# Recent questions tagged cache-memory

1 vote
1
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? $8,5,3$ $8,6,2$ $7,5,4$ $7,6,3$
2
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
3
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
4
The principle of locality of reference justifies the use of Non reusable Cache memory Virtual memory None of the above
5
In a cache memory if total number of sets are ‘$s$’, then the set offset is: $2^8$ $\log_2s$ $s^2$ $s$
6
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
7
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.
8
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
9
Which of the following is an efficient method of cache updating? Snoopy writes Write through Write within Buffered write
10
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 $1.0.$
11
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?
12
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
13
Given the following information: TLB hit rate 95%, TLB access time is 1 cycle. cache hit rate 90 %, cache access time is 1 cycle. When TLB and cache both get miss; page fault rate is 1% The TLB access and acache access are sequential. ... 75 cycles Access to hard drive requires 50,000 cycles. Compute the average memory access latencies when the cache is physically addresses (in cycles).
14
Memory is word addressable with 16 bit addresses Word size=16 bits Each block is of size 16 bits. The cache contains 8 blocks. What is the address division for: 1>direct. 2>associative 3>set associative cache
15
A certain processor uses a fully associative cache of size $16$ kB, The cache block size is $16$ bytes. Assume that the main memory is byte addressable and uses a $32$-bit address. How many bits are required for the Tag and the Index fields respectively in the addresses generated by the processor? $24$ bits and $0$ bits $28$ bits and $4$ bits $24$ bits and $4$ bits $28$ bits and $0$ bits
16
A certain processor deploys a single-level cache. The cache block size is $8$ words and the word size is $4$ bytes. The memory system uses a $60$-MHz clock. To service a cache miss, the memory controller first takes $1$ cycle to accept the starting ... bandwidth for the memory system when the program running on the processor issues a series of read operations is ______$\times 10^6$ bytes/sec