The History Of Tandem Computers

January 26, 2026 by Al Williams 5 Comments

If you are interested in historical big computers, you probably think of IBM, with maybe a little thought of Sperry Rand or, if you go smaller, HP, DEC, and companies like Data General. But you may not have heard of Tandem Computers unless you have dealt with systems where downtime was unacceptable. Printing bills or payroll checks can afford some downtime while you reboot or replace a bad board. But if your computer services ATM machines, cash registers, or a factory, that’s another type of operation altogether. That was where Tandem computers made their mark, and [Asianometry] recounts their history in a recent video that you can watch below.

When IBM was king, your best bet for having a computer running nonstop was to have more than one computer. But that’s pricey. Computers might have some redundancy, but it is difficult to avoid single points of failure. For example, if you have two computers with a single network connection and a single disk drive. Then failures in the network connection or the disk drive will take the system down.

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One Hundred Years Of Telly

January 26, 2026 by Jenny List 10 Comments

Today marks an auspicious anniversary which might have passed us by had it not been for [Diamond Geezer], who reminds us that it’s a hundred years since the first public demonstration of television by John Logie Baird. In a room above what is today a rather famous Italian coffee shop in London’s Soho, he had assembled a complete mechanical TV system that he demonstrated to journalists.

Television is one of those inventions that owes its genesis to more than a single person, so while Baird was by no means the only one inventing in the field, he was the first to demonstrate a working system. With mechanical scanning and just 30 lines, it’s hardly HD or 4K, but it does have the advantage of being within the reach of the constructor.

Perhaps the saddest thing about Baird and his system is that while he was able to attract the interest of the BBC in it, when the time came for dedicated transmissions at a higher resolution, his by then partly mechanical system could not compete and he faded into relative obscurity. Brits instead received EMI’s 405 line system, which persisted until the very start of the 1980s, and eventually the German PAL colour system in the late 1960s.

So head on down to Bar Italia if you can to raise a coffee to his memory, and should you wish to have a go at Baird-style TV for yourself, then you may need to print yourself a disk.

Header image: Matt Brown, CC BY 2.0.

Create A Tiny Telephone Exchange With An Analog Telephone Adapter

January 26, 2026 by Maya Posch 13 Comments

An analog telephone adapter (ATA), or FXS gateway, is a device that allows traditional analog phones to be connected to a digital voice-over-IP (VoIP) network. In addition to this, you can even create a local phone exchange using just analog phones without connecting to a network as [Playful Technology] demonstrates in a recent video.

The ATA used in the video is the Grandstream HT802, which features one 10/100 Mbps Ethernet port and two RJ11 FXS ports for two POTS phones, allowing for two phones to be directly connected and configured using their own profiles.

By using a multi-FXS port ATA in this manner, you essentially can set up your own mini telephone exchange, with a long run of Cat-3 possible between an individual phone and the ATA. Use of the Ethernet port is necessary just once to configure the ATA, as demonstrated in the video. The IP address of the ATA is amusingly obtained by dialing *** on a connected phone and picking 02 as menu option after which a synthetic voice reads out the number. This IP address gets you into the administration interface.

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Restoring A 1924 Frigidaire B-9 Refrigerator Back To Working Condition

January 26, 2026 by Maya Posch 13 Comments

Before the refrigerator became a normal part of any kitchen, those with enough money to throw around could get an icebox, which used melting ice to cool food and drinks in a second compartment. As refrigerators became available for sale in the 1920s, this created somewhat awkward transition models, like the 1924 Frigidaire B-9 that [David Allen] recently got offered for a restoration. This was part of the restoration of a 1926 house, which foresaw putting this venerable unit back into operation.

As [David] explains, this refrigerator was still in use until about 1970 when it broke down, and repairs proved tricky. Clearly, the fault wasn’t that severe as [David] got it working again after a number of small repairs and a lot of maintenance. The running unit with its basic elements can be seen purring away in the completion video, with the journey to get there covered in a video series starting with the first episode.

What’s fascinating is that during this aforementioned transition period, the vapor compression electric cooling system was an optional extra, meaning that the basic layout is still that of an icebox. Correspondingly, instead of ice in the ice compartment, you find the low-side float evaporator, with the basement section containing the condensing unit, motor, and compressor. The temperature sensor is also a miracle of simplicity, using bellows that respond to the temperature and thus volume of the evaporator coolant, which trigger a switch that turns on the compressor.

Despite a hundred years having passed since this refrigerator was constructed, at its core it works exactly the same as the unit we have in our kitchens today, albeit with higher efficiency, more electronics, and with the sulfur dioxide refrigerant replaced with something less toxic to us humans.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Split With The Num Pad

January 26, 2026 by Kristina Panos 5 Comments

I love, love, love Saturn by [Rain2], which comes in two versions. The first, which is notably more complex, is shown here with its rings-of-Saturn thumb clusters.

A brightly-colored split with a built-in num pad on the right half. — Image by [Rain2] via reddit

So what was the impetus for this keyboard? It’s simple: a friend mentioned that ergo keyboards are a no-go if you need a num pad really bad.

Saturn has one built right in. The basic idea was to add a num pad while keeping the total number of keys to a minimum. Thanks to a mod key, this area can be many things, including but not limited to a num pad.

As far as the far-out shape goes, and I love that the curvature covers the thumb cluster and the index finger, [Rain2] wanted to get away from the traditional thumb cluster design. Be sure to check out the back of the boards in the image gallery.

Unfortunately, this version is too complicated to make, so v2 does not have the cool collision shapes going for it. But it is still an excellent keyboard, and perhaps will be open source someday.

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Astronomy Live On Twitch

January 26, 2026 by Bryan Cockfield 11 Comments

Although there are a few hobbies that have low-cost entry points, amateur astronomy is not generally among them. A tabletop Dobsonian might cost a few hundred dollars, and that is just the entry point for an ever-increasing set of telescopes, mounts, trackers, lasers, and other pieces of equipment that it’s possible to build or buy. [Thomas] is deep into astronomy now, has a high-quality, remotely controllable telescope, and wanted to make it more accessible to his friends and others, so he built a system that lets the telescope stream on Twitch and lets his Twitch viewers control what it’s looking at.

The project began with overcoming the $4000 telescope’s practical limitations, most notably an annoyingly short Wi-Fi range and closed software. [Thomas] built a wireless bridge with a Raspberry Pi to extend connectivity, and then built a headless streaming system using OBS Studio inside a Proxmox container. This was a major hurdle as OBS doesn’t have particularly good support for headless operation.

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Does Carbon Fiber PLA Make Sense?

January 26, 2026 by Maya Posch 25 Comments

Carbon fiber (CF) has attained somewhat of a near-mystical appeal in consumer marketing, with it being praised for being stronger than steel while simultaneously being extremely lightweight. This mostly refers to weaved fibers combined with resin into a composite material that is used for everything from car bodies to bike frames. This CF look is so sexy that the typical carbon-fiber composite weave pattern and coloring have been added to products as a purely cosmetic accent.

More recently, chopped carbon fiber (CCF) has been added to the thermoplastics we extrude from our 3D printers. Despite lacking clear evidence of this providing material improvements, the same kind of mysticism persists here as well. Even as evidence emerges of poor integration of these chopped fibers into the thermoplastic matrix, the marketing claims continue unabated.

As with most things, there’s a right way and a wrong way to do it. A recent paper by Sameh Dabees et al. in Composites for example covered the CF surface modifications required for thermoplastic integration with CF.

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