Editing JFS (file system) (section)

{{Short description|File system}}
{{Distinguish|text=the [[JFFS]] file system, [[Jews' Free School|JFS (School)]], or the [[Veritas File System]], which is called ''JFS'' on HP-UX}}
{{Use mdy dates|date=July 2017}}
{{lead rewrite|date=July 2014}}
{{Infobox file system
| name = ddhs
| full_name = IBM Journaled File System
| developer = [[IBM]] et al.
| introduction_os = JFS1 in [[IBM AIX|AIX]] 3.1 and JFS in [[OS/2]] 4.5
| introduction_date = 1990 and 1999
| partition_id = 0x35 ([[Master boot record|MBR]])
| file_struct = Bitmap/[[Extent (file systems)|extents]]
| bad_blocks_struct = 
| max_filename_size = 255 bytes
| max_files_no = No limit defined
| max_volume_size = {{nowrap|32 × 2<sup>50</sup> bytes}} (32 [[Pebibyte|PiB]])
| max_file_size = {{nowrap|4 × 2<sup>50</sup> bytes}} (4 PiB)
| filename_character_set = Any [[Unicode]] except [[Null character|NUL]]
| dates_recorded = Modification (mtime), attribute modification (ctime), access (atime)
| date_range = 
| date_resolution = 1&nbsp;ns
| forks_streams = Yes
| attributes = <!-- List of attributes that are supported for files and directories -->
| file_system_permissions = Unix permissions, [[Access control list|ACLs]]
| compression = Only in JFS1 on AIX
| directory_struct = [[B+ tree]]
| encryption = No (provided at the block device level)
| single_instance_storage = No
| OS = AIX, OS/2, [[Linux]], [[eComStation]], [[ArcaOS]]
}}

'''Journaled File System''' ('''JFS''') is a [[64-bit computing|64-bit]] [[journaling file system]] created by [[IBM]]. There are versions for [[IBM AIX|AIX]], [[OS/2]], [[eComStation]], [[ArcaOS]] and [[Linux]] [[operating system]]s. The latter is available as free software under the terms of the GNU General Public License (GPL). [[HP-UX]] has another, different filesystem named JFS that is actually an OEM version of [[Veritas Software]]'s [[VxFS]].

In the AIX operating system, two generations of JFS exist, which are called ''JFS'' (''JFS1'') and ''JFS2'' respectively.<ref name="faq">{{cite web |title=A Mini-FAQ for JFS |publisher=JFS for Linux project |url=http://jfs.sourceforge.net/project/pub/faq.txt}}</ref>

IBM's '''JFS''' was originally designed for [[32-bit computing|32-bit]] systems. '''JFS2''' was designed for [[64-bit computing|64-bit]] systems.<ref name="Journaled File System or JFS">{{cite web|title=IBM JFS and JFS2| publisher=IBM|url=https://www.ibm.com/docs/en/aix/7.3?topic=types-journaled-file-system-jfs}}</ref> 

In other operating systems, such as OS/2 and Linux, only the second generation exists and is called simply ''JFS''.<ref name="interview">{{cite web |title=Interview with the People Behind JFS, ReiserFS & XFS |url=http://www.osnews.com/story.php/69/Interview-With-the-People-Behind-JFS-ReiserFS-and-XFS}}</ref> This should not be confused with JFS in [[AIX operating system|AIX]] that actually refers to JFS1.