Section 12.8
Review Questions
Speeding up Virtual Memory
  1. What does the acronym TLB stand for?
answer...
Translation Lookaside Buffer
  1. What kind of a memory is the TLB?
answer...
associative
  1. Label the pieces of the hardware in the following picture: 
     MAR
     page table
     Virtual MAR
     TLB
answer...
  1. Explain why an associative memory is more like a human memory than is a conventional computer memory.
answer...
because items that you need to retrieve are found by their contents or part of their contents, rather than by a numerical address
  1. In the following picture that shows a mask register being used to help the MBR match the appropriate word in the associative memory, cross off the bits of the MBR that would change, and write out next to them what the new value would be.
answer...
  1. What is the main trade-off of associative memories? Why aren't they used more liberally in a computer?
answer...
they are much more expensive in terms of logic gates than ordinary memory
  1. What kind of slow algorithm is replaced by associative memory?
answer...
searching, especially sequential searching
  1. What hit ratio do virtual memory systems strive to attain in order to run most efficiently?
answer...
90%