Editing B+ tree (section)

=== File systems ===

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 DO NOT add entries here which use regular B-tree indexes. Note that
 shady sources (blogs etc) are unreliable, as many confuse B-trees with B+ trees.
 For instance, MySQL, PostgreSQL and Firebird only support B-trees.
!!!!! -->
The [[ReiserFS]], [[Novell Storage Services|NSS]], [[XFS]], [[JFS (file system)|JFS]], [[ReFS]], and [[Be File System|BFS]] filesystems all use this type of tree for metadata indexing; BFS also uses B+ trees for storing directories. [[NTFS]] uses B+ trees for directory and security-related metadata indexing. EXT4 uses extent trees (a modified B+ tree data structure) for file extent indexing.<ref name="practical-book">{{cite book | last=Giampaolo | first=Dominic | year=1999 | url=http://www.nobius.org/~dbg/practical-file-system-design.pdf | title=Practical File System Design with the Be File System | publisher=Morgan Kaufmann | isbn=1-55860-497-9 | access-date=2014-07-29 | archive-url=https://web.archive.org/web/20170213221835/http://www.nobius.org/~dbg/practical-file-system-design.pdf | archive-date=2017-02-13 | url-status=dead }}</ref> [[APFS]] uses B+ trees to store mappings from filesystem object IDs to their locations on disk, and to store filesystem records (including directories), though these trees' leaf nodes lack sibling pointers.<ref>{{Cite book|url=https://developer.apple.com/support/downloads/Apple-File-System-Reference.pdf|title=Apple File System Reference|date=2020-06-22|publisher=Apple Inc.|page=122|chapter=B-Trees|access-date=2021-03-10}}</ref>