For each of the following statements, state if they are true or false. (a) A cac
ID: 2079757 • Letter: F
Question
For each of the following statements, state if they are true or false. (a) A cache using a write-back policy writes back to the main memory simultaneously as it writes to the cache. (b) Two important properties of a virtual memory are to give the illusion of a very large memory and to give memory protection between two concurrently running programs. (c) A unit called the memory management unit (MMU) is a common solution to perform fast translations from virtual page numbers to physical page numbers. (d) Modern high-performance processors do not use multi-level caches because they are too expensive and give little performance benefits.Explanation / Answer
a.)True
The advantage of write-back caches is that not all write operations need to access main memory, as with write-through caches.
— If a single address is frequently written to, then it doesn’t pay to keep writing that data through to main memory.
— If several bytes within the same cache block are modified, they will only force one memory write operation at write-back time.
b.)True
Provide at least two modes, indicating whether the running process is a user process or an operating system process.
c.)True.
d.)True.
Modern processors use high-performance cache replacement policies that outperform traditional alternatives like least recently used (LRU). Unfortunately, current cache models do not capture these high-performance policies as most use stack distances, which are inherently tied to LRU or its variants. Accurate predictions of cache performance enable many optimizations in multicore systems.