I mentioned this before in the Lazy Reading from last Sunday, but it’s worth a second look: Apple’s new Fusion Drive product appears to be very much like DragonFly’s swapcache. DragonFly doesn’t have exclusive right to the idea of caching on a faster disk, clearly, so I’m not complaining that it’s “ours”. It’s frustrating to see product announcement/press releases stumbling all over this like it’s a new thing.
Then again, having new ideas about technology ideas and making sure they spread is one of the points of the BSD license, so perhaps there’s no good reason to complain at all.
(Before anyone reads too much into this: No, I don’t know of any direct relationship between swapcache and Fusion Drive; they may have no common background other than structure.)
Windows had http://en.wikipedia.org/wiki/ReadyBoost earlier than DragonFly had swapcache.
And I’m sure there’s people at Microsoft making the same face as me about it.
Except that it’s a tiered storage solution, not merely caching; not quite the same.
I’d say Solaris with ZFS was first to use SSDs as a cache. See http://dtrace.org/blogs/ahl/2008/07/01/hybrid-storage-pools-in-cacm/
»I wrote an article about the hybrid storage pool (HSP); that article appears in the recently released July [2008!!!] issue of Communications of the ACM. You can find it here. In the article, I talk about a novel way of augmenting the traditional storage stack with flash memory as a new level in the hierarchy between DRAM and disk«
So it looks like the answer is that OS X is the last to get this functionality, but the first where it’s noticed by the press.
Apple is a “mainstream” OS, that gets the benefit of modern, blazing-fast SSDs to make their implementation shine. ReadyBoost mostly used slower USB sticks (and Vista’s general perceived suckage made ReadyBoost look like turd wax anyway). While Dragonfly’s swapcache (and probably ZFS’ implementation) are technically adept, they are niche technologies in niche OSes (from the mainstream press’s point of view) that wouldn’t get much print no matter how good they were.