KernelNewbies:

Linux 2.6.30 is currently in development. The last prepatch version is -rc2, released the 15th April.

This page is, obviously, a work in progress.

Summary:

TableOfContents()

1. Prominent features (the cool stuff)

1.1. NILFS2, a log-structured filesystem

NILFS2 is a new filesystem, contributed by [http://en.wikipedia.org/wiki/Nippon_Telegraph_and_Telephone_Corporation NTT] (Nippon Telegraph and Telephone Corporation). It uses a [http://en.wikipedia.org/wiki/Log-structured_file_system log-structured] design. What makes log-structured filesystems different is that they treat the whole disk as a consecutive list of blocks (called log). All the operations append data at the end of the log, they never rewrite blocks (except when there's no space left - in that case, new blocks are reclaimed from the tail of the log). The advantage of this approach is that writes are always sequential. Crashes can't corrupt the filesystem. On mount, the filesystem detects the real end of the log, and continues working from that point.

Another advantage of this approach is that the log offers a coherent historical view of all the operations done in the disk in the past. This is called "continuous snapshotting" - snapshots of modifications done in all the filesystem at any time are created automatically due to the log-structure design, with no requeriment of intervention from an admin, and with the filesystem size as the only limit. NILFS2 allows to access those snapshots and even mount them (on read-only mode).

NILFS2 is [http://www.nilfs.org/en/current_status.html under development]. Code: [http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=tree;f=fs/nilfs2;hb=HEAD fs/nilfs2]. Filesystem web page: [http://www.nilfs.org www.nilfs.org]

1.2. Support for Object-Based Storage Device

Object-Based Storage Device (OSD) are basically "smart" disks, which do not store the data as blocks, but more elaborated objects. 2.6.30 adds support to these devices in the SCSI layer, as well as the addition of a filesystem (exofs, Extended Object File System) able to use them.

([http://lwn.net/Articles/305740/ LWN's Article], where exofs is still known by its old name, osdfs)

1.3. Local Filesystem Caching Infrastructure

FS-Cache is an infrastructure to locally cache remote (or slow) filesystems. It is described in more details in [http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/filesystems/caching/fscache.txt].

1.4. Filesystems performance improvement

Shortly after the 2.6.29 release, lots of discussions occurred on LKML about disk I/O (summary available [http://lwn.net/Articles/326471/ at LWN]), and how (and why) they can stall processes for minutes. Some measure have been taken to limit this, like setting the default mount-option to relatime, with 24 hours refresh time ([http://valhenson.livejournal.com/36519.html Detailed article in Valerie Aurora's blog]), and imporving fsync() for ext3.

1.5. Integrity Management Architecture

This is an infrastructure which use the Trusted Platform Module (TPM) to check that the OS has not been tampered with. ([LWN's article http://lwn.net/Articles/227937/]

2. Various core changes

3. Wi-Fi

4. Security

5. Networking

6. Tracing

7. Filesystems

8. Crypto

9. DM/MD

10. Virtualization

11. Architecture-specific changes

12. Drivers

12.1. Storage

12.2. Graphics

12.3. Network

12.4. Input

12.5. Sound

12.6. V4L/DVB

12.7. USB

12.8. HWMON

12.9. Watchdog

12.10. RTC

12.11. HID

12.12. MTD

12.13. MFD

12.14. Power

12.15. Serial

12.16. Various

13. Other sources about 2.6.30 kernel

KernelNewbies: Linux_2_6_30 (last edited 2009-04-19 19:11:00 by diegocalleja)