
Forget the complicated virtual machines and OS installers. Thanks to Slack developer Felix Rieseberg, you can now run Mac OS 8 on a 1991 Macintosh Quadra 900 in a single JavaScript app. The macintosh.js app is available on Github and works on macOS, Windows, and Linux.
Frankly, the idea of emulating a 29-year-old computer within JavaScript is terrible and ridiculous. But like Felix Rieseberg’s Windows 95 emulator, macintosh.js works incredibly well. It works flawlessly with OS 8-compatible software and comes with Oregon Trail, Photoshop 3.0.5, and other apps preinstalled.
“Turning off” macintosh.js from its file directory saves your virtual desktop, so you won’t lose your fancy drawings or word documents. You can even transfer files between your computer and the macintosh.js emulator, or mount a disk to the emulator for a hardcore file-transferring experience.

According to Wikipedia, the Quadra 900 launched with an introductory price of $7,200 in 1991. That’s around $13,600 if you adjust for inflation. Considering that the free macintosh.js comes with a copy of Photoshop 3.0.5, it’s quite a good bargain.
But you may not want to use macintosh.js as your daily driver. It’s a JavaScript app, so it’s naturally clunky and inefficient. And while Netscape Navigator and Internet Explorer come preinstalled in the emulator, they can’t connect to the web or work with modern web pages. (Confident nerds who want to revive Netscape Navigator can play around with the Web Sharing Server inside the emulator.)
Source: Felix Rieseberg via 9to5Mac