Yesterday’s Technology, Re-engineered Today

Watching [sprite_tm]’s build of a handheld 486-based gaming computer, we got to thinking about retro computers and the eternal questions of how much of the computer needs to be actually “old” for it it be retro. Where is the soul of a retro computer? The CPU? The old yellowing plastic case? Maybe it depends on what you’re trying to get out of the hobby.

There is of course a spectrum of people playing around with old computers. For some people, let’s call them “vintage computer enthusiasts”, half of the fun is in keeping the actual old hardware running. This group tends to know what teletype lubricant smells like, and how to tell which capacitors need replacing.

For others, “team retro”, the joy is in using the machine itself, whether that be teaching the old dogs new tricks, or simply loading up nostalgic video games. Team retro is more content with emulations or emulations that are wrapped up neatly in hardware workalikes. They know which registers need POKEing, and whether or not Commander Keen is running at the right framerate.

I think [sprite_tm]’s project falls in with yet another camp, the retro-reengineers. Here, the idea is to step through the engineering lessons of the past by re-designing something from a bygone era. So when [sprite_tm] went with a period 486 CPU backed up by a modern FPGA, perhaps ironically borrowing code from the modern MiSTer project, it makes sense for his goals. Retro-reengineers know the bus architecture and the memory timings, and they are reinventing the wheel as a learning experience. Or in the case of [Voja Antonic]’s imaginary four-bit machine, it’s a teaching experience.

How you work often reflects what you’d like to get out of the project, and at Hackaday, of course, we love all of the above! We’ve identified at least three broad schools of fooling around with old computers. Are we missing any?

Hackaday Europe 2026 – Building A Retro PC From Scratch

If you’re big into retrocomputing, you probably spend a lot of time chasing parts and machines on online classifieds or through local swap meets. But what if there was a different way to build a classic retro PC? What if you could put one together from bare chips, from the ground up?

[Jeroen Domburg] is no stranger to the pages of Hackaday. You might know him by his alias, [sprite_tm], under which he’s shared many projects, from miniaturizing old hardware to unearthing the secrets of undocumented commercial hardware. Now, he’s turning his considerable skills to figuring out how to build a retro PC in today’s world, and came to Hackaday Europe 2026 to show us all how it’s done.

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HamsterOS Crams Complete Graphical Desktop Onto 1.44 MB Floppy

It’s not every day that there’s a new OS in the works for 386 and 486-era hardware, but [John Swiderski] let us know he working hard to bring HamsterOS to retrocomputing enthusiasts everywhere.

HamsterOS targets a November 2026 release.

HamsterOS is a tiny but full-featured multitasking 32-bit graphical operating system that fits on a single 1.44 MB floppy disk. It’s designed as a floppy-first OS, but can easily be installed to a hard drive and includes a suite of native applications. There’s even DOS support!

The list of features is impressive, many of which are targeted at making life a little easier for those working with vintage hardware. One example we like is the CMOS crash counter, which automatically forces the system into a basic VGA safe mode after three consecutive failed boot attempts.

Speaking of making vintage computing a little easier to handle, [John] also released HamsterWeazle, a free GUI front-end for Greaseweazle, the open-source USB device that makes interfacing to old floppy drives easy. If you’re finding yourself intrigued by software like HamsterOS but wondering how you’d write to a 1.44 MB floppy without already having some old hardware up and running, Greaseweazle over USB — and HamsterWeazle to make it much more user-friendly — is one way you’d do it.

We recently featured GentleOS, a charming and streamlined graphical OS aimed at vintage hardware that makes a point of showing what’s possible when new ideas meet old hardware. If you have a retrocomputing project you want to show off, custom OS or otherwise, let us know on our tips line!

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

[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”

Why The Latest Linux Kernel Won’t Run On Your 486 And 586 Anymore

Some time ago, Linus Torvalds made a throwaway comment that sent ripples through the Linux world. Was it perhaps time to abandon support for the now-ancient Intel 486? Developers had already abandoned the 386 in 2012, and Torvalds openly mused if the time was right to make further cuts for the benefit of modernity.

It would take three long years, but that eventuality finally came to pass. As of version 6.15, the Linux kernel will no longer support chips running the 80486 architecture, along with a gaggle of early “586” chips as well. It’s all down to some housekeeping and precise technical changes that will make the new code inoperable with the machines of the past.

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A Previously Unknown Supplier For A Classic Chip

It’s common enough for integrated circuits to be available from a range of different suppliers, either as licensed clones, or as reverse-engineered proprietary silicon. In the case of a generic circuit such as a cheap op-amp it matters little whose logo adorns the plastic, but when the part in question is an application processor it assumes much more importance. In the era of the 486 and Pentium there were a host of well-known manufacturers producing those chips, so it’s a surprise decades later to find that there was another, previously unknown. That’s just what [Doc TB] has done though, finding a 486 microprocessor from Shenzhen State Micro. That’s not a brand we ever saw in our desktop computers back in the 1990s.

Analysis of a couple of these chips, a DX33 and a DX2-66, shows them to have very similar micro-architecture but surprisingly a lower power consumption suggesting a smaller fabrication process. There’s the fascinating possibility that these might have been manufactured to serve an ongoing demand for 486 processors in some as-yet-unknown Chinese industrial application, but before any retrocomputer enthusiasts get their hopes up, the chips can’t be found anywhere from Shenzhen State Micro’s successor company. So for now they’re a fascinating oddity for CPU collectors, but who knows, perhaps more information on these unusual chips will surface.

Meanwhile we’ve looked at the 486’s legacy in detail  before, even finding there could still just be 486-compatible SoCs out there.

Kernel Hack Brings Windows XP To The 486

The venerable Intel 486 was released in 1989 as the successor to the extremely popular Intel 386. It was the minimum recommended processor for Windows 98.  (Surprisingly, the Windows 95 minimum was a 386!)  But by the time XP rolled around, you needed at least a 233 MHz Pentium to install. Or at least that was the case until recently when an extremely dedicated user on MSFN named [Dietmar] showed how he hacked the XP kernel so it could run on the classic chip!

The biggest issue preventing XP from working on earlier processors is an instruction introduced on the Pentium: CMPXCHG8B. This instruction compares two 8-byte values and takes different actions depending on an equality test. It either copies the 8 bytes to a destination address or loads it into a 64-bit register. Essentially, it does what it says on the tin: it CoMPares and eXCHanGes some values. If you want to dig into the nitty-gritty details, you can check out this info on the instruction taken from the x86 datasheet.

Without getting too technical, know that this instruction is vital for performance when working with large data structures. This is because one instruction moves 8 bytes at a time, unlike the older CMPXCHG instruction, which only moves a single byte. Essentially, [Dietmar] had to find every usage of CMPXCHG8B and replace it with an equivalent series of CMPXCHG instructions.

On a side note, the once well-known and devastating Pentium F00F bug was caused by a faulty encoding of the CMPXCHG8B instruction. This allowed any user, even unprivileged users, to completely lock up a system, requiring a full reset cycle!

So [Dietmar] was successful, and now you can run the German version of Windows XP on either a real 486 or an emulated one. The installer is available on the Internet Archive and there’s a detailed video below demonstrating installing it on the 86Box virtual machine host.

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