It turns out that caching is an important computer-science process that appears on every computer in a variety of forms. There are memory caches, hardware and software disk caches, page caches and more. Virtual memory is even a form of caching.

Caching is a technology based on the memory subsystem of your computer. The main purpose of a cache is to accelerate your computer while keeping the price of the computer low. Caching allows you to do your computer tasks more rapidly. Cache technology is the use of a faster but smaller memory type to accelerate a slower but larger memory type. A cache has some maximum size that is much smaller than the larger storage area. It is possible to have multiple layers of cache.

A computer is a machine in which we measure time in very small increments. When the microprocessor accesses the main memory (RAM), it does it in about 60 nanoseconds (60 billionths of a second). That's pretty fast, but it is much slower than the typical microprocessor. Microprocessors can have cycle times as short as 2 nanoseconds, so to a microprocessor 60 nanoseconds seems like an eternity.