled shield from his Tindie store. In either case, you will have to provide your own 4004, which are surprisingly still available. (Tindie and Hackaday share the same parent company, Supplyframe. We’ve got nothing to do with Intel.)

We really appreciate the detailed explanation that [Erturk] provides about the inner workings of the calculator. Interfacing the emulator to the original ROM code running on the 4004 is non-trivial — take a look at the explanation of the spinning drum printer, for example. We enjoyed perusing the annotated ROM listing, as well as reading the story of the efforts which have been undertaken to prevent these historical documents from being lost forever. Be sure to check out the history of the 4004 and its inventor Federico Faggin if you’d like to delve deeper.

Tracking Satellites With A Commodore PET

October 29, 2020 by Chris Lott 16 Comments

A recent writeup by Tom Nardi about using the 6502-based NES to track satellites brought back memories of my senior project at Georgia Tech back in the early 80s. At our club station W4AQL, I had become interested in Amateur Radio satellites. It was quite a thrill to hear your signal returning from space, adjusting for Doppler as it speeds overhead, keeping the antennas pointed, all while carrying on a brief conversation with other Earth stations or copying spacecraft telemetry, usually in Morse code.

Continue reading “Tracking Satellites With A Commodore PET” →

Flash Is Dead, But Its Culture Should Live On

October 24, 2020 by Erin Pinheiro 46 Comments

Flash is all but gone already, but as we approach the official Adobe end-of-life date on December 31st, it’s picking up traction one last time as people reminisce about the days of Internet past. Back in July, [Jonas Richner] created an impressive website that catalogs not only almost 20 years of Flash games, but also testimonials for the software from dozens of developers who began their careers with it.

Flash started in 1996 with the intention of being a standard for animations and vector graphics on the early Web. With the release of Flash Player 5 in August of 2000, Macromedia (later acquired by Adobe) presented the first version of ActionScript, an object-oriented scripting language meant to bring interactivity to animated Flash movies. Since then, thousands of games made with the platform were released online through websites like Newgrounds and shared all over the world, with the most popular games easily reaching tens of millions of plays.

These games became popular in part thanks to how quickly they could be created with the Flash authoring tools, but also because it was so easy for players to run them. With a single plugin for your web browser of choice, the barrier of entry was extremely low. Most home computers from the mid-2000s were able to run Flash software without needing dedicated graphics hardware. This prompted a “creative chaos” as [Richner] puts it, spawning millions of games and animations which started genres and careers lasting to this day.

Unfortunately, browsers have been dropping support for the plugin due to vulnerabilities in the most recent iterations of its scripting engine and Google no longer indexes Flash files. It would seem this particularly creative era of the Internet is coming to an end. However, you can still relive old games and animations made with plugins such as Flash and Shockwave with [BlueMaxima]’s Flashpoint, and like [Richner], we also hope that the people building today’s platforms and technologies keep the lessons from Flash in mind.

Start Me Up: What Has The Windows 95 Desktop Given Us 25 Years Later?

August 31, 2020 by Jenny List 104 Comments

We’ve had something of an anniversary of late, and it’s one that will no doubt elicit a variety of reactions from our community. It’s now 25 years ago that Windows 95 was launched, the operating system that gave the majority of 1990s PC users their first taste of a desktop-based GUI and a 32-bit operating system.

To the strains of the Rolling Stones’ Start me up, Microsoft execs including Bill Gates himself jubilantly danced on stage at the launch of what was probably to become the company’s defining product, perhaps oblivious to the line “You make a grown man cry” which maybe unwittingly strayed close to the user experience when faced with some of the software’s shortcomings.

Its security may seem laughable by the standards of today and the uneasy marriage of 16-bit DOS underpinning a 32-bit Windows operating system was clunky even in its heyday, but perhaps now is the best time to evaluate it unclouded by technical prejudice. What can we see of Windows 95 in the operating systems we use today, and thus from that can we ask the question: What did Windows 95 get right? Continue reading “Start Me Up: What Has The Windows 95 Desktop Given Us 25 Years Later?” →