History of the Gem Desktop Environment

Sometime in 1988, the keyboard of my Sinclair ZX Spectrum 48K was finally broken beyond repair, and I asked my parents for a 128K version of the same computer. Instead, they surprised me with an Atari 520 ST. It was my first real-world experience with a graphical desktop environment, complete with windows, icons, and a mouse.

The ST was an amazing machine, not only compared to my poor old “Speccy” and similar cheap home computers, but even to the IBM PC compatibles in my school’s comp-sci lab, which cost at least twice as much.

Decades later, I decided to learn more about the graphical desktop that ran on the Atari ST - GEM by Digital Research Inc. This post is the result of my modest research project.

Much of my source material comes from the Computer History Museum. If you enjoy the article and feel generous, please consider making a donation to the museum.

Xerox Lone Star

In July 1981, Lee Jay Lorenzen, a recent graduate from Southern Methodist University, began working at Xerox’s Office Products Division in Dallas, Texas 1. He was hired to work on the 16-bit version of the recently released Xerox 820 personal computer (code named Worm, as it was supposed to eat Apple). Once inside Xerox, Lorenzen got access to the Xerox Star, the first commercially available computer with a graphical desktop, inspired by the legendary Xerox Alto workstation.

Impressed by the Star’s capabilities, but not its price, Lorenzen set out to design an 8086-based personal computer that would have similar user interface to the Star’s but with a more reasonable price tag. The prototype was named Lone Star, and Lorenzen made a video 2 to promote it within Xerox.

In a nutshell, the Lone Star was a desktop computer based on Intel 8086 CPU, with 128 KB of RAM, 8 KB of ROM, optional 5.25” floppy drives, and running the CP-M/86 operating system. The interesting part was the graphical desktop environment, which was obviously influenced by the Xerox Star - with menus, a message bar, icons…