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A memory store used to hold a copy of data, to improve the apparent speed of computer components including processors, disk drives, graphics cards etc. Where data is available in the cache it is retrieved from the cache instead of the device.

For example most processors contains a memory cache with faster access than main memory, data that is available in the cache is therefore available to the processor much faster than it would be if it had to go to main memory to retrieve the data. Information available in a disk cache can be returned almost instantly whilst data that is not available in the cache would need to be read from the physical disk and this would be magnitudes slower. cf buffer.

It is common for a cache to use a LRU algorithm to determine which item to remove from the cache when new data needs to be loaded into the cache. However there are other algorithms that some caches use, for example discarding the oldest item or an algorithm based on the frequency of use.

For more information see: