Aster CT-80

From Academic Kids

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 and a backplane.

Three models were sold. The first model looked like the later IBM PC, a rectangular base unit with two floppy drives on the front, and a monitor on top with a separate keyboard. The second incarnation was a much smaller unit the width of two 5 1/4" 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, and the display supported upper and lower case, and hardware snow suppression (video ram bus arbitration logic). The floppy disk interface supported dual density, and disk capacities up to 800 KB.

The Aster also 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. But when the boot loader detected a CP/M floppy the Aster would reconfigure its internal architecture on the fly to optimally support CP/M with 60 KB free RAM, and a 80 x 25 display. A capability it only shared with the LOBO Max-80 another TRS-80 clone.

With a special configuration tool it could reconfigure its floppy drivers to read and write the floppies of about 80 other CP/M systems.

Most Aster CT-80's (about 10 thousand) were sold to schools for computer education, in a project first known as the "honderd scholen project" (one hundred schools project), but which later involved many more than just one hundred schools. MCP received this order from the Dutch government because their computer met all the demands, including the demand that the computers should be of Dutch origin and should be built in the Netherlands. Later however the Government turned around and gave 50% of the order to Philips and their P2000 homecomputer even though the P2000 did not meet all the demands and was made in Austria.

Aster computers was based in the small town of Arkel near the town of Gorinchem. Initially Aster computer b.v. was called MCP (Music print Computer Product) and was specialised in producing computer assisted printing of sheet music. They started selling electronc kits to hobbyists. Among those kits were alternative floppy disk drives for TRS-80 computers. Because the infamous TRS-80 expansion interface was very expensive they also developed their own alternative in the form of a floppy disk controller and printer interface that could be built right into the floppy disk enclosure. The lack of RAM expansion was solved by a service in which the 16 KB RAM chips would be replaced by 64 KB ram chips. While this went on MCP renamed itself to MCP CHIP but ran into problems with the German computer magazine CHIP, and had to return to its former name. At that time MCP did also sell imported home computers like the TRS-80, and the Apple.

After designing their own fully functional replacement for the TRS-80 expansion interface (which was never commercialised) the company decided that the TRS-80 was a great computer but it lacked in several areas. The display logic and resulting display 'snow' was bothersome, the CPU speed could be improved, and the floppy disk capacity and reliability was low. Also the more interesting software offered for CP/M systems was lacking. So they decided they could do better and designed the Aster CT-80.

Soon the little shop became too small and they moved to a much larger factory building nearby, and started mass producing the Aster for a period of a few years.

To enhance and modernise the Aster CT-80 the company also designed three alternative video display adapters to supplement or replace the TRS-80 compatible video card.

  • A very High resolution monochrome video card with blitter and hardware line drawing capability.
  • A colour video card with sprite capability based on the same video chip (the TMS9918) as the TI99/4 and MSX computers.
  • A color video card that had high resolution capability because it could reprogram the character set of the 80 x 24 display and could provide a separate programmable character for all of the 1920 (80 x 24) characters on the screen. Because the characters were 8 x 12 pixels this would allow for a resolution of 640 x 288 pixels, which was quite high for the time. This video card also supported 16 foreground and 16 background colors per character (one byte per character position).

A hard disk interface was also in the works.

Finally a replacement for the aging Z80 processor was also being developed in the form of an Intel 8086 board, and 16 bit memory boards.

Such replacements of main system components were possible because of the fact that the Aster CT-80 was designed to use a backplane that supported 8 and 16 bit processors, and used the modular Eurocard design.

Unfortunately none of these extensions to the system became available because the company folded before they came to fruition.

Perhaps the Aster computer inspired another Dutch computer firm to name their computer after another typical Dutch flower — the Tulip.

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