Basics of Caches:

"The caches are situated on basis of blocks, the shortest amount of data which may be copied between 2 adjacent levels at a time.

"If requested data by the processor is present in some the upper level block

 Then it is known as a hit.

"If data is not found in the upper level then this request is called a miss and the data is retrieved from the lower level in the hierarchy.

"The portion of memory accesses found in the upper level is known as a hit ratio.

"The storage, which takes profit of locality of accesses, is known as cache