Extended file system

{{Use dmy dates|date=May 2023}}

{{short description|Linux file system}}

{{Expand language|topic=|langcode=de|otherarticle=extended filesystem|date=March 2023}}

{{Infobox file system

| name = ext

| full_name = extended file system

| developer = Rémy Card

| variants =

| introduction_date = {{Start date and age|1992|04|df=yes}}

| discontinuation_date = {{Start date and age|1997|01|14|df=yes}}
with Linux 2.1.21

| preceded_by = MINIX file system

| succeeded_by = ext2

| partition_id =

| directory_struct = Table

| file_struct = {{ubl

| Free space: Linked list{{Cite web |title=freelists.c - fs/ext/freelists.c - Linux source code (2.1.20)|url=https://elixir.bootlin.com/linux/2.1.20/source/fs/ext/freelists.c#L13 |access-date=2023-05-14 |website=Bootlin}}

| Metadata: Table

}}

| bad_blocks_struct = Table

| min_volume_size =

| max_volume_size = 2 GB

| max_file_size =

| max_files_no =

| max_filename_size = 255 characters{{Cite web|title=ext_fs.h - include/linux/ext_fs.h - Linux source code (0.96c-patch2)|url=https://elixir.bootlin.com/linux/0.96c-patch2/source/include/linux/ext_fs.h|access-date=14 May 2023|website=Bootlin}}

| max_dirname_size =

| max_directory_depth =

| dates_recorded =

| date_range =

| date_resolution =

| forks_streams =

| attributes =

| file_system_permissions = Unix permissions

| compression =

| encryption = No

| data_deduplication =

| OS =

| bootable =

| filename_character_set =

| file_types =

| introduction_os = Linux 0.96c

| file_size_granularity =

| copy_on_write = No

| website =

}}

The extended file system, or ext, was implemented in April 1992 as the first file system created specifically for the Linux kernel. Although ext is not a specific file system name, it has been succeeded by ext2, ext3, and ext4. It has metadata structure inspired by traditional Unix filesystem principles, and was designed by Rémy Card to overcome certain limitations of the MINIX file system.{{Cite web|url=http://www.april.org/groupes/entretiens/remy_card.html|title=Rémy Card (Interview, April 1998)|date=19 April 1999|publisher=April Association|access-date=8 February 2012|archive-url=https://web.archive.org/web/20120204082557/http://www.april.org/groupes/entretiens/remy_card.html|archive-date=4 February 2012|language=fr|url-status=dead}}{{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/ |url-status= |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}} It was the first implementation that used the virtual file system (VFS), for which support was added in the Linux kernel in version 0.96c, and it could handle file systems up to 2 gigabytes (GB) in size.

ext was the first in the series of extended file systems. In 1993, it was superseded by both ext2 and Xiafs, which competed for a time, but ext2 won because of its long-term viability: ext2 remedied issues with ext, such as the immutability of inodes and fragmentation.{{Cite web| url = http://e2fsprogs.sourceforge.net/ext2intro.html | title = Design and Implementation of the Second Extended Filesystem | first1 = Rémy | last1 = Card | first2 = Theodore | last2 = Ts'o | first3 = Stephen | last3 = Tweedie | access-date = 8 February 2012 | archive-url = https://web.archive.org/web/20120204044824/http://e2fsprogs.sourceforge.net/ext2intro.html | archive-date = 4 February 2012 | url-status = dead }} First published in {{Cite book | url = https://books.google.com/books?id=vRfKYgEACAAJ | title = First Dutch International Symposium on Linux | isbn = 90-367-0385-9 | publisher = State University of Groningen | year = 1995}}