The linux 2.6.27 kernel ([http://kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.27 full SCM git log]) is neither released nor finished. Its merge window has officially been closed by the [http://marc.info/?l=linux-kernel&m=121730204732684&w=2 2.6.27-rc1 release on July 28th 2008.]
Summary: 2.6.27 adds support for ...
1. Important features (the cool stuff)
1.1. UBIFS
UBIFS is a new filesystem designed to work with flash devices, developed by Nokia with help of the University of Szeged. It's important to understand that UBIFS is very different to any traditional filesystem: UBIFS does not work with block based devices, but pure flash based devices, handled by the MTD subsystem in Linux. Hence, UBIFS does not work with what many people considers flash devices like flash-based hard drives, SD cards, USB sticks, etc; because those devices use a block device emulation layer called FTL (Flash Translation Layer) that make they look like traditional block-based storage devices to the outside world. UBIFS instead is designed to work with flash devices that do not have a block device emulation layer and that are handled by the MTD subsystem and present themselves to userspace as MTD devices.
UBIFS works on top of UBI volumes. UBI is a LVM-like layer which was included in [http://kernelnewbies.org/Linux_2_6_22 Linux 2.6.22], which itself works on top of MTD devices. UBIFS offers various advantages to JFFS2: faster and scalable mount times (unlike JFFS2, UBIFS does not have to scan whole media when mounting), tolerance to unclean reboots (UBIFS is a journaling filesystem), write-back (which improves dramatically the performance), and support of on-the-flight compression.
Documentation: UBIFS [http://www.linux-mtd.infradead.org/faq/ubifs.html FAQ], more [http://www.linux-mtd.infradead.org/doc/ubifs.html documentation]
Code: [http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d (commit)], [http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0d7eff873caaeac84de01a1acdca983d2c7ba3fe (commit)], [http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e56a99d5a42dcb91e622ae7a0289d8fb2ddabffb (commit)]
2. Subsystems
3. Drivers
4. External Links
If you want to know what is waited before this kernelnewbies summary is completed, you can read
a review of what went into the merge window at the Linux Weather Forecast : [http://linux-foundation.org/weblogs/lwf/2008/07/29/the-2627-merge-window-closes/ The 2.6.27 merge window closes]
- feature lists on LWN
[http://lwn.net/Articles/289990/ 2.6.27: what's coming (part 1)]
[http://lwn.net/Articles/291033/ 2.6.27 merge window, part 2]
[http://lwn.net/Articles/291630/ 2.6.27 - the rest of the story]
* A wireless 2.6.27 feature-list at [http://wireless.kernel.org/News/kernel-2.6.27 Linux Wireless]