website/content/museum/buromaschinenwerke-zella-mehlis-cellatron-8205.md

title, categories, types, origins, years, cpus, params

title	categories	types	origins	years	cpus	params
BÜROMASCHINENWERKE ZELLA-MEHLIS Cellatron 8205	Computers	Professional Computer	Germany	1963	Discrete components	name image company company_name specs tabs forum_thread photos oc_id source Cellatron 8205 /media/museum/photos/veb_8205_system_s1.jpg /companies/buromaschinenwerke-zella-mehlis BÜROMASCHINENWERKE ZELLA-MEHLIS label value NAME Cellatron 8205 label value MANUFACTURER Büromaschinenwerke Zella-Mehlis label value TYPE Professional Computer label value ORIGIN Germany label value YEAR 1963 label value BUILT IN LANGUAGE None label value KEYBOARD Primary keyboard label value CPU Discrete components label value SPEED Unknown label value RAM 4096 x 33 bits on magnetic drum memory label value ROM None label value TEXT MODES No display but lamp array label value SIZE / WEIGHT required space: approx. 9 square meters label value BUILT IN MEDIA 2 paper tape punchers, 1 paper tape reader label value OS No OS label value POWER SUPPLY 1500 VA power consumption label value PRICE Unknown photos 1002 title subtitle text image LARGE VIEW /media/museum/photos/veb_8205_system_s2.jpg title subtitle text image MAGNETIC DRUM 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. /media/museum/photos/veb_8205_drumdiagram_s1.jpg title subtitle text image PS 2 MANUAL COVER 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.* /media/museum/photos/veb_8205_ps2manual_s1.jpg title subtitle text image BLOCK DIAGRAM #1 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 /media/museum/photos/veb_8205_blockdiagram_s1.jpg title subtitle text image BLOCK DIAGRAM #2 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 /media/museum/photos/veb_8205_blockdiagram_s2.jpg 1028 url date https://web.archive.org/web/20221205112301/http://www.old-computers.com/museum/computer.asp?c=1028 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 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.