50th Anniversary of the Mechanical Mouse

On December 5th, 2016, some German organisations hold a colloquium at the University of Stuttgart, Germany on the 50th anniversary of the mechanical mouse.

Therefore, the colloquium not only featured the museum director, owner, and guide of his Mouse Museum (cringely called Mouse-oleum, I swear!), a part of the small Computer Museum at the University of Hamburg, Prof. Heinz Oberquelle.

But also the developer of the German claim to mouse history fame, Rainer Mallebrein, and a very early user of it (and its accompanying terminal), Prof. Rul Gunzenhäuser.

The object in question is the (internationally extremely unknown, and even in Germany only 2009 re-surfaced) “Rollkugel” (roll ball) Telefunken RKS 100-86 as an optional acessory to their vector graphics terminal SIG 100-86.


The story as told by Rainer Mallebrain goes like this. In the 1960s Telefunken (funded 1903, merged 1967 with AEG, something like the German General Electric) developed a vector graphics terminal to go with their TR440 Mainframe computer for the German Air Traffic Control. In order to let the traffic controller select the depicted planes directly, different interaction methods were discussed. A light gun like in the 1950s SAGE system seemed not to be ergonomical enough. So, the developers used a track ball (which preceded the invention of the mouse by 20 years). Telefunken now wanted to produce a “civilian” version of the graphics terminal (called SIG-100), especially for the (German) universities who already owned TR440 computers. The problem was that the universities were quite unwilling to use track balls because these devices were quite huge by today’s standards and required to drill a large hole into desks to accomodate them. So the Telefunken developers, just for that purpose, developed a device that also contained a (smaller) ball but could be moved on the desk: a mouse. This mouse was not called a mouse because there was no such concept at the time. In good German engineering tradition, the device was given an accurate, correct, and completely un-inspiring name: the roll ball or Rollkugel.

The Rollkugel (as dissected by a project at the University of Stuttgart that created a replica of the Rollkugel) does not contain any electronics, only two rotational sensors, the ball, a button, and some mechanics. The electronics that aimed at converting the electrical signals into a mouse position was contained in the terminal (which, in turn, was a not so small computer). The mouse cable was not coming out of the Rollkugel at the now traditional 12 o’clock, but at the 6 o’clock position. The Rollkugel was large (about the size of a halved grapefruit), and exactly half a sphere with the button at the top.

Prof. Gunzenhäuser (one of the first computer science professors in Germany) then talked about what they did with the Rollkugel in these early days. He explained that it took a while before the Rollkugel worked without errors. He recalled the first use of the Rollugel in his group was the development of a graphical chess system where the user could move the pieces using this device.

The Rollkugel was sold from 1968 which would make it 48 as of today, but the (not completely serious) explanation for the 50th anniversary was that they worked on it from 1966 on. It is not claimed that this is the first mouse (as Doug Engelbart’s mouse using two wheels) probably was developed earlier.


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