SEMICONDUCTOR MEMORY DEVICES 12-17
However, at times, the data required by the processor is not available in cache, and then,
the speed factor is affected. However, this should occur only for a very small percentage
of accesses. That is how a figure close to the ideal can be aimed for. The achievement
of this goal depends on many factors: the architecture of the processor, the behavioral
properties of the programs being executed, and the size and organization of the cache.
Caches work on the basis of the principle of ‘locality of reference’ of program behav-
ior. This means that when the CPU accesses a memory location, all the information it needs
will be in sequential locations in and around this location. This is called ‘spatial locality’. ...