Uncreative Labs

Posted: Sun Apr 20, 2008 2:33 am

Are there any hard disks out there that have a persistent cache? Rather than using RAM for a cache, the drive would use a flash or other type of memory chip that stores data when power's off. This would reduce the need for the drive to spin up to read and write recently accessed files. By keeping the hard disk off, much power could be saved which would mean better battery life.

I've been getting about an hour of battery life out of my laptop recently, as my workflow tends to involve saving *often*. I rarely write more than 80 characters before it's time to save. (I'm working on programming, sometimes it's just a matter of typing a line of code, compiling, and trying something else.)

I'm planning on using a thumb drive next time to see if I can get better battery life.

Joined: 19 Apr 2006 Posts: 261 Location: WisConSin

Quote:

Are there any hard disks out there that have a persistent cache? Rather than using RAM for a cache

No, but not a bad idea. There are of coarse reasons, flash ram actually cannot read/write as quickly as the drive can access data now that we are finally bumping the 166mhz transfer rate. (if it could be made to do so on both read and write it would be very expensive)

Also many drives actually use cache (aka srams) to cache which require very little logic, flash of coarse has overhead.

Patent and submit your idea to a company, to be honest a hybred drive sounds like an excellent niche product. Get about a 2gb-8gb cache size so that most everything you normally use is always on the cache so the drive almost never has to spin on. Then change the drive logic so the drive can access data while spinning up and increase the spin up time soo it requires less juice.

And yes a thumb drive if you can boot off it would definately save a LOT of battery life. If you had your bootables on a flash drive and other stuff on a non flash laptop drive that could be setup to shutoff quickly when not in use you could get away with something sort of like you describe without a special hd.

Good Luck