computer hacks

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computer hacks

Scott holding the demo board which has a 7-segment display and keyboard attached

4-bit Single Board Computer Based On The Intel 4004 Microprocessor

September 11, 2025 by 8 Comments

[Scott Baker] is at it again and this time he has built a 4-bit single board computer based on the Intel 4004 microprocessor.

In the board design [Scott] covers the CPU (both the Intel 4004 and 4040 are supported), and its support chips: the 4201A clock-generator, its crystal, and the 4289 Standard Memory Interface. The 4289 irons out the 4-bit interface for use with 8-bit ROMs. Included is a ATF22V10 PLD for miscellaneous logic, a 74HCT138 for chip-select, and a bunch of inverters for TTL compatibility (the 4004 itself uses 15 V logic with +5 V Vss and -10 V Vdd).

[Scott] goes on to discuss the power supply, ROM and page mapper, the serial interface, the RC2014 bus interface, RAM, and the multimodule interface. Then comes the implementation, a very tidy custom PCB populated with a bunch of integrated circuits, some passive components, a handful of LEDs, and a few I/O ports. [Scott] credits Jim Loo’s Intel 4004 SBC project as the genesis of his own build.

If you’re interested in seeing this board put to work check out the video embedded below. If you’d like to know more about the 4004 be sure to check out Supersize Your Intel 4004 By Over 10 Times, The 4004 Upgrade You’ve Been Waiting For, and Calculating Pi On The 4004 CPU, Intel’s First Microprocessor.

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A photo of two magnetic bubble memories installed in a circuit board

Scott Baker’s Magnetic Bubble Memory Mega-Post

September 5, 2025 by 11 Comments

Over on his blog our hacker [Scott Baker] has a Magnetic Bubble Memory Mega-Post.

If you haven’t heard of magnetic bubble memory before it’s basically obsolete nonvolatile memory. Since the 1970s when it was introduced this type of memory has been outperformed in every dimension including durability, reliability, price, density, performance, and so on. For any given application of bubble memory you will be able to find an alternative technology which is better in many ways. Except if you want some old tech to geek out over, in that case magnetic bubble memory is for you!

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CPU Utilization Not As Easy As It Sounds

September 4, 2025 by 12 Comments

If you ever develop an embedded system in a corporate environment, someone will probably tell you that you can only use 80% of the CPU or some other made-up number. The theory is that you will need some overhead for expansion. While that might have been a reasonable thing to do when CPUs and operating systems were very simple, those days are long gone. [Brendan Long] explains at least one problem with the idea in some recent tests he did related to server utilization.

[Brendan] recognizes that a modern CPU doesn’t actually scale like you would think. When lightly loaded, a modern CPU might run faster because it can keep other CPUs in the package slower and cooler. Increase the load, and more CPUs may get involved, but they will probably run slower. Beyond that, a newfangled processor often has fewer full CPUs than you expect. The test machine was a 24-core AMD processor. However, there are really 12 complete CPUs that can fast switch between two contexts. You have 24 threads that you can use, but only 12 at a time. So that skews the results, too.

Of course, our favorite problem is even more subtle. A modern OS will use whatever resources would otherwise go to waste. Even at 100% load, your program may work, but very slowly. So assume the boss wants you to do something every five seconds. You run the program. Suppose it is using 80% of the CPU and 90% of the memory. The program can execute its task every 4.6 seconds. So what? It may be that the OS is giving you that much because it would otherwise be idle. If you had 50% of the CPU and 70% of the memory, you might still be able to work in 4.7 seconds.

A better method is to have a low-priority task consume the resources you are not allowed to use, run the program, and verify that it still meets the required time. That solves a lot of [Brendan’s] observations, too. What you can’t do is scale the measurement linearly for all these reasons and probably others.

Not every project needs to worry about performance. But if you do, measuring and predicting it isn’t as straightforward as you might think. If you are interested in displaying your current stats, may we suggest analog? You have choices.

Scott and his Prompt 80

Restoring A Vintage Intel Prompt 80 8080 Microcomputer Trainer

September 3, 2025 by 3 Comments

Over on his blog our hacker [Scott Baker] restores a Prompt 80, which was a development system for the 8-bit Intel 8080 CPU.

[Scott] acquired this broken trainer on eBay and then set about restoring it. The trainer provides I/O for programming, probing, and debugging an attached CPU. The first problem discovered when opening the case is that the CPU board is missing. The original board was an 80/10 but [Scott] ended up installing a newer 80/10A board he scored for fifty bucks. Later he upgraded to an 80/10B which increased the RAM and added a multimodule slot.

[Scott] has some luck fixing the failed power supply by recapping some of the smaller electrolytic capacitors which were showing high ESR. Once he had the board installed and the power supply functional he was able to input his first assembly program: a Cylon LED program! Making artistic use of the LEDs attached to the parallel port. You can see the results in the video embedded below.

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Remembering The Intel Compute Stick

September 2, 2025 by 29 Comments

Over the years Intel has introduced a number of new computer form factors that either became a hit, fizzled out, or moved on to live a more quiet life. The New Unit of Computing (NUC) decidedly became a hit with so-called Mini PCs now everywhere, while the Intel Compute Stick has been largely forgotten. In a recent video by the [Action Retro] one such Compute Stick is poked at, specifically the last model released by Intel in the form of the 2016-era STK1AW32SC, featuring a quad-core Intel Atom x5-Z8330 SoC, 2 GB of RAM and 32 GB eMMC storage.

As the name suggests, this form factor is very stick-like, with a design that makes it easy to just plug it into the HDMI port of a display, making it a snap to add a computer to any TV or such without taking up a considerable amount of space. Although Intel didn’t make more of them after this model, it could be argued that devices like the Chromecast dongle follow the same general concept, and manufacturers like MeLe are still making new PCs in this form factor today.

In the video this 2016-era Compute Stick is put through its paces, wiping the Windows 10 installation that was still on it from the last time it was used, and an installation of Haiku was attempted which unfortunately failed to see the eMMC storage. Worse was the current Ubuntu, which saw its installer simply freeze up, but MX Linux saved the day, providing a very usable Linux desktop experience including the watching of YouTube content and network streaming of Steam games.

Although dissed as ‘e-waste’ by many today, if anything this video shows that these little sticks are still very capable computers in 2025.

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NFC Hidden In Floppy Disk For Retro-Themed PC

August 29, 2025 by 13 Comments

As we all look across a sea of lifeless, nearly identically-styled consumer goods, a few of us have become nostalgic for a time when products like stereo equipment, phones, appliances, homes, cars, and furniture didn’t all look indistinguishable. Computers suffered a similar fate, with nearly everything designed to be flat and minimalist with very little character. To be sure there are plenty of retro computing projects to recapture nostalgia, but to get useful modern hardware in a fun retro-themed case check out this desktop build from [Mar] that hides a few unique extras.

The PC itself is a modern build with an up-to-date operating system, but hidden in a 386-era case with early-90s styling. The real gem of this build though is the floppy disk drive, which looks unaltered on the surface. But its core functionality has been removed and in its place an Arduino sits, looking for NFC devices. The floppy disks similarly had NFC tags installed so that when they interact with the Arduino, it can send a command to the computer to launch a corresponding game. To the user it looks as though the game loads from a floppy disk, much like it would have in the 90s albeit with much more speed and much less noise.

Modern industrial design is something that we’ve generally bemoaned as of late, and it’s great to see some of us rebelling by building unique machines like this, not to mention repurposing hardware like floppy drives for fun new uses (which [Mar] has also open-sourced on a GitHub page). It’s not the first build to toss modern hardware in a cool PC case from days of yore, either. This Hot Wheels desktop is one of our favorites.

Steampunk Copper PC Is As Cool As It Runs

August 14, 2025 by 26 Comments

Copper! The only thing it does better than conduct heat is conduct a great steampunk vibe. [Billet Labs]’ latest video is an artfully done wall PC that makes full use of both of those properties.

The parts are what you’d expect in a high-end workstation PC: a Ryzen 9 and an 3090Ti with oodles of RAM. It’s the cooling loop where all the magic happens: from the copper block on the CPU, to the plumbing fixtures that give the whole thing a beautiful brewery-chiq shine when polished up. Hopefully the water-block in the GPU is equally cupriferous too, but given the attention to detail in the rest of the build, we cannot imagine [Billet Labs] making such a rookie mistake as to invite Mr. Galvanic Corrosion to the party.

There’s almost no visible plastic or paint; the GPU and PSU are hidden by a brass plates, and even the back panel everything mounts to is shiny metal. Even the fans on the radiator are metal, and customized to look like a quad throttle body or four-barreled carburetor on an old race car. (Though they sound more like a jet takeoff.)

The analog gauges are a particular treat, which push this build firmly into “steampunk” territory. Unfortunately the temperature gauge glued onto the GPU only measures the external temperature of the GPU, not the temperature at the die or even the water-block. On the other hand, given how well this cooling setup seems to work later in the video, GPU temps are likely to stay pretty stable. The other gauges do exactly what you’d expect, measuring the pressure and temperature of the water in the coolant loop and voltage on the twelve volt rail.

Honestly, once it gets mounted on the wall, this build looks more like an art piece than any kind of computer— only the power and I/O cables do anything to give the game away. Now that he has the case, perhaps some artful peripherals are in order?

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