--- title: BÜROMASCHINENWERKE ZELLA-MEHLIS Cellatron 8205 categories: - Computers types: - Professional Computer origins: - Germany years: - '1963' cpus: - Discrete components params: name: Cellatron 8205 image: /media/museum/photos/veb_8205_system_s1.jpg company: /companies/buromaschinenwerke-zella-mehlis company_name: BÜROMASCHINENWERKE ZELLA-MEHLIS specs: - label: NAME value: Cellatron 8205 - label: MANUFACTURER value: Büromaschinenwerke Zella-Mehlis - label: TYPE value: Professional Computer - label: ORIGIN value: Germany - label: YEAR value: '1963' - label: BUILT IN LANGUAGE value: None - label: KEYBOARD value: Primary keyboard - label: CPU value: Discrete components - label: SPEED value: Unknown - label: RAM value: 4096 x 33 bits on magnetic drum memory - label: ROM value: None - label: TEXT MODES value: No display but lamp array - label: SIZE / WEIGHT value: 'required space: approx. 9 square meters' - label: BUILT IN MEDIA value: 2 paper tape punchers, 1 paper tape reader - label: OS value: No OS - label: POWER SUPPLY value: 1500 VA power consumption - label: PRICE value: Unknown tabs: - photos forum_thread: 1002 photos: - title: LARGE VIEW subtitle: '' text: '' image: /media/museum/photos/veb_8205_system_s2.jpg - title: MAGNETIC DRUM subtitle: '' text: The magnetic drum memory rotated at 18,000 rpm. It was organised in 128 tracks with 32 sectors each, every track having a read/write head of its own. In total, this resulted in a capacity of 4096 words of 33 bits. image: /media/museum/photos/veb_8205_drumdiagram_s1.jpg - title: PS 2 MANUAL COVER subtitle: '' text: |- Full reference of this book:\ *Gerd Ehrke et al. "Problemorientierte Programmierung für den Kleinrechner C 8205: Die algorithmische Sprache PS 2". Verlag Die Wirtschaft, Berlin.* image: /media/museum/photos/veb_8205_ps2manual_s1.jpg - title: 'BLOCK DIAGRAM #1' subtitle: '' text: |- Block diagram of the central unit. German to English translation:\ Hauptspeicher - main memory\ Operand - operand\ Adressenwähler - address selector\ Akkumulator - accumulator\ Ergebnis - result\ Rechenwerk - arithmetical unit\ Befehlsregister - command register\ Adressregister - address register\ Operationsregister - operation register image: /media/museum/photos/veb_8205_blockdiagram_s1.jpg - title: 'BLOCK DIAGRAM #2' subtitle: '' text: |- Block diagram of the complete system. German to English translation:\ Tastatur - keyboard\ Schreibwerk - printer\ Lochbandleser - paper tape reader\ Lochbandstanzer - paper tape puncher\ Kanal - channel\ Zentraleinheit - central unit\ Rechenwerk - arithmetical unit\ Leitwerk - control unit\ Trommelspeicher - drum memory\ Stromversorgungseinheit - power supply unit image: /media/museum/photos/veb_8205_blockdiagram_s2.jpg oc_id: 1028 source: url: https://web.archive.org/web/20221205112301/http://www.old-computers.com/museum/computer.asp?c=1028 date: '2022-12-05' --- In 1963, engineers at the *Institut für Maschinelle Rechentechnik* (institute for machine computation technology) in Dresden, GDR (ex-Eastern Germany) finished the **D4a**. The D4a had been developed on the basis of the *Kleinrechenautomat Dresden 1* (D1) from 1956. The system was then manufactured by the *VEB Büromaschinenwerk Zella-Mehlis* in three versions, under the name **Cellatron 8201**, **8205**, and **8295 Z**. About 3000 exemplars were produced. The D4a is seen as the **first PC of the GDR**. By the way, VEB is short for *Volkseigener Betrieb* and means as much as "factory belonging to the people". The **C 8205** central unit was comprised of the *Leitwerk* (instruction counter, instruction register, and address decoder), the *Rechenwerk* (accumulator and math operations), and the *Trommelspeicher* (magnetic drum memory). The former two subsystems were realised as discrete circuits including approximately 400 transistors and 2000 diodes. Working memory was realised with a magnetic drum memory providing 4096 words of 33 bits. Moreover, the system was comprised of a command desk with keyboard, lamp array for displaying operational states, switches for locking certain tracks of the drum memory, two paper tape readers and one puncher, and a typewriter-like printer. It needed about 9 sqm space in an air conditioned and noise insulated room. Power consumption was 1500 VA. The system could be programmed in pure machine code, or in interpreted pseudo-code using a program called **GIPS I**, *Gleitkomma-Interpretationssystem einfacher Wortlänge*, i.e. floating point interpretation system with single word length. It simulates floating point arithmetics as well as a number of pseudo data registers. The GIPS I interpreter had to be read into memory before use. Moreover, it was possible to program the system in **PS 2**, which probably meant *programming language 2*. It was developed by VEB engineers. This language implemented various data types, mathematical operations, I/O commands, and control statements equivalent to GOTO, IF...THEN GOTO, labels, subroutines, and FOR-loops. The source program had first to be punched on paper tape, and then compiled. As the PS 2 compiler occupied the complete memory, the resulting object code (in GIPS I format) was immediately punched out on paper tape. After that, the object code could be read and run with the GIPS I interpreter in memory. The picture shows the C 8205 model. Thanks to **Roman von Wartburg** and his [site](http://retrocomputing.ch/) for information and pictures.
We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.