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  • Paging file from RAM help for university. Thanks!

    deucalion0

    Member

    Updated: Oct 26, 2024
    Views: 1.2K
    Hi there all, this is my first post and I an new to this kind of forum! I am kind of forced to ask for help as I have no way of finding my answer through using Google, as this seems a bit complicated.

    Basically my lecturer asked me 5 questions, 3 I think I figured out the other two I need clues as to how to find and learn the information needed I was hoping some clevr helpful person around here might be kind enough to give me a couple of pointers! 😉

    The questions I am stuck on are:

    4. Paging in a virtual memory system allows nearly all contents of RAM to be paged to and from the hard disc. However, there must be some pages that are never swapped to disk. List one example, and give reasons.
    5. Construct a diagram to show the mapping of a 64‐bit virtual address to a physical address of 30 bits with a page size of 64K bytes.

    I work hard at university and aim for A's all the way, and sometimes questions just seem difficult to answer.

    Thanks anyone who takes the time to help me out I really appreciate it!!

    Thanks,

    Ray.
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  • sarveshgupta

    Member • Dec 2, 2009

    Hello Ray Welcome to CE

    Well the two questions really seem difficult.

    I will surely post the answer as soon as I get to know the answer
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  • deucalion0

    Member • Dec 2, 2009

    Thanks for your help!!
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  • faizaan

    Member • Dec 2, 2009

    My point of view is that ,

    Paging in a virtual memory system allows nearly all contents of RAM to be paged to and from the hard disc. However, there must be some pages that are never swapped to disk. List one example, and give reasons ?

    There are some pages related to proper functioning of operating system (i.e kernel)
    that are present in main memory and even the page table that is constructed for paging sometimes reside in main memory so this are some pages which may never be swapped out to disk as doing so will lead to improper functioning of o.s .

    Construct a diagram to show the mapping of a 64‐bit virtual address to a physical address of 30 bits with a page size of 64K bytes ?

    As page size is 64k i.e 2^6* 2^10 we require 16 bits to address each page . So remaining bits out of 64 bits in virtual address i.e (64-16=48 bits ) can be used as page number & remaining bits in physical address i.e (30-16 =14bits ) can be used for page frame no present in main memory.So we can say that there are 2^58 pages in virtual memory of 64k size each out of which 2^14 (may be less) pages can be present in main memory.

    Page no is of 48-bits by mistake i have written 58 in image so pls correct it.

    [​IMG][​IMG][​IMG]


    Pls correct me if i am wrong as i am also studying o.s in my current semester.
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  • deucalion0

    Member • Dec 2, 2009

    Wow #-Link-Snipped-# you really put effort into that answer and I am extremely grateful for your help!
    I am still learning and this seems to be the perfect answer, the diagram is a difficult answer and you done extremely well!

    Thanks again I owe you!

    Ray
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  • faizaan

    Member • Dec 3, 2009

    heyy thanks #-Link-Snipped-# ,

    I think we all are here to help eachother so i look forward to have some more good questions & answers from you.

    Please verify the answer with your lecturer and reply (i.e was it right or wrong).If it was wrong please post the correct answer.
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  • deucalion0

    Member • Dec 3, 2009

    Hey #-Link-Snipped-# how are you? I was hoping you give me permission to use your diagram as a template for my own diagram, I think that yours is pretty perfect and I spent ages trying to make something original, but its just not as good as yours.

    Thanks again for all your help, hopefully one day I can repay the favour!

    Thansk again,


    Ray
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  • Kaustubh Katdare

    Administrator • Dec 3, 2009

    Great job, Faizaan 😀 .

    @deucalion0 - you can repay the favour by helping someone else on CE 😀 . Be active here and inform your friends.
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  • deucalion0

    Member • Dec 3, 2009

    I will remain active here definitely, and keep an eye out for others needing help. I am knowledgeable to a certain level in computing, but paging and RAM I never looked into before, it is a bit much for me to get my head around.

    I hope to be of some use around here soon! 😎

    Cheers,

    Ray
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  • faizaan

    Member • Dec 6, 2009

    sorry for late reply (as internet connection was down)

    Thanks everyone for your appreciation .

    And yes #-Link-Snipped-# feel free to use the diagram anywhere you like.

    thanks Big k ...I will try to always be active and share knowledge with fellow ceans.
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  • rigby

    Member • Dec 8, 2009

    Wow, this has actually really helped me as well. Thanks a lot for that diagram and explanation on those! I happen to also be doing an OS class for one of my <removed> . Maybe we should all ban together and start a help club? 😀
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