Reading Assignment and Discussion Topics
Computer Science 471

for class on Thursday Nov. 30, 2000

Please read sections 7.6 through 7.9 of the Patterson & Hennessy text (note Maurice Wilkes posing with a couple of kilobytes--that's kilobytes!--in the photo on page 622), and be prepared to discuss the following issue:

Consider the data reference of an unlucky (but legal) load instruction. How many bad things can happen to it? Missing in the cache is certainly one such thing, as is missing in the TLB. What about the memory reference made by the TLB miss routine to access the Page Table--can it too miss here and there? We will analyze a single load-word instruction whose data reference encounters every possible non-fatal problem the memory system can put in its way, and yet still manages to complete.

Please think about what all the problems might be and how each one is resolved. Write a list of the problems as part of your preparation.