It was initially designed by French software developer Rémy Card as a replacement for the extended file system (ext).
Having been designed according to the same principles as the Berkeley Fast File System from BSD, it was the first commercial-grade filesystem for Linux.
Other implementations (of varying quality and completeness) exist in GNU Hurd,[8] MINIX 3,[9][10] some BSD kernels,[11][12][13] in MiNT,[14] Haiku[15] and as third-party Microsoft Windows[16] and macOS (via FUSE) drivers.
ext2 is still the filesystem of choice for flash-based storage media (such as SD cards and USB flash drives)[citation needed] because its lack of a journal increases performance and minimizes the number of writes, and flash devices can endure a limited number of write cycles.
[dubious – discuss] Since 2009,[18] the Linux kernel supports a journal-less mode of ext4 which provides benefits not found with ext2, such as larger file and volume sizes.
[19] The early development of the Linux kernel was made as a cross-development under the MINIX operating system.
[21] 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 gigabytes of data and filenames of up to 255 characters.
ext2 was also designed with extensibility in mind, with space left in many of its on-disk data structures for use by future versions.
On Linux kernels prior to 2.6.17,[22] restrictions in the block driver mean that ext2 filesystems have a maximum file size of 2 TiB.
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.
[23] Another good practice for filesystems on flash devices is the use of the noatime 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.
This is done to minimize the number of disk seeks when reading large amounts of contiguous data.
[26] The inode includes data about the size, permission, ownership, and location on disk of the file or directory.
The root directory is always stored in inode number two, so that the file system code can find it at mount time.
The only special treatment these two entries receive is that they are automatically created when any new directory is made, and they cannot be deleted.
It does not require user to make a new partition, and will continue to read or write existing ext2 file systems.
One can consider it as simply a way for the read and write routines to access files that could have been created by a simple utility similar to gzip or compress.
The latest patch for Linux 3.0 was released in August 2011 and provides multicore and High memory support.