I can't remember the last time I got tired from reading a review but reading this extraordinarily detailed review about Tiger, the latest version of OS X being released today, did. It started off fluffy enough but went on and on, diving into the guts about details only developers would care about. Being a developer, I enjoyed every page after page.
I did cringe though when I got to the page about the extended file attributes (aka file metadata) support because it mentioned HFS+. You see, I have painful memories of implementing HFS on top of *shudder* DOS for a client long time ago (can anyone member Dayna Communications?) during my Macintosh days. Files under HFS had two parts, data fork and resource fork. DOS files don't have resource fork which means, to allow Mac users to drag and drop Mac files into DOS diskettes, I had to come up with elaborate schemes to simulate it. The product got rave reviews but I regretted having taken on the contract afterward because the experience was definitely not fun.
Anyway, Apple apparently did the same in OS X to support non-HFS volumes by saving the resource fork under files with '._' prefix. Same file is used to store extended file attributes in non-HFS+ format volumes.
I am not sure if non developers will survive through the middle part of the long review, but I definitely recommended it for developers. Having read it, I pity the pre-Tiger OS X developers. They must have felt like eskimos living on drifting icebergs. Tiger seems like solid ground, however.