Editing File system (section)

====macOS====
[[macOS|macOS (formerly Mac OS X)]] uses the [[Apple File System]] (APFS), which in 2017 replaced a file system inherited from [[classic Mac OS]] called [[HFS Plus]] (HFS+). Apple also uses the term "Mac OS Extended" for HFS+.<ref>{{cite web|title=Mac OS X: About file system journaling|url=http://support.apple.com/kb/ht2355|publisher=Apple|access-date=8 February 2014}}</ref> HFS Plus is a [[metadata (computing)|metadata]]-rich and [[case preservation|case-preserving]] but (usually) [[case sensitivity|case-insensitive]] file system. Due to the Unix roots of macOS, Unix permissions were added to HFS Plus. Later versions of HFS Plus added journaling to prevent corruption of the file system structure and introduced a number of optimizations to the allocation algorithms in an attempt to defragment files automatically without requiring an external defragmenter.

File names can be up to 255 characters. HFS Plus uses [[Unicode]] to store file names. On macOS, the [[file format|filetype]] can come from the [[type code]], stored in file's metadata, or the [[filename extension]].

HFS Plus has three kinds of links: Unix-style [[hard link]]s, Unix-style [[symbolic link]]s, and [[alias (Mac OS)|aliases]]. Aliases are designed to maintain a link to their original file even if they are moved or renamed; they are not interpreted by the file system itself, but by the File Manager code in [[userland (computing)|userland]].

macOS 10.13 High Sierra, which was announced on June 5, 2017, at Apple's WWDC event, uses the [[Apple File System]] on [[solid-state drive]]s.

macOS also supported the [[Unix File System|UFS]] file system, derived from the [[BSD]] Unix Fast File System via [[NeXTSTEP]]. However, as of [[Mac OS X Leopard]], macOS could no longer be installed on a UFS volume, nor can a pre-Leopard system installed on a UFS volume be upgraded to Leopard.<ref>{{cite web|url=http://docs.info.apple.com/article.html?artnum=306516|title=Mac OS X 10.5 Leopard: Installing on a UFS-formatted volume|work=apple.com|date=19 October 2007|access-date=29 April 2016|archive-url=https://web.archive.org/web/20080316033439/http://docs.info.apple.com/article.html?artnum=306516|archive-date=16 March 2008|url-status=dead}}</ref> As of [[Mac OS X Lion]] UFS support was completely dropped.

Newer versions of macOS are capable of reading and writing to the legacy [[File Allocation Table|FAT]] file systems (16 and 32) common on Windows. They are also capable of ''reading'' the newer [[NTFS]] file systems for Windows. In order to ''write'' to NTFS file systems on macOS versions prior to [[Mac OS X Snow Leopard]] third-party software is necessary. Mac OS X 10.6 (Snow Leopard) and later allow writing to NTFS file systems, but only after a non-trivial system setting change (third-party software exists that automates this).<ref>{{cite web|last=OSXDaily|title=How to Enable NTFS Write Support in Mac OS X|url=http://osxdaily.com/2013/10/02/enable-ntfs-write-support-mac-os-x/|access-date=6 February 2014|date=2013-10-02}}</ref>

Finally, macOS supports reading and writing of the [[exFAT]] file system since Mac OS X Snow Leopard, starting from version 10.6.5.<ref name="encase-book">{{cite book|url=https://books.google.com/books?id=c1mezk6uHfIC&q=os+x+exfat+10.6.5&pg=PA79 |title=EnCase Computer Forensics - The Official EnCE: EnCase Certified Examiner |author=Steve Bunting |date=2012-08-14 |publisher=Wiley |access-date=2014-02-07|isbn=9781118219409 }}</ref>