A Mainframe Computer For The Modern Age

The era of mainframe computers and directly programming machines with switches is long past, but plenty of us look back on that era with a certain nostalgia. Getting that close to the hardware and knowing precisely what’s going on is becoming a little bit of a lost art. That’s why [Phil] took it upon himself to build this homage to the mainframe computer of the 70s, which all but disappeared when PCs and microcontrollers took over the scene decades ago.

The machine, known as PlasMa, is not a recreation of any specific computer but instead looks to recreate the feel of computers of this era in a more manageable size. [Phil] built the entire machine from scratch, and it can be programmed directly using toggle switches to input values into registers and memory. Programs can be run or single-stepped, and breakpoints can be set for debugging. The internal workings of the machine, including the program counter, instruction register, accumulator, and work registers, are visible in binary lights. Front panel switches let you control those same items.

The computer also hosts three different microcodes, each providing a unique instruction set. Two are based on computers from Princeton, Toy-A, and Toy-B, used as teaching tools. The third is a more advanced instruction set that allows using things like emulated peripherals, including storage devices. If you want to build one or just follow along as the machine is constructed, programmed, and used, [Phil] has a series of videos demonstrating its functionality, and he’s made everything open-source for those more curious. It’s a great way to get a grasp on the fundamentals of computing, and the only way we could think of to get even more into the inner workings of a machine like this is to build something like a relay computer.

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Recreating The Golden Era Of Cable TV

Fewer and fewer people have cable TV subscriptions these days, due to a combination of poor business practices by cable companies and the availability of alternatives to cable such as various streaming platforms. But before the rise of the Internet that enabled these alternatives, there was a short period of time where there were higher-quality channels, not too many commercials, a possibly rose-tinted sense of wonder, and where MTV actually played music. [Irish Craic Party] created this vintage cable TV network to capture this era of television history.

The hardware for this build is a Raspberry Pi driving an LCD display recovered from an old iPad. There’s a custom TV tuner which handles changing the channels and interfaces with an Apple Remote. Audio is sent through old computer speakers, and the case is built from 3D printed parts and some leftover walnut plywood to give it an era-appropriate 80s or early 90s feel. We’ve seen other builds like this before, but where this one really sets itself apart is in the software that handles the (television) programming.

[Irish Craic Party] has gone to great lengths here to recreate the feel of cable TV from decades ago. It has recreations of real channels like HBO, Nickelodeon, and FX including station-appropriate bumpers and commercials. It’s also synchronized to the clock so shows start on the half- or quarter-hour. Cartoons play on Saturday morning, and Nickelodeon switches to Nick-at-Nite in the evenings. There are even channels that switch to playing Christmas movies at the appropriate times, complete with Christmas-themed commercials.

The build even hosts a preview channel, one of the more challenging parts of the build. It continually scrolls through the channels and shows what’s currently playing and what will be showing shortly, complete with a commercial block at the top. For those who were around in the 90s it’s almost a perfect recreation of the experience of watching TV back then. It can even switch to a video game input when tuned to channel 3. There’s almost too much to go into in a short write-up so be sure to check the video after the break.

Thanks to [PCrozier] for the tip!

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Computer Speed Gains Erased By Modern Software

[Julio] has an older computer sitting on a desk, and recorded a quick video with it showing how fast this computer can do seemingly simple things, like open default Windows applications including the command prompt and Notepad. Compared to his modern laptop, which seems to struggle with even these basic tasks despite its impressive modern hardware, the antique machine seems like a speed demon. His videos set off a huge debate about why it seems that modern personal computers often appear slower than machines of the past.

After going through plenty of plausible scenarios for what is causing the slowdown, [Julio] seems to settle on a nuanced point regarding abstraction. Plenty of application developers are attempting to minimize the amount of development time for their programs while maximizing the number of platforms they run on, which often involves using a compatibility layer, which abstracts the software away from the hardware and increases the overhead needed to run programs. Things like this are possible thanks to the amount of computing power of modern machines, but not without a slight cost of higher latency. For applications developed natively, the response times would be expected to be quite good, but fewer applications are developed natively now including things that might seem like they otherwise would be.  Notepad, for example, is now based on UWP.

While there are plenty of plausible reasons for these slowdowns in apparent speed, it’s likely a combination of many things; death by a thousand cuts. Desktop applications built with a browser compatibility layer, software companies who are reducing their own costs by perhaps not abiding by best programming practices or simply taking advantage of modern computing power to reduce their costs, and of course the fact that modern software often needs more hardware resources to run safely and securely than equivalents from the past.

Retro-Inspired Computer Case Hosts Mechanical Keyboard

During the time in the 1980s when the personal computer was gaining steam as a household fixture, plenty of models shipped with the keyboard built in to the machine itself. This helped reduce costs, lower the physical footprint of the device, and arguably improved aesthetics. But as technology progressed, this type of design fell by the wayside as computers became more modular and configurable. That’s not to say there aren’t any benefits to building a computer like this, though. [jit] is here to show off this Amiga-inspired computer with its own modern built-in mechanical keyboard.

Like the Raspberry Pi 400 which is built into its own case, modern computers like this are extremely portable, relatively simple, and space-efficient. But [jit] did not like the uninspired design of the Pi so he was looking to make some improvements. Starting with the keyboard, it boasts a 60% size board with mechanical keys which are backlit by LEDs. Inside the machine is a Odroid XU4 which has a little bit more power (and is often easier to find) than a comparable Raspberry Pi. The case is 3D printed and includes ventilation and support for the addition of various cooling fans, I/O ports, status LEDs, and switches for the computer inside.

Additionally, some modification of the Odroid itself was needed in order to move the various switches to the case, and the build also includes a somewhat customized power supply internally as well. It’s a well-rounded build that captures the spirit of the old computer cases, but takes advantage of a lot of modern technology at the same time. If you want to go all-out with a build like this, though, take a look at this retro-inspired case (with keyboard included) that manages to get most of a Framework laptop inside.

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A Mobile Phone From 1985

It might seem quaint through the lends of history we have the luxury of looking through, but in the mid 1980s it was a major symbol of status to be able to communicate on-the-go. Car phones and pagers were cutting-edge devices of the time, and even though there were some mobile cellular telephones, they were behemoths compared to anything we would recognize as a cell phone today. It wasn’t until 1985 that a cell phone was able to fit in a pocket, and that first device wasn’t just revolutionary because of its size. It made a number of technological advancements that were extremely impressive for its time, and [Janus Cycle] takes us through some of those in this teardown video.

The Technophone came to us from Great Britain by way of a former Ericsson engineer named Nils Mårtensson. It was able to achieve its relatively small stature using a surface-mount PCB, which was a cutting-edge manufacturing process for the time. Not only did it use surface-mount components and boards, but the PCB itself has 12 layers and two sides and hosts two custom Technophone chips. The phone is relatively modular as well, with the screen, battery pack, and other components capable of easily disconnecting from the main board. Continue reading “A Mobile Phone From 1985”

Exploring The Early Days Of QRP Radio

Morse code might seem obsolete but for situations with extremely limited bandwidth it’s often still the best communications option available. The code requires a fair amount of training to use effectively, though, and even proficient radio operators tend to send only around 20 words per minute. As a result of the reduced throughput, a type of language evolved around Morse code which, like any language, has evolved and changed over time. QRP initially meant something akin to “you are overloading my receiver, please reduce transmitter power” but now means “operating radios at extremely low power levels”. [MIKROWAVE1] explores some of the earlier options for QRP radios in this video.

There’s been some debate in the amateur radio community over the years over what power level constitutes a QRP operation, but it’s almost certainly somewhere below 100 watts, and while the radios in this video have varying power levels, they tend to be far below this upper threshold, with some operating on 1 watt or less. There are a few commercial offerings demonstrated here, produced from the 70s to the mid-80s, but a few are made from kits as well. Kits tended to be both accessible and easily repairable, with Heathkit being the more recognizable option among this category. To operate Morse code (or “continuous wave” as hams would call it) only requires a single transistor which is why kits were so popular, but there are a few other examples in this video with quite a few more transistors than that. In fact, there are all kinds of radios featured here with plenty of features we might even consider modern by today’s standards; at least when Morse code is concerned.

QRP radios in general are attractive because they tend to be smaller, simpler, and more affordable. Making QRP contacts over great distances also increases one’s ham radio street cred, especially when using Morse, although this benefit is more intangible. There’s a large trend going on in the radio world right now surrounding operating from parks and mountain peaks, which means QRP is often the only way to get that done especially when operating on battery power. Modern QRP radios often support digital and voice modes as well and can have surprisingly high prices, but taking some cues from this video about radios built in decades past could get you on the radio for a minimum or parts and cost, provided you can put in the time.

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SheepShaver: A Cross-Platform Tool For Retro Enthusiasts

The world of desktop computing has coalesced into what is essentially a duopoly, with Windows machines making up the bulk of the market share and Apple carving out a dedicated minority. This relatively stable state hasn’t always existed, though, as the computing scene even as late as the 90s was awash with all kinds of competing operating systems and various incompatible hardware. Amiga, Unix, OS/2, MacOS, NeXT, BeOS, as well as competing DOSes, were all on the table at various points.

If you’ve still got a box running one of these retro systems, SheepShaver might be able to help expand your software library. It’s not the sort of virtualization that we’re used to in the modern world, with an entire operating system running on a sanctioned-off part of your system. But SheepShaver does allow you to run software written for MacOS 7.5.2 thru 9.0.4 in a different environment. Unix and Linux are both supported, as well as Mac OS X, Windows NT, 2000, and XP, and the enigmatic BeOS. Certain configurations allow applications to run natively without any emulation at all, and there is plenty of hardware support built-in as well.

For anyone running retro hardware from the late 90s or early 00s, this could be just the ticket to get an application running that wasn’t ever supported on one of these machines. As for the name, it’s a play on another piece of software called ShapeShifter which brought a Mac-II emulator to the Amiga. SheepShaver has been around since the late 90s, too, so we’re surprised that we haven’t featured it before since it is such a powerful tool for cross-platform compatibility for computers of this era. Even if all you are hanging on to is an old BeBox.