I think that in order to answer this question, we have to consider all the components that are inside the computer PC and analyze individually the input and output of each of these components. And then look at the big picture. I haven't taken the computer architecture course yet, therefore I don't have much idea about the architecture so that I can analyze the outputs from each components like HDD, RAM, processor, input and output peripherals.
I have a doubt, MATLABdude said about setting up an alarm clock and this alarm clock is going to respond by making a sound, I tend to think of it as just software oriented thing. I agree that we are setting up some time in the alarm clock so that it responds on that particular time, but I think of it this way, when the clock goes-off, the signal that you get from the software is just a present state input rather a future state input. We have just programmed the software to respond and give the signal to the speaker on that particular time in the future. I don't think it qualifies to become a future state input. (When I say input, it's just a signal.) Because all the processes are going on in the computer the way it is designed to process. There is no artificial intelligence in a computer PC. I think there should be another parameter which is missing, which will help us define what future state input can be. I mean what condition/scenario satisfies to qualify the signal as a future state input.
On the other hand,
We can call the input signal as future state input when you know everything about the future signal or you don't know anything about the future signal, like, things like, the time on which this input signal is going to come to the input terminal of the device, the frequency of this input signal, or the amplitude. We might know all of these parameters or none of them.
What do you guys have to say about this?