Quiz #2

Question 2		True / False	(1 points)
	Question:	An I/O device that uses DMA I/O has no need to interrupt the processor.
		True False

Question 3		Multiple Choice	(1 points)
	Question:	The tendency of execution to involve a number of memory locations that are clustered, i.e., with addresses that are close together is termed _______.
		spatial locality temporal locality recursion hit ratio concurrency

Question 4		Multiple Answer	(1 points)
	Question:	Which of the following kinds of storage are volatile?
		registers cache main memory (RAM) disk tape

Question 5		Multiple Choice	(1 points)
	Question:	When an external device detects an event that requires the attention of the operating system, it _______.
		performs a system call executes a trap instruction waits for the processor to notice sends an interrupt to the processor sends a message to the operator

Question 6		Ordering	(1 points)
	Question:	What is the order of the steps in the processing of a simple interrupt, as explained by Stallings?
		- 1 2 3 4 5 6 7 8 9 CPU loads now PC value, based on interrupt   - 1 2 3 4 5 6 7 8 9 Handler restores old PSW and PC   - 1 2 3 4 5 6 7 8 9 CPU finishes current instruction   - 1 2 3 4 5 6 7 8 9 Handler saves remainder of process registers   - 1 2 3 4 5 6 7 8 9 CPU pushes PSW and PC onto stack   - 1 2 3 4 5 6 7 8 9 Handler restores process registers   - 1 2 3 4 5 6 7 8 9 CPU acknowledges interrupt   - 1 2 3 4 5 6 7 8 9 Controller issues an interrupt   - 1 2 3 4 5 6 7 8 9 Handler processes interrupt

Question 7		Multiple Choice	(1 points)
	Question:	If we were to experimentally measure the performances of memory caches of a given fixed size, with different block sizes, starting with a very small block size (one byte) and working up through very large block sizes (the whole cache as one block), we would expect to see the hit ratio
		first increase, then decrease first decrease, then increase increase steadily decrease steadily remain constant

Question 8		Multiple Answer	(1 points)
	Question:	Which of the following are always true of a subprogram that is reentrant?
		the code can be shared between concurrently executing processes the code is not self-modifying the code does not make use of statically allocated variables the code is not called recursively each activation has its own copy of local variables and parameters the code contains a loop

Question 9		Multiple Answer	(1 points)
	Question:	Which of the following are true of processes?
		each executes in its own isolated region of memory each may have one or several threads a thread may belong to several processes the cpu alternates execution between different processes they cannot be interrupted by hardware devices each has its own copy of the files it is working on

Question 10		Multiple Answer	(1 points)
	Question:	Which of the following are performed during a context switch, but not during a mode switch (e.g. a kernel call)?
		save context of the processor save the PSW and PC restore the PSW and PC update the process control blocks of the old and new current process move the old current process to the appropriate queue update memory management data structures restore the context of the processor

Question 11		Multiple Answer	(1 points)
	Question:	Which of the following can trigger execution of the Dispatcher (i.e., a process switch)?
		clock interrupt I/O interrupt memory fault system call trap process termination