Generally when a machine is working we refer to it as "up" and when it's not we say the machine is "down." What is the origin of this?
The machine is up/down is an instantiation of a Metaphor Theme.
English speakers (like all humans) are oriented vertically with respect to a gravitational field, so the
UP/DOWN dimension is significant, and English uses it in a variety of metaphor themes.
These themes include:
The prices are rising/falling.
The stock market’s moving up/crashing.
Turn the volume up/down.
What a downer!
the highest levels
The computer is up/down.
Are you up for some handball?
Rise to the occasion.
He fell down on the midterm.
a rise/fall in performance
He’s got his head in the clouds.
He’s got his feet on the ground.
Come back to earth.
high-level cognitive functions
new heights of abstraction
All of these themes are coherent; that is, we tend to think of them in the same ways (e.g,
LESS, SAD, WEAK, PASSIVE, and
WORSE are all negative evaluations, and vice versa.)
To shut down has been used to describe machines for a long time, per OED:
Mech. To stop or switch off (a device or machine, esp. an engine); to cause to stop working or running. Also absol.
This use is attested as early as 1895:
1895 When shutting down a machine, the load should first be gradually reduced..by easing down the engine.
- G. W. Lummis-Paterson · Management of Dynamos · 1895.
Why shut down? Probably because of earlier meanings related to shutting down a factory or plant, attested in 1877, which itself seems to derive from the idea of "shutting the doors" of a facility. Shut meaning to close and lock is much older, and shut down implies closing and bolting something to a fixed position, which in machinery is generally the off position.
Another explanation comes from the figurative meaning of up and down with regard to whether something is being powered. This figurative sense seems to apply in an OED definition for "up" that also dates back quite far:
Increased in power, force, strength, or vigour; actually blowing; ready for action. Also (in Computing), in working condition. Frequently in phr. up and running.
In an attestation from 1570, the term referred to wind, a precursor to the figurative use with reference to power described above.
The winde was somwhat vp, and it caused the fire to be ye fiercer.
- John Foxe · The first volume of the ecclesiasticall history contaynyng the actes and monumentes of thynges passed..in this realme · Rev. ed, 1570 (2 vols.).
References to wind appeared to be common with this figurative sense, until a reference to a steamboat in 1848:
A Government steamer..lay in the river, with steam up.
- J. Mitchel · Jail Journal · 1848.
Finally, an attestation is given that refers directly to computers, offered in 1978, though this is by no means the earliest date in which people would have referred to computers that are on as "up.":
British Steel's giant private packet-switched network is up—and running successfully.
- Computing · 1976
So to answer the question directly, the terms seem to go back quite far to figurative meanings related to up, down, shut down, etc. that were used to describe mechanical conditions before computers but also applied as computers became a prevalent technology.
It might have to do with start up and shut down, as things done to said computers, and to other machines before them:
How to test this hypothesis, I'm not sure.
- Not working. A computer system is said to be down when it is not available to users. This can occur because it is broken (that is, it has crashed), or because it has been made temporarily unavailable to users so that routine servicing can be performed.
- Computer crash sense is from 1965
To crash or shut down of computers is from the '70s according to The Dictionary of American Slang,
- to fail suddenly : The spacecraft's No 1 computer ''crashed'' or shut down/ computers that can alert a mainframe owner to an impending computer ''crash'' (1970s+ Computer)
Might be a combination of actual design with a metaphorical context behind it.
For example, one possible reason is because of the way lots of switches are made (the kind where you flip it up to turn it on, and flip it down to turn it off):
- a light switch (up is on, down is off)
- switches on some computer boxes (think, desktop computers)
- circuit breaker switches (down means it was tripped)
Combine that with the metaphorical idea in English that "down" is bad:
- somebody who is sleeping or dead is down
- somebody who is standing up might be healthy
- when a soldier gets shot, it's a "man down"
- when a helicopter gets blown up, "the bird is down"
...and you come to the notion that if a machine if off, or not working, then it's "down".
We refer to computers and other machines as being up or down because the creators of these technologies used math and mathematical terminology which is rooted in real world observation. Using the Cartesian coordinate plane as an example, "up" on the "y axis" has a direct correlation to "up" on earth. One might think of the "x axis" as the ground and the "y axis" being oriented to our experience up and down on earth, which is a result of gravity. "Up" is positive and increasing in height. We go "higher" as we go "up". The word usage in question is in relation to increase in(higher) flow, volume, or intensity. Because electricity, being somewhat analogous to water, has been described with such language. Also, electricity is used for light and heat, which are also described as higher and lower as a result of mathematical value terminology.
Examples and further thoughts:
Turn up the heat, turn down the heat, turn up the light, turn down the light, could be referencing gas lamps, then came electric lights and dimmer switches. Also, the sun comes up and it gets brighter, it goes down and it gets darker. Power up, power down, speed up, slow down. An increase in amount is up and a decrease is down. Think higher and lower. High energy, low energy. High pressure, low pressure. Another example is turn up the sound, turn down the sound. Hurry up, calm down.