Caches are special storage devices that are extremely fast! They can be used to accelerate computer operations while still keeping computer prices low. The way caches work is that they use faster and smaller memories to make the slower and larger memories like RAMs and hard disks operate more quickly.
There are two levels of caches. The Level 1 cache is the smaller and faster of the two. It is as fast as the CPU, and sometimes, it is even built directly into the microprocessor! The Level 2 cache is slower and slightly bigger than the Level 1 cache, but it is still twice as fast as the RAM! These two caches are used to accelerate the RAM, and they are used to store the data most frequently accessed by the CPU.
However, even though there are two distinct levels of caches, other types of memories could be used for caching. For example, a RAM could be used to cache a hard disk, and a hard disk could be used to cache the Internet. This is how it would work:
When you access an Internet site for
the first time, the HTML site is downloaded and stored into the hard disk.
The next time you access this site, the computer checks to see if site has
been updated. If not, then it uses the version of the site on the hard disk
instead of having to download it again. This would be a cache because it makes
a slow process like the Internet much faster!
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