Editing Ext2 (section)

==History==
The early development of the Linux kernel was made as a cross-development under the [[MINIX]] operating system. The [[MINIX file system]] was used as Linux's first file system. The Minix file system was mostly free of [[computer bug|bugs]], but used 16-bit offsets internally and thus had a maximum size limit of only 64 [[megabyte]]s, and there was also a filename length limit of 14 characters.{{r|Strobel}} Because of these limitations, work began on a replacement native file system for Linux.<ref name="Strobel">{{Cite book |last=Strobel |first=Stefan |title=Linux—Unleashing the Workstation in Your PC |last2=Uhl |first2=Thomas |publisher=Springer-Verlag |year=1994 |page=54}}</ref>

To ease the addition of new file systems and provide a generic file [[application programming interface|API]], [[Virtual file system|VFS]], a virtual file system layer, was added to the Linux kernel. The extended file system ([[Extended file system|ext]]), was released in April 1992 as the first file system using the VFS API and was included in Linux version 0.96c.<ref name="anatomyExt4">{{Cite web |last=Jones |first=M. Tim |date=17 February 2009 |title=Anatomy of ext4 |url=http://www.ibm.com/developerworks/linux/library/l-anatomy-ext4/ |archive-url=https://web.archive.org/web/20150220020146/http://www.ibm.com/developerworks/linux/library/l-anatomy-ext4/ |archive-date=2015-02-20 |access-date=8 February 2012 |publisher=IBM Developer Works}}</ref> The ext file system solved the two major problems in the Minix file system (maximum partition size and filename length limitation to 14 characters), and allowed 2 [[gigabyte]]s of data and filenames of up to 255 characters. But it still had problems: there was no support of separate [[time code|timestamp]]s for file access, [[inode]] modification, and data modification.

As a solution for these problems, two new filesystems were developed in January 1993 for Linux kernel 0.99: [[xiafs]] and the '''second extended file system''' ('''ext2'''),<ref name="anatomyExt4" /> which was an overhaul of the extended file system incorporating many ideas from the [[Berkeley Fast File System]].  ext2 was also designed with extensibility in mind, with space left in many of its on-disk data structures for use by future versions.{{citation needed|date=November 2022}} 

Since then, ext2 has been a testbed for many of the new extensions to the VFS API. Features such as the withdrawn [[POSIX]] [[access control list|draft ACL proposal]] and the withdrawn [[extended attribute]] proposal were generally implemented first on ext2 because it was relatively simple to extend and its internals were well understood.

On Linux kernels prior to 2.6.17,<ref>[https://archive.today/20120709233348/http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a0f62ac6362c168754cccb36f196b3dfbddc3bc3 linux/kernel/git/torvalds/linux-2.6.git/commitdiff:], [PATCH] 2TB files: add blkcnt_t,  Author:Takashi Sato, 26 Mar 2006 09:37:52 +0000 (01:37 -0800) — Commit allowing for large files, git.kernel.org</ref> restrictions in the block driver mean that ext2 filesystems have a maximum file size of 2&nbsp;TiB.

ext2 is still recommended over journaling file systems on bootable USB flash drives and other [[solid-state drive]]s{{by whom|date=February 2024}}. ext2 performs fewer writes than ext3 because there is no journaling. As the major aging factor of a flash chip is the number of erase cycles, and as erase cycles happen frequently on writes, decreasing writes increases the life span of the solid-state device.<ref>{{Cite web |title=Solid State Disk Drives |url=http://www.supertalent.com/tools/ssd.php |publisher=Super Talent Technology}}</ref> Another good practice for filesystems on flash devices is the use of the ''no[[atime (Unix)|atime]]'' mount option, for the same reason.

Beginning with Linux kernel 6.9, the ext2fs driver was deprecated and is no longer enabled in the default configuration. The central reason was that it did not support [[Y2038|dates past 2038]].<ref name="phoronix-deprecated">{{Cite web |last=Larabel |first=Michael |date=2024-03-26 |title=Linux 6.9 Deprecates The EXT2 File-System Driver |url=https://www.phoronix.com/news/Linux-6.9-Deprecates-EXT2 |access-date=2024-03-26 |website=Phoronix |language=en}}</ref> Users are recommended to upgrade to ext4.<ref name="bootlin">{{Cite web |last=Opdenacker |first=Michael |date=2024-03-25 |title=ext2 filesystem driver now marked as deprecated - Bootlin's blog |url=https://bootlin.com/blog/ext2-filesystem-driver-now-marked-as-deprecated/ |access-date=2024-03-26 |language=en-US}}</ref>