[Uneex] dirpref and dirhash

[Kniazev, Sergei]

 Читал я тут новости про FreeBSD.
http://www.osnews.com/printer.php?news_id=153
<<<>>>>
Filesystem snapshot support (for UFS+Softupdates) is progressing nicely and
may prove to be one of the most important new filesystem features in the 5.x
system once it stabilizes. There are also two new native features in UFS
that have stabilized and have in fact been MFCd to -stable: dirpref and
dirhash. dirpref comes directly from Grigoriy Orlov of OpenBSD and reworks
the way directories are layed-out on disk, resulting in huge directory and
file stat/open/create/remove performance gains. Some filesystem operations
have improved by over 60x (6000%), and many of the common ones have improved
over 400%. dirhash is a very low-overhead in-kernel whole-directory hashing
mechanism that radically improves the performance of directory operations.
<<<<>>>>

Вопрос :кто-нибудь знает что такое dirpref и dirhash ?