Retrocomputing

1571 Articles

M8SBC-486 Is An FPGA-Based “Kinda PC Compatible” 486 SBC

January 8, 2026 by 25 Comments

[Editor’s note: We got this one wrong! The computer uses an actual 486: the FPGA is running essentially as the chipset, interfacing the RAM and the ISA bus with the CPU. And since this went to press, [maniek-86] put out a nicer writeup of the project, which you should go check out, in addition to the GitHub link below.]

 

Given the technical specs of the FPGAs available to hobbyists these days, it really shouldn’t be a shock that you can implement a relatively-modern chipset on one, like one for a 486 system. In spite of knowing that in the technical sense, we were still caught off guard by [maniek-86]’s M8SBC project that does just that– the proas both CPU and BIOSducing a 486 FPGA chipset with a motherboard to boot.

Boot what? Linux 2.2.6, MS-DOS 6.22 or FreeDOS all work. It can run DOOM, of course, along with Wolfenstien 3D, Prince of Persia, and even the famous Second Reality demo– though that last without sound. [maniek-86]’s implementation is lacking direct memory access, so sound card support is right out. There are a few other bugs that are slowly being squished, too, according to the latest Reddit thread. Continue reading “M8SBC-486 Is An FPGA-Based “Kinda PC Compatible” 486 SBC” →

Ken Shirriff working on the Commodore PET

This 8-Bit Commodore PET Was Hard To Fix

January 6, 2026 by 13 Comments

Over on [Ken Shirriff]’s blog is a tricky Commodore PET repair: tracking down 6 1/2 bad chips. WARNING: contains 8-bit assembly code.

The Trinity of 1977 which started the personal computer revolution were the Apple II, the Commodore PET, and the TRS-80. In this project it’s a failing Commodore PET which is being restored.

Continue reading “This 8-Bit Commodore PET Was Hard To Fix” →

A photo of the PiStorm68K circuit board

PiStorm68K Offers Supercharged Retro Amiga Experience

January 6, 2026 by 11 Comments

[AmiCube] has announced their new PiStorm68K special edition MiniMig accelerator board. This board was developed to replace the 68000 CPU in a MiniMig — a recreation of the original Amiga chipset in an FPGA allowing a real genuine 68000 CPU to operate.

The PiStorm68K itself can host a real genuine 68000 CPU but it can also host various Raspberry Pi models which can do emulation of a 68000. So if you combine a PiStorm68K with a MiniMig you can, at your option, boot into an emulated environment with massively increased performance, or you can boot into an original environment, with its reliable and charming sluggishness.

In the introduction video below, [AmiCube] uses the SYSINFO utility software to compare the CPU speed when using emulation (1531 MIPS) versus the original (4.47 MIPS), where MIPS means Millions of Instructions Per Second. As you can see the 68000 emulated by the Raspberry Pi is way faster than the original. The Raspberry Pi also emulates a floating-point unit (FPU) which the original doesn’t include and a memory management unit (MMU) which isn’t used.

If you’re interested in old Amiga tech you might also like to read about Chip Swap Fixes A Dead Amiga 600 or The Many-Sprites Interpretation Of Amiga Mechanics.

Continue reading “PiStorm68K Offers Supercharged Retro Amiga Experience” →

Commodore Disk Drive Becomes General Purpose Computer

January 5, 2026 by 35 Comments

The Commodore 1541 was built to do one job—to save and load data from 5.25″ diskettes. [Commodore History] decided to see whether the drive could be put to other purposes, though. Namely, operating as a standalone computer in its own right!

It might sound silly, but there’s a very obvious inspiration behind this hack. It’s all because the Commodore 1541 disk drive contains a MOS 6502 CPU, along with some RAM, ROM, and other necessary supporting hardware. As you might remember, that’s the very same CPU that powers the Commodore 64 itself, along with a wide range of other 1980s machines. With a bit of work, that CPU can indeed be made to act like a general purpose computer instead of a single-purpose disk controller.

[Commodore History] compares the 1541 to the Commodore VIC-20, noting that the disk drive has a very similar configuration, but less than half the RAM. The video then explains how the drive can be reconfigured to run like the even-simpler MOS Technology KIM-1 — a very primitive but well-known 8-bit machine. What’s wild is that this can be achieved with no hardware modifications. It’s not just a thought exercise, either. We get a full “Hello World!” example running in both BASIC and machine code to demonstrate that it really works.

Code is on GitHub for the curious. We’ve featured hacks with the chunky Commodore 1541 before, too.

Continue reading “Commodore Disk Drive Becomes General Purpose Computer” →

Print Pixel Art To A Floppy Disk

January 4, 2026 by 3 Comments

Here at Hackaday we love floppy disks. While they are by no means a practical or useful means of storing data in the age of solid state storage, there is something special about the little floppy disc of magnetic film inside that iconic plastic case. That’s why we were so excited to see the tool [dbalsom] developed for printing pixel art in a floppy’s track timing diagrams!

Floppy timing diagrams are usually used to analyze the quality of an individual disk. It represents flux transitions within a single floppy tack as a 2D graph. But it’s also perfectly possible to “paint” images on a floppy this way. Granted, you can’t see these images without printing out a timing diagram, but if you’re painting images onto a floppy, that’s probably the point.

This is where pbm2track comes in handy! It takes bitmap images and encodes them onto floppy emulators, or actual floppies. The results are quite excellent, with near-perfect recreation in floppy graphical views. The results on real floppies are also recognizable as the original image. The concept is similar to a previous tool [dbalsom] created, PNG2disk

If you, too, love the nearly forgotten physical likeness of the save button, make sure to check out this modern Linux on a floppy hack next!

Thanks [gloriouscow] for the tip!

FPGA Dev Kit Unofficially Brings MSX Standard Back

January 3, 2026 by 15 Comments

In the 1980s there were an incredible number of personal computers of all shapes, sizes, and operating system types, and there was very little interoperability. Unlike today’s Windows-Mac duopoly, this era was much more of a free-for-all but that didn’t mean companies like Microsoft weren’t trying to clean up all of this mess. In 1983 they introduced the MSX standard for computers, hoping to coalesce users around a single design. Eventually it became very successful in Japan and saw some use in a few other places but is now relegated to the dustbin of history, but a new FPGA kit unofficially supports this standard.

The kit is called the OneChip Book and, unlike most FPGA kits, includes essentially everything needed to get it up and running including screen, keyboard, and I/O all in a pre-built laptop case. At its core it’s just that: and FPGA kit. But its original intent was to recreate this old 80s computer standard with modern hardware. The only problem is they never asked for permission, and their plans were quickly quashed. The development kit is still available, though, and [electricadventures] goes through the steps to get this computer set up to emulate this unofficially-supported retro spec. He’s also able to get original MSX cartridges running on it when everything is said and done.

Although MSX is relatively unknown in North America and Western Europe, it remains a fairly popular platform for retro computing enthusiasts in much of the rest of the world. We’ve seen a few similar projects related to this computer standard like this MSX-inspired cyberdeck design, but also others that bring new hardware to this old platform.

Continue reading “FPGA Dev Kit Unofficially Brings MSX Standard Back” →

Zork Running On 4-Bit Intel Computer

January 3, 2026 by 9 Comments

Before DOOM would run on any computing system ever produced, and indeed before it even ran on its first computer, the game that would run on any computer of the pre-DOOM era was Zork. This was a text-based adventure game first published in the late 70s that could run on a number of platforms thanks to a virtual machine that interpreted the game code. This let the programmers write a new VM for each platform rather than porting the game every time. [smbakeryt] wanted to see how far he could push this design and got the classic game running on one of the oldest computers ever produced.

The computer in question is the ubiquitous Intel 4004 processor, the first commercially available general-purpose microprocessor produced. This was a four-bit machine and predates the release of Zork by about eight years. As discussed earlier, though, the only thing needed to get Zork to run on any machine is the Z-machine for that platform, so [smbakeryt] got to work. He’s working on a Heathkit H9 terminal, and the main limitation here is the amount of RAM needed to run the game. He was able to extended the address bus to increase the available memory in hardware, but getting the Z-machine running in software took some effort as well. There’s a number of layers of software abstraction here that’s a bit surprising for 70s-era computing but which make it an extremely interesting challenge and project.

As far as [smbakeryt]’s goal of finding the “least amount of computer” that would play Zork, we’d have a hard time thinking of anything predating the 4004 that would have any reasonable user experience, but we’d always encourage others to challenge this thought and [smbakeryt]’s milestone. Similarly, DOOM has a history of running on machines far below the original recommended minimum system requirements, and one of our favorites was getting it to run on the NES.

Continue reading “Zork Running On 4-Bit Intel Computer” →