I was reading about disk cache. When i googled disk cache, the first result appears is
Blockquote A disk cache is a mechanism for improving the time it takes to read from or write to a hard disk. Today, the disk cache is usually included as part of the hard disk. A disk cache can also be a specified portion of random access memory (RAM). Blockquote
It is not very clear, where exactly the disk cache resides.
Can disk cache reside on hard disk too? If yes, how does it speed up the access times?
Can disk cache reside on both RAM & hard disk both?
Is it the same "cache" that "free" command prints? (for the portion of disk cache that resides on RAM)