ext2, who know the phrase, the second file system developed. the name of a file system for the Linux kernel, which is originally by Remy card as a replacement for a file system developed was designed. Implement conventional, the file system, etc. called ext2fs in the Linux kernel. The other implementation (that in the quality and integrity of differences) in GNU Hurd, etc. ^ " extension writing Part 3, Darwin, some of the cores, SMS, and Microsoft Windows is available. 2 in some Linux distros, such as Debian and Red Hat, as the File System Default was used before by the file system of the newer 3 was replaced. 3 almost completely with 2 is compatible and in addition to the capability of journaling, too, is equipped with that, debug and debug, it is more convenient. however, still 2 for the storage media based on Flash, such as SD card and USB flash drive is used, etc. Because the capability of journaling in such media enhances the performance, and not be on these media can only be a certain number of practice write did, and so the ability to use a journaling reduces the life of such media.