What's New in IT? - The GIGGAS's Blog

The GIGGAS's Blog

What's New in IT?

Posted on January 29, 2009 at 02:03 AM.

This was an assignment I had to finish for Software Engineering. I found it an interesting topic, so I'm going to repost it here.

ext4 is the new file system used by Linux. The development effort started on June 28th, 2006, when Theodore Ts'o announced the plan for development. ext4 was marked as stable on October 11th, 2008, which ended the development phase and moved into the maintenance phase. Finally, the first Linux kernel to contain the file system was released on December 25th, 2008.

1. Key Objectives
ext4 started as a series of improvements to the ext3 file systems, including performance enhancements and the addition of 64-bit storage limits. The ext line of file systems are extended file systems mostly associated with the Linux kernel and its many derivative distributions. According to Card, Ts'o, and Tweedie, the main architects of ext2, the �Second Extended File System (ext2) is probably the most widely used filesystem in the Linux community� (1). The improvements that ext3 made to ext2 will be dwarfed by those made by ext4, as ext3 only added journaling in order to increase speed. ext4 increases system/file sizes, along with other major improvements.

2. Difference From Existing Development Efforts
ext4's development effort was different than most due to the simple fact that it is open-source. That means that it is free to access and modify the source code, as long as you upload your changes back into the code tree. Also, this introduced more changes into the line of ext file systems than were incorporated into ext3.

3. Related Costs
As the development effort is a community-based open-source one, the only costs associated with the effort were of development hours. There are no given statistics on how many volunteers gave of their time to code nor of the time they spent developing the new file system. However, it is assured that many talented developers spent thousands of hours working on the ext4 file system during the 2+ years that it was in active development.

4. Consumers Reactions
Based on reactions from the official forums of the Linux distribution, Ubuntu, some users seem to be apprehensive about the prospective speed increases that ext4 is promising. A user named Cypher states: �For an average user of Ubuntu upgrading from EXT3 to EXT4 will yield no real benefit and is probably not really worth the hassle..�, while a user named Frak gives another viewpoint: �...There would probably be no improvement using EXT4. The bottleneck on regular HDDs prevents EXT4 from showing much improvement. You would need to have an SSD [solid state drive] to do anything much noticeable.� However, other users seem to be excited for ext4's speed, such as odinfromvalhalla: �Not sure about if it's ext4's fault but with Jaunty my notebook runs way better than before. I get to book login screen in ~18s (CPU T7500 @2.2Ghz and 4Gb Corsair).� Therefore, the reactions thus far have been varied. It is important to note that even though ext4 is finished with the major development effort, the file system will not be included by default in Ubuntu until the release of Ubuntu 9.04, scheduled for April 2009.

5. Future
ext4's future is bright, as it has not been included into the Linux kernel until recently. As more distributions include ext4 as the default file system, more and more users will be acquainted with it, and that will bring popularity and maintenance requests, which will increase the quality of the system.

References:

1. http://e2fsprogs.sourceforge.net/ext2intro.html
2. http://www.ibm.com/developerworks/linux/library/l-ext4/index.html
3. http://www.redhat.com/support/wpapers/redhat/ext3/#advantages
4. http://kernelnewbies.org/Ext4
5. http://ubuntuforums.org/showthread.php?t=1040332&highlight=ext4&page=2
6. http://ubuntuforums.org/showthread.php?t=1044487&highlight=ext4