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Quiz 6 Key COP 5615 Fall 2011 1) a) What are the main differences between multiprocessor shared memory and DSM? (2 pts) b) What hardware supports exist for multiprocessor shared memory that do not for DSM? Why not? (2 pts) 2) a) Compare and contrast Barrier Synchronization with DSM weak consistency synch(). (4 pts) b) What are the differences between entry consistency and release consistency? (2 pts) KEY 1) a) The communication medium is very different; with MPSM we typically have a shared bus or a multistage interconnection network, while with DSM we have a LAN or a WAN. The transmission rates are much slower and the latencies much greater in the DSM case. Moreover, with DSM we must send complete messages, with MAC, Network, and Transport layer overheads. Overhead includes both space (headers/trailers) and processing at both ends, whereas in MPSM the requester simply asserts address, operation, and data (if write). b) MPSM often has a snooping cache, special hardware that monitors the shared
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This note was uploaded on 01/18/2012 for the course COP 5615 taught by Professor Staff during the Fall '08 term at University of Florida.
- Fall '08
- Operating Systems