There is a great article at Computer World that talks about these hybrid drives as they are known.  If you are not aware of them, then here is a very quick rundown.

What are they:

• Traditional Hard Disk with larger cache (256MB-2GB)
• Uses Flash RAM instead of normal RAM

Why is this interesting:

• Cache size is much larger
• Cache is not lost when power is turned off
• Disk can stay spun down for longer as cache can manage read/writes, saving batteries and reducing heat
• Saves 90% of the power required to read from disk when using the Flash RAM
• Improves boot time as some boot code can be stored in FLASH - or pre-cached at shutdown or hybernation

There are two types of solution - one puts the cache physically on the drive and the other puts it on the motherboard, but the idea is the same.  Some people worry about the life of the flash as there will be considerable writing to it.  This is one of a couple of areas where Vista comes into the picture.  Vista can be aware of the cache, so will manage disk reads, writes, spin up & spin-down requests differently.  It can also help with the cache layout, ensuring spread usage of the cache to reduce the wear on the flash itself, this prolonging life.

If you want to know more about this, go have a look at the WinHEC presentation that is now available.

ttfn

David