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Homework Help: What type of category of systems does a computer PC fall under?

  1. Jun 26, 2011 #1
    Is it a linear system? Casual system? Please explain why and how.
  2. jcsd
  3. Jun 26, 2011 #2


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    This sounds like homework. Nevertheless...

    Neglecting the fact that computers are enormously complex and flexible systems--will computers do preempting or in the absence of user input?

    As for linearity--I think... think... FATAL EXCEPTION #2477: DOES NOT COMPUTE

    EDIT: Okay, a philosophical discussion item: what do you consider as computer input...?
  4. Jun 26, 2011 #3
    No it's not a homework question.
    It doesn't do preempting OR in the absence of user input.
    I don't know what you mean by fatal exception #2477.
    I think the input to the computer is signals from the input peripheral attached to the computer.
  5. Jun 26, 2011 #4
    Please tell me how systems can be categorized mathematically as linear or non-linear system or any other system using transform methods or by any other methods. I am looking for information on signals and systems which can describe any system based upon the output characteristics of the signal when the system is given an input signal.
    Last edited: Jun 26, 2011
  6. Jun 26, 2011 #5


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    To prove linearity one needs to prove for the given f(x), f(a+b)=f(a)+f(b) and c*f(x)=f(cx) hold true.

    So now all you need is a function f(x) to describe a computer. Should be no problem. But please be careful with this question. Its known to lead to FATAL EXCEPTION #2477.

    I am not sure if this is even possible but maybe someone already proved this for a turning machine or some other abstract concept of a computer. So you might try googling for turning machine linearity proofs.
    Last edited: Jun 26, 2011
  7. Dec 16, 2011 #6
    What is Fatal Exception # 2477 ? I don't get any answers from google.com.
  8. Dec 16, 2011 #7
    I think a PC is causal and non-linear, but it could be considered linear depending on the program its running and what its I/O are.
  9. Dec 16, 2011 #8


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    That's supposed to be a joke: neither linearity nor causality apply.
  10. Dec 16, 2011 #9
    how does causality not apply? A PC can create outputs based on inputs from the future?
  11. Dec 16, 2011 #10


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    Well, you could set an alarm to trigger an action, but that's probably semantics. I think the bigger issue is that you can't apply these simple classifications to a computer on its own, irrespective of the programming.
  12. Dec 17, 2011 #11
    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?
    Last edited: Dec 17, 2011
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