ZFS-loving Mac users demand support in OS X 10.9

HFS+ is the current file system used by OS X (and iOS). It was originally developed as HFS, or "Hierarchical File System," for the original Mac OS in the early '80s. A team at Apple, led by engineer Don Brady, adapted HFS for 32-bit systems in the mid-1990s. Brady later adapted HFS+ to work with the UNIX environment that OS X was built on, and over time he and other Apple engineers added additional features, including the extensible metadata used by Mac OS X's Spotlight search, live partition resizing used for Boot Camp, and the Adaptive Hot File Clustering used to reduce seek times for oft-used system files.

Despite all the features Apple has managed to tack on to HFS+, though, its design certainly isn't modern. "The initial HFS+ was primarily about addressing the block count problem," Brady told Ars in 2011. "Since we believed it was only a stop-gap solution, we just went from 16 to 32 bits. Had we known that it would still be in use 15 years later with multi-terabyte drives, we probably would have done more design changes!"