To achieve maximum efficiency and reliability a mode of operation known as symmetric multiprocessing is used In essence, with SMP any process or threads can be assigned to any processor
Operating Systems problems
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1. What are the four layers that Windows NT have in order to achieve independence?
Correct Answer: 1 Increased speed and memory capacity of microprocessors together with the support for virtual memory and 2 Growth of client server computing
3. How are the wait/signal operations for monitor different from those for semaphores?
Correct Answer: If a process in a monitor signal and no task is waiting on the condition variable, the signal is lost So this allows easier program design Whereas in semaphores, every operation affects the value of the semaphore, so the wait and signal operations should be perfectly balanced in the program
Correct Answer: It is a technique proposed by Lamport, used to order events in a distributed system without the use of clocks This scheme is intended to order events consisting of the transmission of messages Each system 'i' in the network maintains a counter Ci Every time a system transmits a message, it increments its counter by 1 and attaches the time-stamp Ti to the message When a message is received, the receiving system 'j' sets its counter Cj to 1 more than the maximum of its current value and the incoming time-stamp Ti At each site, the ordering of messages is determined by the following rules: For messages x from site i and y from site j, x precedes y if one of the following conditions holds(a) if Ti
5. Describe the Buddy system of memory allocation.
Correct Answer: Free memory is maintained in linked lists, each of equal sized blocks Any such block is of size 2^k When some memory is required by a process, the block size of next higher order is chosen, and broken into two Note that the two such pieces differ in address only in their kth bit Such pieces are called buddies When any used block is freed, the OS checks to see if its buddy is also free If so, it is rejoined, and put into the original free-block linked-list
6. What are the key object oriented concepts used by Windows NT?