Correct Answer: In a multiprocessor system there exist several caches each may containing a copy of same variable A Then a change in one cache should immediately be reflected in all other caches this process of maintaining the same value of a data in all the caches s called cache-coherency

Correct Answer: Responsiveness Resources sharing Economy Utilization of multiprocessor architectures

Correct Answer: diskcopy

Correct Answer: Logical address space is generated from CPU; it bound to a separate physical address space is central to proper memory management Physical address space is seen by the memory unit Logical address space is virtual address space Both these address space will be same at compile time but differ at execution time

Correct Answer: Fragmentation occurs in a dynamic memory allocation system when many of the free blocks are too small to satisfy any request External Fragmentation: External Fragmentation happens when a dynamic memory allocation algorithm allocates some memory and a small piece is left over that cannot be effectively used If too much external fragmentation occurs, the amount of usable memory is drastically reduced Total memory space exists to satisfy a request, but it is not contiguous Internal Fragmentation: Internal fragmentation is the space wasted inside of allocated memory blocks because of restriction on the allowed sizes of allocated blocks Allocated memory may be slightly larger than requested memory; this size difference is memory internal to a partition, but not being used

Correct Answer: 1) ability to support multiple processors 2) virtual storage 3) source level debugging

Correct Answer: A shell is an interactive user interface to an operating system services that allows an user to enter commands as character strings or through a graphical user interface The shell converts them to system calls to the OS or forks off a process to execute the command System call results and other information from the OS are presented to the user through an interactive interface Commonly used shells are sh,csh,ks etc

Correct Answer: FALSE

Explanation:

It is used to get parent process identifier

Correct Answer: When a program forks and the child finishes before the parent, the kernel still keeps some of its information about the child in case the parent might need it ? for example, the parent may need to check the child?s exit status To be able to get this information, the parent calls `wait()?; In the interval between the child terminating and the parent calling `wait()?, the child is said to be a `zombie? (If you do `ps?, the child will have a `Z? in its status field to indicate this)

Correct Answer: FALSE

Explanation:

The PS command prints the process status for some or all of the running processes