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Cynosure-EPR

How do I figure out how many pages of each page size exist? Page size: 512, 1024, 2048 (words) Number of frames allocated to the process: 4, 8, 12 There is a list of 3001 memory addresses that need to happen, but I can't really start until I figure out how many total page numbers exist.

  • one year ago
  • one year ago

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  1. A.Avinash_Goutham
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    i thot page size is fixed for a system.....is it not?

    • one year ago
  2. A.Avinash_Goutham
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    and wat do u mean by 3001? the memory size is 3001?

    • one year ago
  3. Cynosure-EPR
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    I think it is. This is simply a "virtual system" and the page sizes should still be fixed. However, with a page size of 512 you will have a certain number of pages, and with a page size of 1024 you will have half as many pages. I have 3001 "virtual addresses". I believe this means there are 3001 accesses to memory. The amount of memory in the system is unknown which is why I can't seem to figure out the number of pages. It may very well be the size of memory, but that's not what it says.

    • one year ago
  4. Cynosure-EPR
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    http://www.cs.odu.edu/~mukka/cs471f12/project/Projectspec.pdf : (it's problem 2). I can do the coding stuff, but I'd like to know how many pages of each page size exist before I get started. http://www.cs.odu.edu/~mukka/cs471f12/project/testfile.dat : Here is a list of the 3001 virtual addresses (though I doubt it would be of help in finding the number of pages.. and if it does then I am completely off with my thoughts)

    • one year ago
  5. A.Avinash_Goutham
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    yeah it's like the range of those addresses...........so i think u can get a lower bound on the size of memory

    • one year ago
  6. A.Avinash_Goutham
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    and u got to repeat this thing with each page size............. so consider the 512 size case....

    • one year ago
  7. Cynosure-EPR
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    Ahh, okay. That means I'm going to have to code a program to figure out the range of all those addresses. I guess I can try to do it without the range just by diving each memory address by the page size, dropping the remainder, and adding one. I just would have felt more comfortable knowing the number of pages so I could draw it out on paper before I start coding.

    • one year ago
  8. A.Avinash_Goutham
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    um i wonder if u need the total number of pages.............like say the max mem address is round 90000 and memory size occurs in powers of two(generally....well u can allot any size to a vm) and say u fix the size of page to be 512..........so the number of pages depends on the size of memory u give and if u want a page fault sitaution i think u should give a memory less than that like 90000 so there should some swaps and stuff........so it depends on the memory u give to this virtual machine?

    • one year ago
  9. Cynosure-EPR
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    I don't *need* the total number of pages. It would just help me draw it on paper before I started coding so I could be 100% sure of the results and not have to guess as I'm writing. You were correct before though with the amount of memory being the range of the memory locations. There would be no point in giving this virtual machine more memory than that range as it wouldn't use it.

    • one year ago
  10. A.Avinash_Goutham
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    no i meant some thing like faar less than the range of the memory addresses............u want to observe the demand paging concept r8..........so if u give enough memory there would be no page fault? so..........so no virtualisation?

    • one year ago
  11. Cynosure-EPR
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    I don't think I'm allowed to just make up an amount of memory. That would make my answers different from everyone elses' in the class which would be impossible to grade. I think using the entire range of memory would still allow for page faults as there are only 4, 8, and 12 frames. So, if I had 4 frames and used one to put something in that frame would be considered used (even though there is still a lot of empty memory in it) and there would only be 3 frames left to place to put something in. This would cause 4 page faults for the first four entries for sure. It's obviously not efficient, but that's my best guess. What do you think?

    • one year ago
  12. A.Avinash_Goutham
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    i was thinking something like there are 24 frames in total........so like if memory size is like 24*512*sizeof(word).......there would be no page fault? so smthin like 60-70% of that size? that's wat i was thinking.....and i dont might do if u are not allowed to make up the amount of memory

    • one year ago
  13. A.Avinash_Goutham
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    *dont kno wat u might

    • one year ago
  14. Cynosure-EPR
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    I see what you're saying but I'm pretty sure it's not allowed. However, there are only 4 frames for one problem, 8 for the next, and 12 for the next. So, with the entire range of memory from that list of memory locations you would have enough memory but the frames would be allocated so you can't use it all which would give us page faults. I think that's the correct solution.

    • one year ago
  15. A.Avinash_Goutham
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    ok may be.......... i think u shud check it out.........

    • one year ago
  16. Cynosure-EPR
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    I will try!

    • one year ago
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