Remember when Windows 98 needed a computer costing $1,000+ to run comfortably?

Almost 20 years later, the early Microsoft OS runs on a computer that sells for just $25 and that is so small it fits on your wrist.

This Raspberry Pi-powered, Windows 98 wristwatch is a project by amateur technology enthusiast 314Reactor.

With a charming homemade look, the wristwatch uses tape and Sugru moldable glue to bind the Raspberry Pi Model A+ — the B+’s smaller and less powerful brother — to the attached touchscreen, battery, switch and power converter.

SEE: Raspberry Pi Zero W: Hands-on with the $10 board

To get the venerable OS running on the Pi’s ARM-based hardware, 314Reactor used the open-source machine emulator QEMU, which provides a virtual Intel 486 machine. He used his own copy of Windows 98, from which he extracted the necessary .img file.

Full instructions for building the watch are available here, along with much of the code needed. Adding the necessary hardware to the Pi was described as “relatively painless” by 314Reactor, provided you have experience hooking up electronics to the Pi’s general-purpose input/output (GPIO) pins.

As impressive as it is to run the OS on such a cheap computer, performance is rather sluggish, with 314Reactor overclocking the speed of the Pi’s CPU to 800MHz to boost its responsiveness.

If Windows 98 doesn’t prick your interest, then there are plenty of other classic Windows OSes you can run on the Pi.

Below is Windows 3.1, 95, and the recently departed XP, all running on the Raspberry Pi.

While the heavy toll of emulation slows the performance of most of these operating systems, Windows 3.1 seems to run as well as it did on computers costing hundreds of dollars in the early 1990s.

Running these emulations on the Raspberry Pi 3 Model B, the most recent and most powerful Pi, also appears to help a lot, with even XP seemingly just about useable on the Pi 3.

If you’ve got a Raspberry Pi and an old copy of Windows knocking around, then here’s what you need to do. Instructions for Windows 3.1 are available here, for Windows 95 here, for Windows 98 here and Windows XP here.

Last week the Raspberry Pi Foundation launched its latest board, the Raspberry Pi Zero W, a $10 computer that adds Wi-Fi and Bluetooth connectivity to the tiny Raspberry Pi Zero.

Windows 3.1

Windows 95

Windows XP

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