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Gescomp 720 / 730

GESPAC SA was a Swiss company who designed the G-64/96 Bus in 1979. This interface bus concept provides a simple way to interface microprocessor modules with memory and peripheral modules on a parallel bus. The G-64/96 Bus uses a simple, yet modern and powerful interface scheme which allows a higher level of functionality from the single height Eurocard form factor. The low overhead of the G-64/96 Bus interface greatly eases the design of custom boards by the User. This is why, even many years after its invention, the G-64/96 Bus is still widely used in the industry.

The G-64/96 bus concept supports the following features:

- Processors manufacturer independent interface - 8 and 16-bit data transfers - Up to 32 Mbyte addressing capability - Multiple DMA operations - Non-vectored and vectored interrupts - A parallel decentralized arbitration scheme (G-96: multi-processors) - A message passing mechanism (G-96: multi-processors)

In 1982, GESPAC SA released two computers based on the G64 Bus: Gescomp 720 and Gescomp 730, mainly targeted as industrial use.

These modular systems could use a wide variety of G64 compatible boards. They could be powered by a 68000/6809 CPU, or a ZX80 CPU or a 8085 CPU !

Depending on the CPU installed, the computer could run different operating systems:

- 68800-6809 -> GESDOS, offering an editor, macro-assembler, Basic, Graphical Basic, 6809 emulator, IEEE 4888, Centronics printer interface
- Z80-8085 -> CP/M 2.2, mainly used for wordprocessing and CP/M tools
- Z80 -> GESBOS, offering a GESBOL interpreter, GESBOL compilator + many professional applications.

Each computer had 64 KB RAM and came in different mass storage configurations:
- two 5.25'' floppy disk drives (400 KB each)
- two 5.25'' floppy disk drives (800 KB each)
- one 5.25'' floppy disk drive + 5 MB Winchester hard disk

Apparently the computer had a colour graphic card offering 512x256 pixels resolution.

In 1982, GESPAC NETWORK was available. It was a communication network solution for Gespac Bus based systems. Up to 32 computers could be connected, to a maximum distance of 300m and with a transmission speed rate of 800 KB/s.