Blinkenlights

Blinkenlights is a hacker's neologism for diagnostic lights usually on the front panels on old mainframe computers, minicomputers, many early microcomputers, and modern network hardware.

The Jargon File provides the following etymology:

This term derives from the last word of the famous blackletter-Gothic sign in mangled mock German that once graced many computer rooms in the English-speaking world. One version ran in its entirety as follows.

This silliness dates back to least as far as 1955 at IBM and had already gone international by the early 1960s, when it was reported at the University of London's ATLAS computing site. There are several variants of it in circulation, some of which actually do end with the word blinkenlights.

Although the sign might initially appear to be in German and uses an approximation of German grammar, it is composed largely of words that are either near-homonyms of English words or (in the cases of the longer words) actual English words that are rendered in a faux-German spelling. As such, the sign is generally comprehensible by many English speakers regardless of whether they have any fluency in German. Much of the humor in these signs was their intentionally incorrect language.

Michael J. Preston recites the gem as being posted above in offices as a warning not to mess with the machine in the first print reference from 1974. The sign is also reported to have been seen on an electron microscope at the Cavendish Laboratory in the 1950s. Such pseudo-German parodies were common in Allied machine shops during and following World War II, and an example photocopy is shown in the Jargon File.

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