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HFS Plus
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<p>HFS Plus or HFS+ (also known as Mac OS Extended or HFS Extended) is a <a href="/facts/Journaling_file_system/UCAaSBrD">journaling file system</a> developed by <a href="/facts/Apple_Inc./oTJYta3k">Apple Inc.</a> It replaced the <a href="/facts/Hierarchical_File_System_(Apple)/FVv6r1pe">Hierarchical File System</a> (HFS) as the primary file system of Apple computers with the 1998 release of <a href="/facts/Mac_OS_8/Vde5S5hl">Mac OS 8.1</a>. HFS+ continued as the primary <a href="/facts/Mac_OS_X/Y93vVpTm">Mac OS X</a> file system until it was itself replaced with the <a href="/facts/Apple_File_System/y16sIvSM">Apple File System</a> (APFS), released with <a href="/facts/MacOS_High_Sierra/RXfrv9pf">macOS High Sierra</a> in 2017. HFS+ is also one of the formats supported by the <a href="/facts/IPod/Uagdn1F6">iPod</a> digital music player. </p><p>Compared to its predecessor <a href="/facts/Hierarchical_File_System_(Apple)/FVv6r1pe">HFS</a>, also called <i>Mac OS Standard</i> or <i>HFS Standard,</i> HFS Plus supports much larger files (block addresses are 32-bit length instead of 16-bit) and using <a href="/facts/Unicode/DDu3MfPV">Unicode</a> (instead of <a href="/facts/Mac_OS_Roman/hzrt4zC5">Mac OS Roman</a> or any of several other character sets) for naming items. Like HFS, HFS Plus uses <a href="/facts/B-tree/IHE2l8GR">B-trees</a> to store most volume <a href="/facts/Metadata/qt35z79C">metadata</a>, but unlike most file systems that support <a href="/facts/Hard_link/Twqdfvlt">hard links</a>, HFS Plus supports hard links to directories. HFS Plus permits filenames up to 255 characters in length, and <a href="/facts/Fork_(file_system)/B1QFYk2t">n-forked files</a> similar to <a href="/facts/NTFS/dryNM3BK">NTFS</a>, though until 2005 almost no system software took advantage of forks other than the <a href="/facts/Resource_fork/zVnSVjbb">data fork</a> and <a href="/facts/Resource_fork/zVnSVjbb">resource fork</a>. HFS Plus also uses a full 32-bit allocation mapping table rather than HFS's 16 bits, improving the use of space on large disks. </p>