Thread: CPU burst time

  1. #1
    Registered User hermit's Avatar
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    CPU burst time

    Im currently doing Operating system concepts. just a few concepts that i wanna debate on, and have a better understanding

    What is your understading of CPU burst time. In process scheduling there is CPU BURST TIME! how can there be any burst time even before it is process? am i making sense? or rather burst time is just an assumption of how long a process would take? Which part of the operating system, predict the CPU burst time for process schedulling?

    -hermit-

  2. #2
    aurė entuluva! mithrandir's Avatar
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    The whole notion of process scheduling is the very basis for multitasking. Process execution consists of a cycle of CPU execution and I/O wait. Process execution starts off with a CPU burst. This is followed by what is known as an I/O burst, which is follwed by another CPU burst, then by an I/O burst, and so on and so forth.

    There is no burst time for a process, before a process is started. That would be like ordering a cake for a birthday party, and not knowing how many people would be there - how could you be sure that there would be enough to go round (or too much)?

    >>rather burst time is just an assumption of how long a process would take?<<

    An I/O bound process would in reality have a very small burst time, however, a CPU bound process would have a long burst time. So, to a degree it is an assumption based upon the type of process.

    Check out the book "Operating Systems Concepts" by Silberchatz and Galvin - they have an excellent chapter on CPU scheduling.

  3. #3
    Registered User hermit's Avatar
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    Thanking you for that steath.

    Anyway im required to do write a bash shell in UNIX. and i have no idea how to implement it . .

    TROUBLE

    what about the 3 algorithms of process sync? we dont actually implement it , in real life do we? those algoritms are for process sync without OS and hardware . . . im so lost, u cant believe it
    Last edited by hermit; 08-23-2002 at 06:04 AM.

  4. #4
    Refugee face_master's Avatar
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    Yay! Pure Aussie thread!

  5. #5
    Registered User hermit's Avatar
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    Hahha go MAGPIES!

  6. #6
    aurė entuluva! mithrandir's Avatar
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    >>Anyway im required to do write a bash shell in UNIX. and i have no idea how to implement it . .<<

    Did you perhaps mean you have to write a bash shell script? Why would they make you write a shell?

    >>what at about the 3 algorithms of process sync? we dont actually implement it , in real life do we? those algoritms are for process sync without OS and hardware . . . im so lost, u can believe it<<

    We used a language called BACI and wrote programs to simulate process synchronisation. It was pretty easy.

    edit...UP THE MIGHTY LIONS!

  7. #7
    Registered User hermit's Avatar
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    yeah bash shell script it is . .

    the problem is, we are studying all these theories at uni, and all the sudden im required to do programming and write scripts . .

    just tough , i mean for me

    -hermit-

  8. #8
    Refugee face_master's Avatar
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    GO THE DRAGONS! (right sport?)

    //EDIT: i'm talking bout leage

  9. #9
    Registered User hermit's Avatar
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    GET SOME AUSSIE SPIRIT IN HERE

    AUSSIE AUSSIE AUSSIE OI OI OI . .

  10. #10
    Refugee face_master's Avatar
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    AUSSIE AUSSIE AUSSIE !! ...

  11. #11
    5|-|1+|-|34|) ober's Avatar
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    Originally posted by hermit
    what about the 3 algorithms of process sync? we dont actually implement it , in real life do we? those algoritms are for process sync without OS and hardware . . . im so lost, u can believe it
    Process sync is part of any OS, but you'll find that the algorithms that you're probably studying are either outdated, or most times, just theory. There has to be some kind of syncronization, otherwise efficiency would suck... err... in so many words.

    Which algorithms are you talking about? I just took a course in Op Sys Concepts 2 months ago... I think there were more than 3, if I remember correctly.

    Also, I too had to write a shell for Unix... I got the basics down... running programs with options and such, but I never got redirection working. The basic functionality is there, however. OH, I even got background processes to run too

    If you want to see what I did, let me know... I'll try to post the C code tonite when I get home.
    EntropySink. You know you have to click it.

  12. #12
    Refugee face_master's Avatar
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    Damn you Ober!! DAMN YOU!! You ruined the only Aussie (hence the best ) thread on this board!! DAMN YOU!!
    Last edited by face_master; 08-23-2002 at 06:23 AM.

  13. #13
    5|-|1+|-|34|) ober's Avatar
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    oh, you just have to write a script??!?! That's easy! I could send you an example of one of those too
    EntropySink. You know you have to click it.

  14. #14
    5|-|1+|-|34|) ober's Avatar
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    Originally posted by face_master
    Damn you Ober!! DAMN YOU!! You ruined the only Aussie (hen best ) thread on this board!! DAMN YOU!!
    ehh... just tryin to be helpful
    EntropySink. You know you have to click it.

  15. #15
    Refugee face_master's Avatar
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    DAAAAAAAAAAAMN YOOOOOOU OBER!!!

    *starts sobbing*

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