Ext2

ext2, or second extended file system, is a for the Linux kernel. It was initially designed by French software developer Rémy Card as a replacement for the (ext). Having been designed according to the same principles as the from BSD, it was the first commercial-grade filesystem for Linux. The canonical implementation of ext2 is the "ext2fs" filesystem driver in the Linux kernel. Other implementations (of varying quality and completeness) exist in GNU Hurd, MINIX 3, some BSD kernels, in MiNT, Haiku and as third-party Microsoft Windows and macOS drivers. ext2 was the default filesystem in several Linux distributions, including Debian and Red Hat Linux, until supplanted by ext3, which is almost completely compatible with ext2 and is a . ext2 is still the filesystem of choice for flash-based storage media (such as SD cards and USB flash drives) 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. Since 2009, the Linux kernel supports a journal-less mode of ext4 which provides benefits not found with ext2, such as larger file and volume sizes. The early development of the Linux kernel was made as a cross-development under the MINIX operating system. The was used as Linux's first file system. The Minix file system was mostly free of bugs, but used 16-bit offsets internally and thus had a maximum size limit of only 64 megabytes, and there was also a filename length limit of 14 characters. Because of these limitations, work began on a replacement native file system for Linux. To ease the addition of new file systems and provide a generic file API, , a virtual file system layer, was added to the Linux kernel. The extended file system (), was released in April 1992 as the first file system using the VFS API and was included in Linux version 0.96c. 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.