blah blah blah... snip snip snip... etc... etc... etc... The thing with Apple is that they are very good at spotting a niche market segment and making something happen. People LIKE solid state drives but for various reasons they want more capacity and production costs of high cap SSDs at this stage are still too expensive. Hybrid drives are good, people like them too, but they're still not SSD fast.
Apple brought to common market a standard, whatever that was we don't agree about, but that's kind of not the point. It was however that, that was already out there made user friendly with a buzz word "Fusion" because no else had just like the iMac, the iPod, the iPhone etc. If it succeeds we will see countless other "Fusion" drives out there if it fails to gain market traction like Thunderbolt then it will largely disappear from the mainstream market like the largely ignored niche market Firewire. I've already pointed to the biggest issue with logical volumes or whatever else you want to call them and it IS multiple points of failure, how Apple goes about protecting users against this is yet to be seen.
But the hair brained genius and probably the reason why no one else has done this is in the fact that it doesn't make sense in terms of data security and retention using traditional common sense when it comes to disk drives.
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This isn't a trick of formatting. The drive's format does not possess the needed abilities to carry out the process of determining and relocating recently used data.D.
All drives have this to some degree or another, it's what we call in layman terminology, a cache it just so happens that Seagate has a rather large one on their Momentus XT drives that does what Fusion does by moving commonly accessed files onto the "SSD"... What Apple has done here is most definitely not a party trick. Cache is what Fusion is more correctly, it's high speed fused memory to the circuit board of the hard drive for almost instantaneous access to recently used files. You are talking that which is almost as old as hard drives themselves technologically... In essence what apple has created is a large "cache" out of an SSD drive.