what is cache memory

Cache Memory

One of the recommended ways to speed up CPU is to incorporate Cache memory. Cache memory is essentially a very high speed semiconductor memory and it acts as a buffer between the CPU and main memory. The most frequently used parts of data and program by CPU are held inside the cache memory. The operating system decides which parts of data and programs are to be transferred from disk to cache memory from where CPU can access them.

Features of Cache Memory:

Cache memory is faster than main memory.

It consumes less access time as compared to main memory.

It stores the program that can be executed within a short period of time.

It stores data for temporary use.

Cache memory has limited capacity.

It is very expensive.

How Cache Memory Works.

Caching strategies can be remarkably effective, no matter how simple it is. For example, the CPU fetches instructions continuously from memory and the next instruction usually resides in the address next to the current one. The simple caching strategy dictates that this memory location (and the following ones) are good candidates for caching. The same goes for holding data into the cache. Data from memory locations, who are neighbours to the location, from where data has recently been fetched, are good candidates for caching. By exploiting these techniques it is possible to achieve cache hit rates of well over 90%. Hit rates are calculated by measuring the percentage of data required by the CPU is found in the cache and a DRAM access is not required.

what is cache memory