Can anyone explain what the DNS Cache is - or any cache for that matter!?

The DNS cache is a "store" of recently resolved URL to IP address combinations. It makes your future resolution much faster because it can be done localy on your PC rather than being done by a DNS server on the Internet.

Any, or most caches are to improve the performance of your computer. Temporary Internet files is one of the better known caches of files to improve Intertnet performance by retrieving a file localy insted of geting it from the Internet. Caching proxy servers use this to conserve bandwidth and increase the performance of an Internet connection.

Hope that helps.

Cache is something thats stored in memory/disk for faster access so visiting the web can be avoided (which takes time obviously - the roundtrip time).

DNS cache is something thats queried from the peer DNS servers if the record that was beeing looked up is not locally available. But, this will get cached once the information is queried.

DNS stands for Domain Name Server

This link might be able to explain it a bit better than I could.

Be prepared for some reading.

http://en.wikipedia.org/wiki/Cache

http://en.wikipedia.org/wiki/Dns