ZX Spectrum in the GDR by utz Although the GDR was a leader in the early days of computers, by the 1980s it began to lag far behind, like other countries of the Eastern bloc. Computers produced here were almost never officially sold. mere mortals, and Western ones could only be obtained smuggled or (after 1985) bought at exorbitant prices in currency in "Intershop". Since 1984 in various magazines Many diagrams of amateur computers have been published, but rarely could assemble them due to a shortage of parts. However, there have been a number of ZX Spectrum clones produced in small quantities. The first GDR clone, called GDC1 (Grafik-Display-Computer 1), was developed at TH University Ilmenau (Technical University Ilmenau) in 1985. Like everyone else GDR-ovskie, he used the local version of the Z80 - U880. This one has clone had compatibility problems: the processor was idle during screen drawing time, external devices worked through the chip PIO, not through regular ports, and of course there was no ULA - instead of it there was a pair of GDR chips PIO (U855) and CTC (U857). And in the ROM (EPROM) there was only a 4-kilobyte bootloader, which loaded the operating system from tape. Standard configuration, the machine had 64K RAM, which could be expanded to 256K. The car had several versions,similar to each other. It is unknown how many boards were produced. Until today Only a few survived. Another name for this computer "FDJ-Computer" may mean that it was produced somewhere under under the auspices of the FDJ (Free German Youth, state youth organization). http://www.robotron-net.de/eigenbau.html#GDC Next up was Spectral, also known as EPRO2. It was developed at IFAM (Engineer Office for Applied Microelectronics), Erfurt, in 1987, mass-produced at VEB Mikroelektronik "Karl Marx" and sold through VEB Robotron-Vertrieb, Erfurt, from December 1988 year. The latter company still exists under the name "Hubner-Elektronik", and IFAM still retains the rights to development. This computer had 48K RAM (expandable to 128K) and apparently higher compatibility with the original ZX Spectrum than most other GDR clones. As As a bonus, there was also a joystick port. http://www.sax.de/~zander/zx/spectral.html http://www.robotron-net.de/eigenbau.html#Spectral A few years ago there was a project to recreate a computer Spectral: http://www.sax.de/~zander/zx/spec_nb.html In the same 1987/88, HCX appeared - developed in Magdeburg in Technical University and plant Schwermaschinenbau-Kombinat "Ernst Thalmann" (SKET, Heavy Machinery Combine). It had low compatibility (ULA was simulated by U885 and U887 chips, and the ROM wasmodified), but there were two joystick ports. HCX it was supposed to be mass-produced, but this did not happen. Was 30 boards manufactured by VEB GALVANO in Wernigerode in 1989, they were assembled into finished computers by a local computer club in Magdeburg. No surviving specimen is known. http://www.sax.de/~zander/zx/hcx.html http://www.robotron-net.de/eigenbau.html#HCX Towards the end of the GDR, the AdW Institute - ZKI (Academy of Science of the GDR, Central Institute for Cybernetics and Information Processing) in Berlin released KuBbCh. It was on sale as a kit for self-assembly by the ZWG Center (Center for Scientific Machine Construction) in Liebenwalde. Like GDC, ROM here it was only at 1K or 2K, it only loaded from the tape main OS. But otherwise the car was very compatible with original ZX Spectrum. There were also schemes for expanding ROM up to 16K, so as not to load from the tape. There was a built-in disk drive controller (U8272, NEC upd765/Intel 8272 clone), so it was possible use CP/M. It was possible to connect the computer to the monitor Robotron K7222 and to a regular TV via the antenna input. Before 4 copies survived today, at least exactly so much is known. http://www.sax.de/~zander/zx/kubbCh.html Another ZX clone was produced in Halbleiterwerk-Frankfurt/Oder (Semiconductor Plant Frankfurt/Oder). Little is known about him but the two surviving boards wererestored to working condition. http://www.sax.de/~zander/zx/hfo.html There were even more mysterious clones. The only one even a little documented - "ZX-Jena" (http://www.sax.de/~zander/zx/zxj.html). Another homemade one - BCS 03 (http://www.robotron-net.de/eigenbau.html#BCS). From him There are only a few photos left, but they say that the scheme published in some magazine. You can also read here (in German): http://www.robotrontechnik.de/html/computer/bausaetze.htm * * * > Wow! I've never heard of these clones before! > Loading "ROM" from tape is interesting. I've only seen this before > in ATM Turbo - and even then optional > (more precisely, this was mentioned in the documentation, but about such > I don’t know any copies). It seems that this was typical for the GDR, other computers (not Spectrum clones) were also made with the same bootloader. Perhaps due to economic problems we had enough RAM, but not Large ROMs were enough. Or some ROM programmers do not supported large ROMs. One can only guess about this. utz
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