Retrotechtacular: The IBM 7070

March 29, 2024 by Al Williams 10 Comments

If you think of IBM mainframe computers, you most likely are thinking of the iconic S/360 or the slightly newer S/370. But what about the 7070 from 1958? It had transistors! It didn’t, however, use binary. Instead, it was a decimal-architecture machine. You can see a lost video of the machine below.

It was originally slated to upgrade the older IBM 650 and 705 computers. However, it wasn’t compatible with either, so IBM had to roll out the IBM7080, which was compatible, at least, with the 705. Both machines could run 650 code via emulation.

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Retrotechtacular: TOPS Runs The 1970s British Railroad

March 27, 2024 by Al Williams 29 Comments

How do you make the trains run on time? British Rail adopted TOPS, a computer system born of IBM’s SAGE defense project, along with work from Standford and Southern Pacific Railroad. Before TOPS, running the railroad took paper. Lots of paper, ranging from a train’s history, assignments, and all the other bits of data required to keep the trains moving. TOPS kept this data in real-time on computer screens all across the system. While British Rail wasn’t the only company to deploy TOPS, they were certainly proud of it and produced the video you can see below about how the system worked.

There are a lot of pictures of old big iron and the narrator says it has an “immense storage capacity.” The actual computers in question were a pair of IBM System/370 mainframes that each had 4 MB of RAM. There were also banks of 3330 disk drives that used removable disk packs of — gasp — between 100 and 200 MB per pack.

As primitive and large as those disk drives were, they pioneered many familiar-sounding technologies. For example, they used voice coils, servo tracking, MFM encoding, and error-correcting encoding.

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Retrotechtacular: Build Your Own Dune Buggy, 1970s Style

March 26, 2024 by Jenny List 21 Comments

The custom car phenomenon is as old as the second-hand car, yet somehow the decades which stick in the mind as their heyday are the 1960s and 1970s. If you didn’t have a dune buggy or a van with outrageously flared arches and an eye-hurting paint job you were nothing in those days — or at least that’s what those of us who were too young to possess such vehicles except as posters on our bedroom walls were led to believe. Periscope Films have put up a period guide from the early 1970s on how to build your own dune buggy, and can we just say it’s got us yearning to drive something just as outrageous?

Of course, auto salvage yards aren’t bursting with Beetles as donor cars in 2024, indeed the accident-damaged model used in the film would almost certainly now be lovingly restored instead of being torn apart to make a dune buggy. We’re taken through the process of stripping and shortening the Beetle floorpan, for which we’re thankful that in 2024 we have decent quality cutting disks, and watching the welder joining thin sheet metal with a stick welder gives us some serious respect for his skills.

Perhaps the part of this video most likely to raise a smile is how it portrays building a car as easy. Anyone who has ever hacked a car to pieces will tell you that’s the easy part, and it’s the building something from the pile of rusty parts which causes so many projects to fail. But given an accident damaged Beetle and a buggy kit in 1972 would we have dug in and given it a try? Of course!

We’ve touched on the Beetle’s hackability in the past, but some of us believe that the crown of most hackable car rests elsewhere.

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Retrotechtacular: Right To Repair 1987

March 24, 2024 by Al Williams 26 Comments

In 1987, your portable Osborne computer had a problem. Who you gonna call? Well, maybe the company that made “The Osborne Survival Kit,” a video from Witt Services acquired by the Computer History Museum. The narrator, [Mark Witt], tells us that they’ve been fixing these computers for more than three years, and they want to help you fix it yourself. Those days seem long gone, don’t they?

Of course, one thing you need to know is how to clean your floppy drives. The procedure is easy; even a 10-year-old can do it. At least, we think [William Witt] is about 10 in the video. He did a fine job, and we wonder what he’s up to these days.

The next step was taking the machine apart, but that required adult supervision. In some cases, it also took a soldering iron. As a byproduct, the video inadvertently is a nice tear-down video, too.

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Retrotechtacular: Air Mail For The Birds

March 14, 2024 by Al Williams 9 Comments

Today, if you want to send a message to a distant location, you’ll probably send an e-mail or a text message. But it hasn’t always been that easy. Military commanders, in particular, have always needed ways to send messages and were early adopters of radio and, prior to that, schemes like semaphores, drums, horns, Aldis lamps, and even barrels of water to communicate over distances.

One of the most reliable ways to pass messages, even during the last world war, was by carrier pigeon. Since the U.S. Army Signal Corps handled anything that included messages, it makes sense that the War Department issued TM 11-410 about how to use and care for pigeons. Think of it as the network operations guide of 1945. The practice, though, is much older. There is evidence that the Persians used pigeons in the 6th century BC, and Julius Caesar’s army also used the system.

You wouldn’t imagine that drawing an assignment in the Signal Corps might involve learning about breeding pigeons, training them, and providing them with medical attention, but that’s what some Signal Corps personnel did. The Army started experimenting with pigeons in 1878, but the Navy was the main user of the birds until World War I, when the U.S. Pigeon Intelligence Service was formed. In World War II, they saw use in situations where radio silence was important, like the D-Day invasion.

The Navy also disbanded its earlier Pigeon Messenger Service. It then returned to avian communications during the World Wars, using them to allow aviators to send messages back to base without radio traffic. The Navy had its own version of the pigeon manual.

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Retrotechtacular: The Free Piston Engine

March 4, 2024 by Jenny List 20 Comments

We all know how a conventional internal combustion engine works, with a piston and a crankshaft. But that’s by no means the only way to make an engine, and one of the slightly more unusual alternatives comes to us courtesy of a vintage Shell Film Unit film, The Free Piston Engine, which we’ve placed below the break. It’s a beautiful period piece of mid-century animation and jazz, but it’s also an introduction to these fascinating machines.

We’re introduced to the traditional two-stroke diesel engine as thermally efficient but not smooth-running, and then the gas turbine as smooth but much more inefficient. The free piston engine, a design with opposed pistons working against compressed air springs and combining both compression and firing strokes in a single axis, doesn’t turn anything in itself, but instead works as a continuous supplier of high pressure combustion gasses. The clever part of this arrangement is that these gasses can then turn the power turbine from a gas turbine engine, achieving a smooth engine without compromising efficiency.

This sounds like a promising design for an engine, and we’re introduced to a rosy picture of railway locomotives, ships, factories, and power stations all driven by free piston engines. Why then, here in 2024 do we not see them everywhere? A quick Google search reveals an inordinately high number of scientific review papers about them but not so many real-world examples. In that they’re not alone, for alternative engine designs are one of those technologies for which if we had a dollar for every one we’d seen that didn’t make it, as the saying goes, we’d be rich.

It seems that the problem with these engines is that they don’t offer the control over their timing that we’re used to from more conventional designs, and thus the speed of their operation also can’t be controlled. The British firm Libertine claim to have solved this with their line of linear electrical generators, but perhaps understandably for commercial reasons they are a little coy about the details. Their focus is on free piston engines as power sources for hybrid electric vehicles, something which due to their small size they seem ideally suited for.

Perhaps the free piston engine has faced its biggest problem not in the matter of technology but in inertia. There’s an old saying in the computer industry: “Nobody ever got fired for buying IBM“, meaning that the conventional conservative choice always wins, and it’s fair to guess that the same applies anywhere a large engine has been needed. A conventional diesel engine may be a complex device with many moving parts, but it’s a well-understood machine that whoever wields the cheque book feels comfortable with. That’s a huge obstacle for any new technology to climb. Meanwhile though it offers obvious benefits in terms of efficiency, at the moment its time could have come due to environmental concerns, any internal combustion engine has fallen out of fashion. It’s possible that it could find a life as an engine running on an alternative fuel such as hydrogen or ammonia, but we’re not so sure. If new free piston engines do take off though, we’ll be more pleased than anyone to eat our words.

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A man standing next to a log holds a wooden mallet and a grey froe with a wooden handle. The froe's long straight blade sits atop the end of the log. Several cuts radiate out from the center of the log going through the length of the wood.

Making Wooden Shingles With Hand Tools

February 22, 2024 by Navarre Bartz 23 Comments

While they have mostly been replaced with other roofing technologies, wooden shingles have a certain rustic charm. If you’re curious about how to make them by hand, [Harry Rogers] takes us through his friend [John] making some.

There are two primary means of splitting a log for making shingles (or shakes). The first is radial, like one would cut a pie, and the other is lateral, with all the cuts in the same orientation. Using a froe, the log is split in progressively smaller halves to control the way the grain splits down the length of the log and minimize waste. Larger logs result in less waste and lend themselves to the radial method, while smaller logs must be cut laterally. Laterally cut shingles have a higher propensity for warping and other issues, but will work when larger logs are not available.

Once the pieces are split out of the log, they are trimmed with an axe, including removing the outer sapwood which is the main attractant for bugs and other creatures that might try eating your roof. Once down to approximately the right dimensions, the shingle is then smoothed out on a shave horse with a draw knife. Interestingly, the hand-made shingles have a longer lifespan than those sawn since the process works more with the grain of the wood and introduces fewer opportunities for water to seep into the shingles.

If you’re looking for something more solarpunk and less cottagecore for your house, maybe try a green solar roof, and if you’ve got a glass roof, try cleaning it with the Grawler.

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