Aster CT-80

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The Aster CT-80, an early home/personal computer developed by the small Dutch company MCP (later renamed to Aster Computers), was sold in its first incarnation as a kit for hobbyists. Later it was sold ready to use. It consisted of several Eurocard PCB's with DIN 41612 connectors, and a backplane all based on a 19-inch rack configuration. It was the first commercially available Dutch personal/home computer.[1] The Aster computer could use the software written for the popular Tandy TRS-80 computer while fixing many of the problems of that computer, but it could also run CP/M software, with a big amount of free memory and a full 80×25 display, and it could be used as a Videotext terminal.

Contents

Models

Three models were sold. The first model looked like the later IBM PC (which came on the market years later), a rectangular base unit with two floppy drives on the front, and a monitor on top with a separate detachable keyboard. The second incarnation was a much smaller unit the width of two 5¼" floppy drives stacked on top of each other, and the third incarnation looked like a flattened Apple with a built-in keyboard.

All units ran much faster than the original TRS-80, at 4 MHz, (with a software selectable throttle to the original speed for compatibility purposes) and the display supported upper and lower case, hardware snow suppression (video ram bus arbitration logic), and an improved character font set. The floppy disk interface supported dual density, and disk capacities up to 800 KB, more than four times the capacity of the original TRS-80. A special version of NewDos/80, (an improved TRS-DOS compatible Disk operating system) was used to support these disk capacities when using the TRS-80 compatibility mode.

For the educational market a version of the first model was produced with a new plastic enclosure (the First Asters had an all-metal enclosure) that also had an opening on the top in which a cassette recorder could be placed. This model was used in a cluster with one Aster (with disk drives) for the teacher, and eight disk less versions for the pupils. The pupils could download software from the teachers computer through a network based on a fast serial connection, as well as sending back their work to the teachers computer. There was also hardware in place through which the teacher could see the display of each pupils screen on his own monitor.

Working modes

The Aster used 64KB of RAM memory and had the unique feature of supporting two fundamentally different internal architectures: when turned on without a boot floppy or with a TRS-DOS floppy, the Aster would be fully TRS-80 compatible, with 48KB or RAM. When the boot loader detected a CP/M floppy, the Aster would reconfigure its internal memory architecture on the fly to optimally support CP/M with 60 KB free RAM for programs (TPA) and an 80 x 25 display. This dual-architecture capability only existed on one other TRS-80 clone, the LOBO Max-80.

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