Keep Hard Drive From Spinning Down

[rocketman221]

Is there any way to keep the hard drive from spinning down or changing the amount of time it waits to spin down?
When I am transferring files or downloading things from the web the hard drive will spin down while I'm downloading, then transfer will freeze while it immediately spins up again. It does this non stop every few seconds until the transfer finally finishes. This seems like a bug to me and it is making me crazy. I thought it was supposed to have a flash memory cache for this.