And this raises the thorny question of what exactly happens, from SkyNet's own point of view, when it sends a unit back into the past.
It powers up the machine, the robot vanishes, and.. then what? Does it actually remember having done that?
Or does it deduce each time that a previous version of it must have done so?
Assuming that it's actual goal was to make humanity extinct, rather than to enslave humanity for its own benefit. The problem for the AI is that if it values its own continuation, it needs to have the means of maintaining and replacing the hardware on which it depends. Who runs the mines, the factories, the shipping, the processing?
Does it have enough robots to do all that? Does it even know how to do all that?