Draft:Diagnostic lights

A group of tell-tales showing lights for "brake fluid", "stop lamp" and "check engine"

Diagnostic lights are lights used on consumer or industrial electronics for diagnostic purposes.

History

Blinkenlights on the NSA's FROSTBURG supercomputer from the 1990s

Typical LED pattern of a Thinking Machines CM-5

The bits and digits in the earliest mechanical and vacuum tube-based computers were typically large and few, making it easy to see (and often hear) activity. Afterwards, for decades, computers incorporated arrays of indicator lamps in their control panels, indicating the values carried on the address, data, and other internal buses, and in various registers. These could be used for diagnosing or "single-stepping" a halted machine, but even with the machine operating normally, a skilled operator could interpret the high-speed blur of the lamps to tell which section of a large program was executing, whether the program was caught in an endless loop, and so on.

With rising processor clock rates, increased memory sizes, and improved interactive debugging tools, such panel lights gradually lost their usefulness, though today most devices have indicators showing power on/off status, hard disk activity, network activity, and other indicators of "signs of life".

The Connection Machine, a 65536-processor parallel computer designed in the mid-1980s, was a black cube with one side covered with a grid of red blinkenlights; the sales demo had them evolving Conway's Game of Life patterns.

The two CPU load monitors on the front of BeBoxes were also called "blinkenlights".

This word gave its name to several projects, including screen savers, hardware gadgets, and other nostalgic things. Some notable enterprises include the German Chaos Computer Club's Project Blinkenlights and the Blinkenlights Archaeological Institute.