Välimuistista

Välimuisti, often referred to as cache in English, is a temporary storage area used to speed up data access. It holds frequently used data so that it can be retrieved more quickly than accessing the original source. This is particularly useful in computing, where accessing main memory or disk storage can be relatively slow compared to specialized cache memory.

There are various types of caches. Processor caches, also known as CPU caches, are located very close to the processor and store instructions and data that the CPU is likely to need soon. This significantly reduces the time the CPU spends waiting for information. Web browsers also use a cache to store copies of web pages, images, and other files that a user has previously visited. When a user revisits a page, the browser can load it much faster by retrieving the content from the local cache instead of downloading it again from the internet.

Similarly, operating systems and applications can employ caching mechanisms to improve performance. Disk caches, for instance, store recently accessed data from a hard drive or solid-state drive in RAM, making subsequent accesses to that data much quicker. The fundamental principle behind all forms of caching is to exploit the principle of locality, which states that programs tend to access data that is near data they have recently accessed or will access in the near future. By keeping this data readily available in a faster storage medium, overall system performance is enhanced.