Developed by: Digital Research Inc.
Launched: 1985
Discontinued: 1988

GEM is a windowing environment from Digital Research for use with the CP/M operating system on Intel 8088 processors and the Motorola 68000 microprocessor.
A DOS version was later released.

It was first released on the Atari ST and was also distributed with a number of IBM PC compatible computers created by Amstrad (PC1512, PC1640, and Sinclair PC200).
It was also the kernel for a small number of DOS programs, the most notable of which was Ventura Publisher.

GEM versions

Year	Ver.
1985	GEM/1GEM/1 had disk drives and a trash can on the desktop, shadows on the title bars, and scroll bar sliders as wide as the scroll bars themselves. It looked too much like the Mac for Apple's liking, and they sued Digital Research.
1986	GEM/2Apple's lawsuit led to a number of visual changes: new window controls, narrower scrollbar sliders, no desktop icons, and no resizing of desktop windows. The API is almost identical to GEM/1. This version shipped with the Amstrad PC1512.
1988	GEM/3GEM/3 looks almost exactly the same as GEM/2; the improvements made primarily relate to support for new font formats. It's also possible to set whether a click is required to activate menus, or whether they simply pop up when the mouse hovers over their titles. GEM 3.1 added support for Bezier curves.
1990	ViewMAX/1A GEM-derived environment for PC released alongside DR-DOS 5.0.
1991	ViewMAX/2Released with DR DOS 6.0.
1992	ViewMAX/3This would have been the graphical environment for Novell's DR DOS 7, but it was never released. It included a file manager with colored icons, movable windows, desktop icons, user-configurable backgrounds, windowed DOS sessions, and a built-in screensaver.