Why are RAM disks rarely needed?

A RAM disk is a virtual disk, created by software including a special driver, that uses the computer's RAM (Random Access Memory, main memory) to store its data.

Advantage

• Speed – a RAM disk is extremely fast.

Disadvantages

• Small size – a RAM disk is of limited size, because RAM is expensive.
• Memory reduction – a RAM disk steals memory from other uses and blocks it permanently, even when it is not being used.
• Volatility – a RAM disk loses all its contents when the operating system is shut down.

RAM disk software is readily and freely available (see http://www.google.com/search?q=ram-disk+windows).
However, few people actually use a RAM disk to their advantage. The main reason is that Windows already uses all unused RAM as a disk cache, so you already get RAM-disk-like access without doing anything.

By installing a RAM disk, you can easily get into a situation that is akin to stealing the diamonds from your wife (supposing you're male) and selling them back to her for a higher price. (It makes some business sense if your wife is independently rich, but not otherwise. :-)

That said, there are, of course, some situations in which a RAM disk is useful. These situations all have in common that you're using badly designed or obsolete software that does not use the available resources efficiently. This can sometimes be compensated by using a RAM disk. (Good software of course already uses RAM directly where it is better suited to the task, without having to resort to a RAM disk.)

Please add a comment if you find any errors or omissions or if you have any proposals for improvement.