Hybrid iPods

I'm by no means the first to think of this idea, but the more and more I read about the hybrid hard drives, the more I think, hmm, could those work in an iPod? The idea is, you put the songs you think will be played in the flash and then you don't have to spin the hard drive. More on that in a sec.


For starters, this wouldn't work because the drives are physically too big. Right now, the drives I've read about only come in the 2.5 inch size, not the 1.8 size that the full size iPods use. It's only a matter of time before they get made in that size though, right?

Next, I wondered if the flash cache was big enough. Currently, they come with 512, or at most a gig. Is a gig enough? Ideally, you'd avoid the drive as much as you could and only play from the flash. If we assume a meg a minute, which is about right for 128 AACs or 192 MP3s, you'd get 1000 minutes or 16 and half hours of playback. That's more than a full run of the iPod's battery. This is starting to sound pretty good. If you could predictively populate the flash at sync time, when you have plenty of time and plenty of power, you skip the spinning drive and extend the battery life.

You'd get all of the benefits of a full iPod with the battery life of a nano. That would be cool.

So how would you fill the cache flash with the stuff you'd want, rather than the other 59 gigs of stuff you are carrying?
Well, iTunes could attempt some predictive algorithms to fill the flash, or perhaps they go the low tech route and just ask us. Just like the checkbox to "Play higher rated songs more often" in Party Shuffle, you could tick a box for flash-syncing the higher rated songs if you listen to those more often. Or, maybe you can designate a few playlists as flash-syncable because you know you listen to those the most. Combine that with smart playlists and you'd smart sync the right stuff a good portion of the time. I know I spend most of my time listening to a Not heard recently smart playlist that picks up any newly added content (including podcasts) along with the stuff I haven't listened to in months. This lets me get a nice mix of my new stuff while still keeping my whole library in rotation.

I wanted to see if you could do some predictive syncing and I also wanted to see how much music I listened to between syncs to see if this would work. I looked at my last 16 days of listening, which translates into 4-6 sessions. I'm defining a session as 3-4 days of playback. That's about how long a charge will last me and I need to do this because the last played times aren't the last synced times...unless you're using a shuffle which does set the last played at the time of sync.

I average about 3.5 hours of listening a day. Roll that up into a session and you have 10.5-14 hours which is less than the 16 hour figure from earlier. Still, that assumes a lot of positive hits coming out of the cache. Perhaps a 2 gig flash cache would work out better.

One last idea for those that like to shuffle. The set of tracks for the shuffle could be determined at sync time and populated in the flash. It would still be random, it just wouldn't be chosen at random at the time you were listening.