from
Jargon File (4.4.4, 14 Aug 2003)
speedometer
n.
A pattern of lights displayed on a linear set of LEDs (today) or nixie
tubes (yesterday, on ancient mainframes). The pattern is shifted left
every N times the operating system goes through its {main loop}. A
swiftly moving pattern indicates that the system is mostly idle; the
speedometer slows down as the system becomes overloaded. The
speedometer on Sun Microsystems hardware bounces back and forth like
the eyes on one of the Cylons from the wretched Battlestar Galactica
TV series.
Historical note: One computer, the GE 600 (later Honeywell 6000)
actually had an analog speedometer on the front panel, calibrated in
instructions executed per second.
from
The Free On-line Dictionary of Computing (8 July 2008)
speedometer
A pattern of lights displayed on a linear set of LEDs (today)
or nixie tubes (yesterday, on ancient mainframes). The
pattern is shifted left every N times the operating system
goes through its {main loop}. A swiftly moving pattern
indicates that the system is mostly idle; the speedometer
slows down as the system becomes overloaded. The speedometer
on Sun Microsystems hardware bounces back and forth like the
eyes on one of the Cylons from the wretched "Battlestar
Galactica" TV series.
Historical note: One computer, the GE 600 (later Honeywell
6000) actually had an *analog* speedometer on the front panel,
calibrated in instructions executed per second.
[{Jargon File}]