Gyorsítótár

Gyorsítótár, often translated as "accelerator cache" or simply "cache," is a term used in computing to describe a temporary storage area that holds frequently accessed data. The primary purpose of a gyorsítótár is to speed up data retrieval by making it readily available to a processor or application. Instead of having to access slower main memory or storage devices every time data is needed, the gyorsítótár provides a much faster pathway.

There are several types of gyorsítótár, each serving a specific purpose. CPU cache, for instance, is located directly on the processor chip and stores instructions and data that the CPU is likely to use soon. Disk cache, on the other hand, resides in RAM and stores data read from or written to hard drives or solid-state drives, reducing the need for physical disk access. Web browsers also employ a gyorsítótár to store website elements like images and HTML files, which speeds up page loading times on subsequent visits.

The effectiveness of a gyorsítótár relies on the principle of locality, which suggests that a program will tend to access data and instructions that are close to data and instructions it has recently accessed. When data is requested, the system first checks the gyorsítótár. If the data is found there (a "cache hit"), it is retrieved very quickly. If it is not found (a "cache miss"), the system must fetch the data from the slower main memory or storage, and a copy of this data is then placed in the gyorsítótár for future use. Managing the contents of the gyorsítótár, including deciding which data to keep and which to evict, is crucial for maintaining its performance benefits.