Games - Graphical Environment Manager

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	Games - Graphical Environment Manager

GEM (Graphical Environment Manager) was a windowing system created by Digital Research, Inc. (DRI) for use with the CP/M operating system on the Intel 8088 and Motorola 68000 microprocessors. Later versions ran over DOS as well.

GEM is known primarily as the graphical user interface (GUI) for the Atari ST series of computers, and somewhat less well known as the operating system for a series of PC-like computers from Amstrad. It was also the core for a small number of DOS programs, the most notable being Ventura Publisher. It was ported to a number of other computers that previously lacked graphical interfaces, but never gained popularity on those platforms. DRI also produced FlexGem for their FlexOS realtime operating system.

History

GEM started life at DRI as a more general purpose graphics library known as GSX (Graphics System eXtension), written by a team led by Lee Lorenzen who had recently left Xerox PARC (birthplace of the GUI).

GSX consisted of two parts: a selection of routines for common drawing operations, and the device drivers that are responsible for handling the actual output (the former was known as GDOS and the latter as GIOS, a play on the division of CP/M into machine-independent BDOS and machine-specific BIOS
). GSX was intended to allow DRI to write graphics programs (charting, etc.) for any of the platforms CP/M would run on, a task that would otherwise require considerable effort to port due to the large differences in graphics hardware (and concepts) between the various systems of that era.

GSX evolved into one part of what would later be known as GEM. Originally to be known as Crystal as a play on an IBM project called Glass, the name was changed to Gem. The use of the acronym evolved later (see backronym).

GSX became the GEM VDI, responsible for basic graphics and drawing. VDI also added the ability to work with multiple fonts and added a selection of raster drawing commands to the formerly vector-only drawing set. VDI also added multiple viewports, a key addition for use with windows. A new module, GEM AES (Application Environment Services), provided the window management and UI elements, and GEM Desktop ran on both to provide a Mac-like GUI. The 8086 version of the entire system was first demoed at the November 1983 COMDEX, and shipped in the spring of 1984, now known as GEM/1.

At this point Apple Computer sued DRI in what would turn into a long dispute over the "look and feel" of the GEM/1 system, which was in fact an almost direct copy of the Macintosh. This eventually led to DRI being forced to change several basic features of the system. While Apple would later go on to sue other companies for similar issues, they lost all such cases in the future.

The resulting "lawsuit friendly" GEM/2 allowed the display of only two fixed windows on the "desktop" (other programs could do what they wished however), changed the trash can icon, and removed the animations for things like opening and closing windows. It was otherwise similar to GEM/1, but also included a number of bug fixes and cosmetic improvements.

The last commercial release was GEM/3 which had speed improvements and shipped with a number of basic applications. Commercial sales of GEM ended with GEM/3, the source code was subsequently made available to a number of DRI leading customers.

GEM/4 included the ability to work with Bézier curves, a feature still not common outside the PostScript world. The version was produced specifically for Artline a drawing program from CCP. The system also included changes to the font management system, which made it incompatible with the likes of Timeworks Publisher.

Another version of GEM called GEM/5 was produced by GST for Timeworks Publisher 2.1. It contained an updated look with 3D buttons, font scaling on the fly was included. It came complete with all the standard 3.1 tools. This version was produced from GEM 3.13 with only the Bezier handling moved taken from GEM 4.

At the same time the GEM Desktop itself was spun off as a product known as ViewMAX, which was used solely as a file management shell under DR-DOS. In this form the system could not run other GEM programs. This led to the odd situation where you could have a number of applications (including ViewMAX) all with their own copy of the GEM system inside of them, all taking up memory. Of course this was rare, as there were not that many GEM programs. In these forms GEM survived until DRI was purchased by Novell and all GEM development was cancelled.

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