Up to versus one's responsibility

Question

Can "up to" be used to convey the idea of one's responsibility like in the quoted sentence below:

It is up to the system to set all the needed variables.

Is this usage natural or is there any other way to transmit the same idea? Is “The system is responsible for setting the necessary variables” (as suggested in a comment) better?

Answer 1

Yes it is perfectly natural, and has the meaning you want. Some would regard it as too colloquial for documentation. I would regard it as fine on that scale, but possibly ambiguous, in that it depending on context it might be unclear whether it is saying that the system does set all the needed variables, or whether it should set them.

Answer 2

The word responsible has quite a few acceptable senses. I'm not happy about 'the system is responsible for' [a requisite operation] - it seems to be fusing two distinct senses. Surely, the operators and programmers are responsible for ensuring correct operation at all levels (ie human agency; people are accountable) - though we do say 'computer error was responsible for the distorted results' (ie 'caused the distorted results'). (See http://www.thefreedictionary.com/responsible and the AHDEL footnote on usage.) 'Up to' similarly implies accountability.

The program itself includes instructions to set all the necessary values. or

Instructions to set all the necessary values are included in the program; operators cannot enter values of their own choosing.

... cover the two possible meanings.