WDR paper computer
The WDR paper computer or Know-how Computer is a "computer" that can be easily assembled from a sheet of paper and individual matches. This allows anyone interested to learn how to program without having an electronic computer at their disposal.
This "computer" served as an educational aid in the field of computer science when electronic computers were not affordable or accessible to anyone. The Know-how Computer was developed by Wolfgang Back and Ulrich Rohde and first presented in the television program WDR Computerclub in 1983. It was also published in German computer magazines mc and PC Magazin.
The "computer" worked on paper. Matches were used as information units. Drawn boxes represented the individual registers. Only five commands were enough to represent all mathematical functions. This paper computer was distributed in over 400,000 copies and at its time belonged to the computers with the widest circulation. An emulation as a program for electronic computers is available on Wolfgang Back's website.
The computer's method of operation is nominally based on a register machine by Elmar Cohors-Fresenborg, but follows more the approach of John Cedric Shepherdson and Howard E. Sturgis in their Shepherdson–Sturgis register machine model.
- "Ein Meilenstein: der Knowhow-Computer" [A milestone: The Know-how Computer]. WDR Computerclub (in German). Westdeutscher Rundfunk (WDR). 2001-02-08. Archived from the original on 2001-03-31.  
- Rohde, Ulrich (1983). "Computer für Anfänger" [Computer for beginners]. mc (in German). No. 5. Munich, Germany: Franzis Verlag. ISSN 0720-4442.
- Back, Wolfgang (2003). "Der Know-how Computer - Ein Computer, der mit Streichhölzern arbeitet" [The Know-how Computer - A computer working with matches] (in German). Archived from the original on 2019-04-05. Retrieved 2019-04-05. 
- Cohors-Fresenborg, Elmar (1977). Mathematik mit Kalkülen und Maschinen [Mathematics with calculī and machines] (in German). Vieweg-Verlag. ISBN 3-528-08381-6.
- Shepherdson, John Cedric; Sturgis, Howard E. (April 1963) [December 1961]. "Computability of Recursive Functions". Journal of the Association of Computing Machinery (JACM). 10 (2): 217–255. doi:10.1145/321160.321170. Retrieved 2019-04-06.
- "Know-How Computer". EduNet Namibia. 2013. Archived from the original on 2014-05-23. 
- Kröger, Chris (2016). "Know How Computer". kroegerama (in German). Archived from the original on 2019-04-05. Retrieved 2019-04-05.