Retrotechtacular: Here’s How They Programmed The EDSAC Computer

September 28, 2018 by Jenny List 4 Comments

When you write a program for your computer, whether it is a desktop machine, a microcontroller, or a supercomputer, the chances are that you use software tools to help you get the job done. High level languages, compilers, linkers, assemblers, debuggers, and code libraries have become so integrated that in many cases you will barely be aware of their existence. To all intents and purposes this huge toolchain will be the computer. But the first computer programmers had none of these luxuries. They had to hand assemble their own binaries, check them by hand, and debug them by guessing what had happened when they failed.

EDSAC I, 1948, W.Renwick with 5 hole tape reader and Creed teleprinter. Copyright Computer Laboratory, University of Cambridge. Reproduced by permission. [CC BY 2.0 UK]

EDSAC (Electronic delay storage automatic calculator) was the first computer operated by the University of Cambridge in the UK and one of the first few computers in the entire world when it was built in the late 1940s. It is the subject of the 1951 film you’ll find embedded below. Originally produced for a conference, the video sports a 1976 introduction and narration from the machine’s creator Professor Maurice Wilkes. It doesn’t take us through the design of the machine itself, instead it concentrates on the workflow required to program it.

The Paper-Heavy Process of Programming EDSAC

To illustrate the programming process, a committee of people who would now call themselves computer scientists, but probably then called themselves mathematicians, breaking a formula into subroutines before the code is laboriously hand assembled. The linking process is performed manually too by the secretary who types the code into a teletype for transfer to a punched tape. When a library function is required she reaches into a filing cabinet for the roll of tape containing it before running it through a tape duplicator to add it to the program. Finally the completed tape is checked and added to a job queue that consists of a row of hooks on the wall. Never complain that your toolchain is unwieldy again!

The original EDSAC was decommissioned in the late 1950s after serving the university and spawning a commercial version, the LEO, which became the first ever computer manufactured for use in commerce. That was not the end of the EDSAC story though, because in this century a team at the National Museum of Computing at Bletchley Park set about recreating EDSAC as an exhibit. And as luck would have it a member of that team was at the recent Electromagnetic Field hacker camp to give a talk about their work which you will also find below.

Building a Faithful Reproduction of EDSAC

Tony Abbey gives us both a history of the machine and a description of its architecture, followed by a run through their efforts in rebuilding it. You may be surprised by some of the unexpected facts from the talk. For instance, while all the tubes used in the EDSAC are still available, their bases are not. Equivalents were sourced from China, but team members had to modify them with dental drills.

They also needed to manufact the 1940s-style tube chassis, and the solution to that problem happened to be just down the road. Bletchley is part of modern-day Milton Keynes, a post-war new town that is also home to another famous name: Marshall amplifiers. Tube amps are built in a surprisingly similar way, so they took on the manufactured challenge. Not all the parts of the new EDSAC are original though. The memory used mercury delay lines in 1949, but for 2018 recreation the computer has a delay line using nickel wire and modern components. Tony admits that even that has caused problems, and there is a simulator using a microcontroller.

You can see the restored EDSAC at the National Museum of Computing. We visited it in 2016, and you can read our review. Meanwhile if you are an FPGA wizard, you can even have a virtual EDSAC of your own.

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Retrotechtacular: The Iron Giants That Built The Jet Age

September 1, 2018 by Dan Maloney 45 Comments

In the closing months of World War II, the Axis and the Allies were throwing everything they had at each other. The tide was turning to the Allies’ favor, but the Germans were showing a surprising resilience, at least in terms of replacing downed fighter and bomber aircraft. When the Allies examined the wreckage of these planes, they discovered the disturbing truth: the planes contained large pieces forged from single billets of metal, which suggested a manufacturing capability none of the Allies possessed and which allowed the Germans to quickly and cheaply make better and faster planes.

When the war was over, the Allies went looking for the tools the Germans had used to make their planes, and found massive closed-die forging presses that could squeeze parts out of aluminum and magnesium alloys in a single step. The Soviets carted off a 30,000 ton machine, while the Americans went home with a shipload of smaller presses and the knowledge that the Russians had an edge over them. Thus began the Heavy Press Program, an ultimately successful attempt by the US military to close a huge gap in strategic manufacturing capabilities that [Machine Thinking] details in the excellent video below.

One doesn’t instantly equate monstrous machines such as the Mesta 50,000-ton press, over nine stories tall with half of it buried underground and attached directly to bedrock, with airplane manufacture. But without it and similar machines that came from the program, planes from the B-52 to the Boeing 747 would have been impossible to build. And this isn’t dead technology by any means; sold to Alcoa in 1982 after having been operated by them for decades, the “Fifty” recently got a $100 makeover after cracks appeared in some castings, and the press and its retro-brethren are still squeezing out parts for fighters as recent as the F-35.

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Retrotechtacular: Constructing A Car Engine

July 4, 2018 by Jenny List 18 Comments

Oxford is a city world-famous for its university, and is a must-see stop on the itinerary of many a tourist to the United Kingdom. It features mediaeval architecture, unspoilt meadows, two idylic rivers, and a car plant. That’s the part the guide books don’t tell you, if you drive a BMW Mini there is every chance that it was built in a shiny new factory on the outskirts of the historic tourist destination.

A 1930s Morris Ten Series II. Humber79 [CC BY-SA 3.0].

The origins of the Mini factory lie over the road on a site that now houses a science park but was once the location of the Morris Motors plant, at one time Britain’s largest carmaker. In the 1930s they featured in a British Pathé documentary film which we’ve placed below the break, part of a series on industry in which the production of an internal combustion engine was examined in great detail. The music and narration is charmingly of its time, but the film itself is not only a fascinating look inside a factory of over eight decades ago, but also an insight into engine manufacture that remains relevant today even if the engine itself bears little resemblance to the lump in your motor today.

Morris produced a range of run-of-the-mill saloon cars in this period, and their typical power unit was one of the four-cylinder engines from the film. It’s a sidevalve design with a three-bearing crank, and it lacks innovations such as bore liners. The metallurgy and lubrication in these engines was not to the same standard as an engine of today, so a prewar Morris owner would not have expected to see the same longevity you’d expect from your daily.

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Retrotechtacular: Car Navigation Like It’s 1971

June 17, 2018 by Dan Maloney 63 Comments

Anyone old enough to have driven before the GPS era probably wonders, as we do, how anyone ever found anything. Navigation back then meant outdated paper maps, long detours because of missed turns, and the far too frequent stops at dingy gas stations for the humiliation of asking for directions. It took forever sometimes, and though we got where we were going, it always seemed like there had to be a better way.

Indeed there was, but instead of waiting for the future and a constellation of satellites to guide the way, some clever folks in the early 1970s had a go at dead reckoning systems for car navigation. The video below shows one, called Cassette Navigation, in action. It consisted of a controller mounted under the dash and a modified cassette player. Special tapes, with spoken turn-by-turn instructions recorded for a specific route, were used. Each step was separated from the next by a tone, the length of which encoded the distance the car would cover before the next step needed to be played. The controller was hooked to the speedometer cable, and when the distance traveled corresponded to the tone length, the next instruction was played. There’s a long list of problems with this method, not least of which is no choice in road tunes while using it, but given the limitations at the time, it was pretty ingenious.

Dead reckoning is better than nothing, but it’s a far cry from GPS navigation. If you’re still baffled by how that cloud of satellites points you to the nearest Waffle House at 3:00 AM, check out our GPS primer for the details.

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Retrotechtacular: Voice Controlled Robot From 1961

June 15, 2018 by Al Williams 18 Comments

We like to think that all these new voice-controlled gadgets like our cell phones, Google Home, Amazon Echo, and all that is the pinnacle of new technology. Enabled by the latest deep learning algorithms, voice-controlled hardware was the stuff of science fiction back in the 1961s, right? Not really. Turns out in around 1960, Ideal sold Robot Commando, a kid’s toy robot that featured voice control.

Well, sort of. If you look at the ad in the video below, you’ll see that a kid is causing the robot to move and fire missiles by issuing commands into a microphone. How did some toy company pull this off in 1961?

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Retrotechtacular: The Saturn Propulsion System

May 16, 2018 by Jenny List 33 Comments

“We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard; because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one we intend to win, and the others, too”

When President Kennedy gave his famous speech in September 1962, the art of creating liquid-fueled rocket engines of any significant size was still in its relative infancy. All the rocketry and power plants of the Saturn series of rockets that would power the astronauts to the Moon were breaking entirely new ground, and such an ambitious target required significant plans to be laid. What is easy to forget from a platform of five decades of elapsed time is the scale of the task set for the NASA engineers of the early 1960s.

The video below the break is from 1962, concurrent with Kennedy’s speech, and it sets out the proposed development of the succession of rocket motors that would power the various parts of the Saturn family. We arrive at the famous F-1 engine that would carry the mighty Saturn 5 and start its passengers on their trip to the Moon at a very early stage in its development, after an introduction to liquid rocket engines from the most basic of first principles. We see rockets undergoing testing on the stand at NASA’s Huntsville, Alabama facility, along with rather superlative descriptions of their power and capabilities.

The whole production is very much in the spirit of the times, though unexpectedly it makes no mention whatsoever of the Space Race with the Soviet Union, whose own rocket program had put the first satellite and the first man into space, and which was also secretly aiming for the moon. It’s somewhat jarring to understand that the people in this video had little idea that such an ambitious program would be as successful as it became, or even that in the wake of Kennedy’s assassination the following year there would be such an effort to fulfill the aim set out in his speech to reach the moon within the decade.

The moon landings, and the events and technology that made them possible, are a subject of considerable fascination for our community. We must have covered innumerable stories about artifacts from the Apollo era in these pages, and no doubt more will continue to come our way in the future. Films like this one do not tell us quite the same story as does a real artifact, but their values lies in capturing the optimism of the time. Anything seemed possible in 1962, and those who lived through the decade were lucky enough to see this proven.

Fifty years from now, what burgeoning engineering efforts will we look back on?

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Retrotechtacular: Operation Smash Hit

April 11, 2018 by Jenny List 12 Comments

Judging by the number of compilations that have been put online, one of the not-so-secret vices of the YouTube generation must be the watching of crash videos. Whether it is British drivers chancing their luck on level crossings, Russians losing it at speed on packed snow, or Americans driving tall trucks under low bridges, these films exert a compelling fascination upon the viewing public intent on deriving entertainment from the misfortunes of others. The footage is often peripheral or grainy, having inevitably been captured by a dashcam or a security camera rather than centre-stage on a broadcast quality system with professional operation. You can’t predict when such things will happen.

There was one moment, back in 1984, when predicting a major crash was exactly what you could do. It was a national event, all over the TV screens, and one which was watched by millions. The operators of British nuclear power stations wished to stage a public demonstration of how robust their transport flasks for spent nuclear fuel rods were, so after all the lab tests they could throw at one they placed it on a railway test track and crashed a 100mph express train into it.

This was as much a PR stunt as it was a scientific endeavour, and they lost no time in promoting it across all media. The film below the break was part of this effort, and takes us through the manufacture of the flask forged in one piece from huge billets of steel, before showing us the tests to which it was subjected. The toughest of these, a drop-test onto a corner of a fully laden flask, resulted in a small escape of the water contained within it. It was thus decided to conduct the ultimate test to ensure full public confidence in nuclear transport.

The Old Dalby test track is a section of a closed-to-passengers line in the English Midlands that was retained by British Railways as a proving ground for new locomotives. In the ultimate test of rail transport for nuclear waste, a flask was placed on its side across a piece of the track, and a train formed of a withdrawn 1960s locomotive and a short rake of 1950s carriages was accelerated without a driver over several miles to 100mph.

An instant before impact, we see the underside of the derailed car. The flask is between it and the locomotive.

[Nigel Harris] for Rail magazine wrote an almost funerial description of the destruction of locomotive 46009 25 years later in 2009, and as he reported the flask survived with only superficial damage and a tiny loss in pressure. The event was hailed as a success by the nuclear industry, before fading from the public consciousness as nuclear power station operators prefer to remain out of the news.

It is questionable how much the Old Dalby crash was for the cameras and the public, and how much it was for the scientists and engineers. But such destructive tests do serve as a means to gain vital test data that could not be harvested any other way, and have been performed more than once in the aviation industry. Later in the same year a Boeing 720 was crashed for science in the USA, while more recently in 2012 a Boeing 727 was crashed in Mexico.

Crashing an express train into a nuclear flask is something not likely to be seen again, it was a one-off event. But one thing’s for sure, our inability to turn away from watching a train wreck is nothing new. YouTube and ubiquitous cameras certainly make crashes available with a few keystrokes. But from the 1984 cask crash test, to the the spectacle of Crush, Texas back in 1896, the sheer power shown in these crashes seems to have a siren song effect on us.

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