# Recent questions tagged cache-memory

1
Consider a set-associative cache of size $\text{2KB (1KB} =2^{10}$ bytes$\text{)}$ with cache block size of $64$ bytes. Assume that the cache is byte-addressable and a $32$ -bit address is used for accessing the cache. If the width of the tag field is $22$ bits, the associativity of the cache is _________
1 vote
2
Assume a two-level inclusive cache hierarchy, $L1$ and $L2$, where $L2$ is the larger of the two. Consider the following statements. $S_1$: Read misses in a write through $L1$ cache do not result in writebacks of dirty lines to the $L2$ $S_2$: Write allocate policy must be ... $S_2$ is false $S_1$ is false and $S_2$ is true $S_1$ is true and $S_2$ is true $S_1$ is false and $S_2$ is false
3
Consider a computer system with a byte-addressable primary memory of size $2^{32}$ bytes. Assume the computer system has a direct-mapped cache of size $\text{32 KB}$ ($\text{1 KB}$ = $2^{10}$ bytes), and each cache block is of size $64$ bytes. The size of the tag field is __________ bits.
1 vote
4
Consider a machine with a byte addressable main memory of $2^{16}$ bytes block size of $8$ bytes. Assume that a direct mapped cache consisting of $32$ lines used with this machine. How many bits will be there in Tag, line and word field of format of main memory addresses? $8,5,3$ $8,6,2$ $7,5,4$ $7,6,3$
5
In time division switches if each memory access takes $100\;ns$ and one frame period is $125\;\mu s,$ then the maximum number of lines that can be supported is $625$ lines $1250$ lines $2300$ lines $318$ lines
1 vote
6
In a particular system it is observed that, the cache performance gets improved as a result of increasing the block size of the cache. The primary reason behind this is : Programs exhibits temporal locality Programs have small working set Read operation is frequently required rather than write operation Programs exhibits spatial locality
7
The principle of locality of reference justifies the use of Non reusable Cache memory Virtual memory None of the above
8
In a cache memory if total number of sets are ‘$s$’, then the set offset is: $2^8$ $\log_2s$ $s^2$ $s$
9
Which of the following is added to the page table in order to track whether a page of cache has been modified since it was read from the memory? Reference bit Dirty bit Tag bit Valid bit
10
A computer system with a word length of $32$ bits has a $16$ MB byte- addressable main memory and a $64$ KB, $4$-way set associative cache memory with a block size of $256$ bytes. Consider the following four physical addresses represented in hexadecimal notation. $A1= 0x42C8A4$ ... same cache set. $A3$ and $A4$ are mapped to the same cache set. $A1$ and $A3$ are mapped to the same cache set.
11
How many total bits are required for a direct-mapped cache with $128$ KB of data and $1$ word block size, assuming a $32$-bit address and $1$ word size of $4$ bytes? $2$ Mbits $1.7$ Mbits $2.5$ Mbits $1.5$ Mbits
12
Which of the following is an efficient method of cache updating? Snoopy writes Write through Write within Buffered write
13
The performance of a file system depends upon the cache hit rate (fraction of blocks found in the cache). If it takes $1\: msec$ to satisfy a request from the cache, but $40\: msec$ to satisfy a request if a disk read is needed, give a formula for the mean time required to satisfy a request if the hit rate is $h.$ Plot this function for values of $h$ varying from $0$ to $1.0.$
14
In the text it was stated that the model of Fig. $2-11(a)$ was not suited to a file server using a cache in memory. Why not? Could each process have its own cache?
15
To use cache memory, main memory is divided into cache lines, typically $32$ or $64$ bytes long. An entire cache line is cached at once. What is the advantage of caching an entire line instead of a single byte or word at a time?
1 vote