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stranger_vnr 6Mar2011 11:12

Operating system questions..
 
Hii guys,
plzz help me with these questions.
if u are sure of any answer...kindly share it..
thanks in advance
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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