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The KC85 ('KC' standing for "Kleincomputer", or "small computer") was a model of microcomputer built in East Germany , firstly in 1984 by Robotron (the KC85/1) and later by VEB Mikroelektronik "Wilhelm Pieck" Mühlhausen (KC85/2, KC85/3 and KC85/4)
Technical information
It was based on the U880 CPU (an East German clone of the Z80), with a clock speed of 1.8 MHz.
There were four versions of the KC 85 series, the KC85/1 by Robotron, which was a completely different system (only the CPU and the name were the same, but later the format of saving the programs on cassettes and the BASIC were also made compatible).
The entire series used a TV as a monitor (by coaxial cable, cinch or RGB) and a cassette recorder as mass storage. The keyboard was reportedly of very poor quality.
The KC85/2 was the first computer made in Mühlhausen and had only capital letters.
Then, the KC85/3 was introduced and this one had a BASIC interpreter in ROM, freeing the user from having to load the BASIC interpreter from a cassette every time. Both systems typically had 16 Kb of RAM, but they were expandable with special modules.
The KC85/4 had 64 Kb of RAM and better graphics capabilities.
All KC-series computers's from Mühlhausen could display graphics at a resolution of 320x256 pixels. But the color possibilities weren't that good (each 4x8-pixel cell had a single foreground and background color).
The KC87 was a better KC85/1 with Basic also in ROM. There was an option for colors (the 85/1 was only black/white), but no real graphics.
The wiring diagrams were openly available and there were also a lot of different (and often homemade) schemes and hardware parts. Different magazines published programs and hardware diagrams and also instructions how-to-build them.
Programming languages
The KC85 could be programmed in Assembler and BASIC (the KC85/2 had to load Basic from a cassette), but it was possible to use different modules (sold by VEB Mühlhausen) and to program in FORTH and PASCAL. The operating system was CAOS (Cassette Aided Operating System). It was very simple (almost a "monitor") and you could run different "system services" like LOAD (load a program), JUMP (run a program from a module) or BASIC (if it was built into the ROM).
In the last years of the GDR, a floppy attachment was produced. It was mainly a whole new KC with 4 MHz and a 5¼" Floppy drive (you could have up to four of them). These were able to run CP/M, which was called MicroDOS. (You had to JUMP from the base system to the floppy system and boot from a floppy - another CAOS or MicroDOS).
hobby projects
There were a lot of different projects for the KC85:
- a new keyboard (the old one was the last cr..)
- RAM-Disk
- interfacew (V.24 and others)
- text systems
- connection to electronic typewriters (like the GDR-product "Erika S3004") as keyboard and printer(!)
- programming language BASICODE (a special Basic-dialect); BASICODE-programs were published in radio
External links
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