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Thread: Operating system

  1. #1 Operating system 
    New Member
    Join Date
    Mar 2011
    HII guys,
    plzz help me with these operating system questions.

    1 - The purpose of having an instruction format with 2 registers for one operand is:
    a- To allow one register to be on the stack
    b- To use one as a base and the other as an index
    c- To extend the page size
    d- To enhance virtualization
    e- To prevent disturbing the stack

    2 - List the four atomic operations in switching from kernel mode to user mode. Be sure to give the proper settings of ON and OFF values for a switch in the stated direction.
    Set IC, privilege mode off, protection on, interrupts off

    3 - Why does an O/S store the user's registers and/or stack values in low memory?
    a- Because it doesn't need a register to access the memory
    b- Because those locations are reserved for that purpose
    c- Because that's where the user expects them to be
    d- Because it's faster

    4 - A traditional TLB contains :
    a- Recently referenced page #s and frame #s for all processes
    b- Recently referenced page #s and frame #s for only the current process
    c- All page #s and frame #s for the current process
    d- All page #s and frame #s for all active processes

    5 - Given: a 24-bit-maximum memory address size, with 12 of those bits used for a displacement (page offset) to the byte in the page, what is the maximum number of page frames possible on such a machine?
    a- 211
    b- 212
    c- 223
    d- 224

    6 - Linux manages scheduling of tasks by using:
    a- 140 bitmaps and a single priority queue
    b- 1 bitmap and 140 priority queues
    c- 2 bitmaps and 140 priority queues
    d- 140 bitmaps and 2 priority queues

    7 - (10) You are the system manager for DJF systems and you have noticed that when running process X, the CPU is in a 2-instruction loop at REAL address 17,000 (decimal) and REAL address 40,000 (back and forth from one to the other). Given a machine with page-size = frame-size = 4096, use the data below to help you translate these 2 real addresses to virtual addresses (i.e.; address offsets within the process), so you can examine a memory dump of the object module for performance analysis. Remember: Frame #'s & page #ís start at 0.
    Page # Virtual address Frame # Real address range
    0 v0-4095 4 16384-20479
    1 v4096-8191 7 28672-32767
    2 v8192-12287 9 36864-40959
    3 v12288-16383 2 8192-12287

    The translated addresses (the addresses in the looping program module) are:

    8 - Describe the advantages of having multiple state vectors (one per interrupt TYPE). List the TYPES we saw when we discussed the z/390.

    9 - Describe what must happen when an interrupt occurs in ANY machine, in order for the O/S to handle the interrupt properly.

    10 - What is "Optimal Page Replacement" and why can it not be used effectively with interactive programs?

    11 - Describe the paravirtualization concept (hint: Xen is one such implementation).

    12 -VMware provides a mechanism for migrating a running OS from one physical machine to another WHILE the OS and its application are RUNNING. List some of the problems in making this possible. List some limitations.

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  3. #2  
    New Member
    Join Date
    Mar 2011
    thanks for the very nice info.

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  4. #3  
    New Member
    Join Date
    May 2011
    this is nice information.
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