The talent technical aptitude provides a 25% stackable decrease to time spent on a computer related tasks.

Is there a rule or guideline somewhere in the rulebook concerning the length of computer related tasks? I've been unsuccessful in locating anything of the sort. If not, I'd encourage a discussion of how people determine time required to complete computer related tasks. Is a typical Computers check in combat (e.g. slicing turret targeting) just a single action in length? What about allocating a number of rounds to complete equal to the number of difficulty dice required by the check?

There's a whole bunch of Talents that cut the time used, but it's left to the GM seemingly to decide how long anything takes...

Making these Talents a bit vague, really.

There's a thread in the rebellion beta forum about this as well, for now it's totally up to the will of the gm. Maybe down the road they'll publish some sample check durations in a gm handbook or something.

I think the difficulty is that in narrative time, it should be very GM fiat-y. Hacking a system could, at a baseline, take a few minutes or a few hours depending on the complexity of the system and its defenses.

Where this comes into a problem is when you have a situation like the trash compactor in Episode IV. You need to be able to set a clear baseline for "how many actions would it take to access the trash compactors and shut them down" and then the Talents would reduce that baseline accordingly.

Obviously hacking into a big system should be very hard or impossible in round-to-round time given how it might need to take hours, but at the same time doing so under fire is a trope and something that will probably come up in game more frequently than not.

A lot of success or a triumph might do the same thing. It would be ok with a challenge setting a number of computer strain you have to damage. There, the talent would make the computer to have 25% less strain point.