Editing HFS Plus (section)

== History ==
Codenamed ''Sequoia'' in development,<ref>{{cite web|author=Gregg Williams|date=May 19, 2000|title=Strategy Mosaic: Sequoia--Mass Storage for Tomorrow and Beyond|url=http://devworld.apple.com/mkt/informed/appledirections/sep97/stratmosaic.html|archive-url=https://web.archive.org/web/20000519230946/http://devworld.apple.com/mkt/informed/appledirections/sep97/stratmosaic.html|archive-date=May 19, 2000}}</ref> HFS+ was introduced with the January 19, 1998, release of [[Mac OS 8|Mac OS 8.1]].<ref name="tn1150">{{cite web | url=https://developer.apple.com/legacy/library/technotes/tn/tn1150.html | title=Technical Note TN1150: HFS Plus Volume Format | date=March 5, 2004 | work=Apple Developer Connection | access-date=2007-03-28 | archive-url=https://web.archive.org/web/20130622040013/https://developer.apple.com/legacy/library/technotes/tn/tn1150.html | archive-date=June 22, 2013 | url-status=live }}</ref>

With the release of the [[Mac OS X v10.2|Mac OS X 10.2.2]] update on November 11, 2002, Apple added optional [[Journaling file system|journaling]] features to HFS Plus for improved data reliability. These features were accessible through the GUI, using the [[Disk Utility]] application in Mac OS X Server, but only accessible through the command line in the standard desktop client.<ref>{{cite web | url=http://daringfireball.net/2002/11/crow | title=Crow | author=John Gruber | date=November 11, 2002 | work=DaringFireball.net | access-date=2007-03-28 | url-status=live | archive-url=https://web.archive.org/web/20070409153459/http://daringfireball.net/2002/11/crow | archive-date=April 9, 2007 }}</ref>

With Mac OS X v10.3, all HFS Plus volumes on all Macs were set to be journaled by default. Within the system, an HFS Plus volume with a journal is identified as ''HFSJ''.

Mac OS X 10.3 also introduced another version of HFS Plus called ''HFSX''. HFSX volumes are almost identical to HFS Plus volumes, except that they are never surrounded by the [[#Design|HFS Wrapper]] that is typical of HFS Plus volumes and they optionally support [[case sensitivity]] for file and folder names. HFSX volumes can be recognized by two entries in the Volume Header, a value of HX in the signature field and 5 in the version field.<ref name="tn1150" />

Mac OS X 10.3 also marked Apple's adoption of Unicode 3.2 decomposition, superseding the Unicode 2.1 decomposition used previously. This change caused problems for developers writing software for Mac OS X.<ref>{{cite web|url=http://kerneltrap.org/mailarchive/git/2008/1/23/593749/thread |title=Re: git on MacOSX and files with decomposed utf-8 file names |publisher=KernelTrap |date=2010-05-07 |access-date=2010-07-05 |url-status=dead |archive-url=https://web.archive.org/web/20110315014244/http://kerneltrap.org/mailarchive/git/2008/1/23/593749/thread |archive-date=March 15, 2011 }}</ref> 

Mac OS X 10.3 introduced a number of techniques that are intended to avoid fragmentating files in HFS+.<ref>{{cite web |title=Fragmentation in HFS Plus Volumes |url=https://osxbook.com/software/hfsdebug/fragmentation.html |website=osxbook.com |access-date=10 January 2020 |archive-url=https://web.archive.org/web/20200103202947/https://osxbook.com/software/hfsdebug/fragmentation.html |archive-date=January 3, 2020}}</ref>

With Mac OS X 10.4, Apple added support for Inline Attribute Data records, something that had been a part of the Mac OS X implementation of HFS Plus since at least [[Mac OS X v10.0|10.0]], but always marked as "reserved for future use".<ref>{{cite web | url=https://arstechnica.com/reviews/os/macosx-10.4.ars/6 | title=OS X 10.4 Tiger: Metadata revisited | author=John Siracusa | date=April 28, 2005 | work=Ars Technica | access-date=2007-03-28 | url-status=live | archive-url=https://web.archive.org/web/20070405040437/http://arstechnica.com/reviews/os/macosx-10.4.ars/6 | archive-date=April 5, 2007 }}</ref> Until the release of [[macOS Server|Mac OS X Server 10.4]], HFS Plus supported only the standard UNIX [[file system permissions]]; however, 10.4 introduced support for [[access control list]]–based file security, which provides a richer mechanism to define file permissions and is also designed to be fully compatible with the file permission models on other platforms such as [[Microsoft]] [[Windows XP]] and [[Windows Server 2003]].<ref>{{cite web | url=https://www.apple.com/br/server/macosx/windowsservices.html | title=Apple – OS X Server – Windows Services | work=Apple.com | access-date=2007-11-12 |archive-url = https://web.archive.org/web/20071231203318/http://www.apple.com/br/server/macosx/windowsservices.html <!-- Bot retrieved archive --> |archive-date = 2007-12-31}}</ref>

In Mac OS X Leopard 10.5, directory hard-linking was added as a fundamental part of Time Machine.

In Mac OS X Snow Leopard 10.6, HFS+ compression was added using Deflate (Zlib). In open source and some other areas this is referred to as AppleFSCompression or decmpfs. Compressed data may be stored in either an extended attribute or the resource fork. When using non-Apple APIs, AppleFSCompression is not always completely transparent.<ref>{{cite web|title=fileXray user guide and reference|url=https://filexray.com/fileXray.pdf|publisher=iohead LLC|access-date=14 July 2020|author=iohead LLC|page=31|year=2011}}</ref> OS X 10.9 introduced two new algorithms: LZVN (libFastCompression), and [[LZFSE]].

In Mac OS X Lion 10.7, logical volume encryption (known as [[FileVault|FileVault 2]]) was added to the operating system. This addition to the operating system in no way changed the logical structure of the file system. Apple's logical volume manager is known as Core Storage and its encryption at the volume level can apply to file systems other than HFS Plus. With appropriate hardware, both encryption and decryption should be transparent.