[ The PC Guide | Systems and Components Reference Guide | Motherboard and System Devices | System Cache | "Layers" of Cache ]

Disk Cache

A disk cache is a portion of system memory used to cache reads and writes to the hard disk. In some ways this is the most important type of cache on the PC, because the greatest differential in speed between the layers mentioned here is between the system RAM and the hard disk. While the system RAM is slightly slower than the level 1 or level 2 cache, the hard disk is much slower than the system RAM.

Unlike the level 1 and level 2 cache memory, which are entirely devoted to caching, system RAM is used partially for caching but of course for other purposes as well. Disk caches are usually implemented using software (like DOS's SmartDrive). They are discussed in more detail in the section on hard disk performance.

Next: Peripheral Cache

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