What is Cache memory?
CACHE Memory Cache memory is placed in between the CPU and the main memory. It is faster than the main memory. Hence access time is much less than that of the main memory. The access time of a cache memory is 15-25 nanoseconds (ns) whereas that of the main memory is 80 ns . One nanosecond =10 9 second. The cache memory stores the data and instructions which are to be immediately executed. It is used to reduce average access time for address, instructions or data which are normally stored on the main memory. Thus it increases the operating speed of the system. Cache memory is much costlier than the main memory. From economical considerations, the size of cache memory is usually smaller than that of the main memory. Sometime cache is used to store only instructions. One such type of cache is used in 68020 processor. It has 256 bytes instruction cache, which allows it to pre-fetch instructions from the main memory and store them in the cache during the period when the system bus ...