Atari -  Atari Mega ST (1/2/4)
ata_megaST

Atari Mega ST

Atari ST sales were strong, especially in Europe, where Atari sold 75% of its computers. Germany became Atari's strongest market, with small business owners using them for desktop publishing and CAD.

To address this growing market segment, Atari introduced the ST1 at Comdex in 1986. Renamed the Mega, it includes a high-quality detached keyboard, a stronger case to support the weight of a monitor, and an internal bus expansion connector. A 20 MB hard drive could also be purchased. Initially equipped with 2 or 4 MB of RAM (a 1 MB version, the Mega 1, later followed), the Mega machines could be combined with Atari laser's printer for a low-cost desktop publishing package.

A custom blitter coprocessor improved some graphics performance, but was not included in all models. Developers wanting to use it had to detect its presence in their programs. Properly written applications using the GEM API automatically make use of the blitter.

Atari ST - Brief History

At the Winter Las Vegas Consumer Electronics Show of 1985, the Atari 130ST was introduced. ST stands for Sixteen bit data-bus and Thirty-two address-bus. Atari, after it was bought by Jack Tramiel, originally had contracted the Amiga Corporation to manufacture a 16-bit computer, but the contract was dissolved due to legal issues. Atari then rushed to get a machine out to compete with the release of the Comodore Amiga.

The Atari ST line came with many new features over previous Atari computers:

  • 16 bit processor, 68000 CPU
  • Midi Interface
  • Graphical User Interface OS
  • High graphics resulution in color

The new ST systems came with several dedicated coprocessors that enabled enhanced sound, graphics and memory management:

  • MFP 68901 - Interrupt handler
  • Yamaha YM 2149 - Programable Sound Generator (AY-3-8910 compatible)
  • Shifter - Custom video processor
  • GLUE - Custom Memory Manager (MMU)

The Atari130 was a demonstration only prototype, and never released. Due to it's small memory size, the OS did not function properly and the machine was quickly replaced with the Atari 260ST. This computer came with 512KByte of memory, but due to the large need of the OS (192KByte) and the memory need of the enhanced graphics, only 64KByte of free RAM was left.

The new operating system was called TOS, the Tramiel Operating System. The OS was basically a port of CP/M for the 68000 processor. Also interesting is that the high level TOS calls, called GemDOS, were all compatible with the DOS calls for the PC (DOS INT21h calls).

The GUI was called GEM, which stands for Graphical Environment Mamnager. The OS was provided on disk for the early ST models, which limited the free RAM left, and later it was baked into 6 32KByte ROM chips when the OS was fully finished.

By Atari CPU Motorola 68000 @8MHz Memory 512K RAM Sound 3 wave channels + white noise + PCM Sprites n/a Display 320x200 16 out of 4,096 colors, Genlock support Display Chip BLi Sound Chip Yamaha YM 2149 CPU Class 68000 Developed by Atari
Related Systems
 
Atari 8-bit
 
Atari ST
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Atari  Mega ST (1/2/4)
 
Atari PC
Books & Publications
Programming and other books for the 8-bit Atari line (400/800/XL/XE) of computers.
Books for the Atari ST computers
Magazines & Serials
A.N.A.L.O.G. Atari Newsletter And Lots Of Games
Antic Software and merchandise Catalog, later rebranded to just The Catalog
Antic was a magazine devoted to the Atari 8-bit family of home computers and the 16-bit Atari ST.
Manuals & Catalogs
A collection of technical and service manuals for the Atari 5200 game system.
Software Catalogs for the Atari computers
Software & Game Manuals
A collection of Game Manuals for the Atari 5200 game system.
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