ECE3055 Fall'99 Homework Assignment #2

Due before 3:00 p.m. Thursday 2/10/00

***START_HW*** (do not delete preceding flag, the ]-XXXX flags, the
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#1.  Enter the word in ()'s which is the best answer.
 
 In a memory hierarchy, the higher levels are (relative to lower) :

[ Closer ]  (Closer , farther) to/from the CPU.

[ Faster ]  (Faster, slower) access time.

[ More ]  (More, less) expensive.

[ smaller ]  (Larger, smaller) memory size.

#2. Answer T (true) or F (false).

[ T ]  The design goal is to have a memory nearly as fast as the
fastest level and as large as the cheapest level.

[ F ]  In a Direct Mapped Cached, the oldest block is replaced when a
new block is needed.

[ F ]  A "hit" means we have to read from a lower level.

[ T ] The Tag concatenated with the Index is the Word address.

[ F ] The Tag concatenated with the Index is the Byte address.

#3.  Enter the word in ()'s which is the best answer.

[ increases ]  Increasing the block width in a wide memory organization
(increases, decreases) the hit rate.
 
[ increases ]  Increasing the block width in a wide memory organization
(increases, decreases) the miss penalty (size constant).

[ sometimes ]  Increasing the block width in a wide memory organization
(always, sometimes, never) improves memory performance.

#4.  Having an n-way associative memory:

[ increases ]  Increasing n in a n-way associative memory organization
(increases, decreases) the hit rate.
 
[ * | neither ]  Increasing n in a n-way associative memory organization
(increases, decreases) the miss penalty.

[ sometimes ]  Increasing n in a n-way associative memory organization
(always, sometimes, never) improves memory performance.

#5.  Match answers to questions.

A. Dirty Bit
B. Valid Bit
C. Index
D. Tag
E. Byte Offset
F. Last Bit or Age Count

[ C ]  Part of the Block Address not used as Tag.
[ D ]  Part of the Block Address not used as Index.
[ E ]  Not used to address or flag data in the cache.
[ B ]  Flag that shows the Block has been written from lower level.
[ A ]  Flag that shows the Block has been just written by the CPU.
[ F ]  In an Associative memory, shows which element in a block is the
oldest. 

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