Science  People  Locations  Timeline
Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Home > HFS Plus


HFS Plus or HFS+ is a file system developed by Apple Computer to replace their Hierarchical File System (HFS) as the primary file system used on Macintosh computers. It is also one of the formats used by the iPod hard-disk based music player. HFS Plus was introduced with the January 19 1998 release of Mac OS 8.1. HFS Plus is the name used by developers, but in user documentation the format is referred to as Mac OS Extended.

HFS Plus is an improved version of HFS, supporting much larger files (64 bit length instead of 32 bit) and using Unicode (instead of MacRoman) for naming the items (files, folders). HFS Plus permits filenames up to 255 characters in length, and n-forked files similar to NTFS, though access to forks other than the data fork and resource fork requires use of separate APIs, for backward compatibility with HFS. HFS Plus also uses a full 32-bit allocation mapping table, rather than HFS's 16 bits. This was a serious limitation of HFS, meaning that no disk could support more than 65,536 sectors under HFS. When disks were small, this was of little consequence, but as they started to approach the 1GB mark, it meant that the smallest amount of space that any file could occupy (a single sector) became excessively large, wasting significant amounts of disk space. For example, on a 1GB disk, the sector size under HFS is 16KB, so even a 1-byte file would take up 16K of disk space.

Like HFS, HFS Plus uses B-trees to store most volume metadata.

With the release of the 10.2.2Mac OS X version 10. 2 Jaguar is the third major release of Apple Computer's operating system Mac OS X after Mac OS X 10. 1 (Puma) and before Mac OS X 10. Features Increased support for Microsoft Windows networks Quartz Extreme for compositing graphics di update on November 11November 11 is the 315th day of the year (316th in leap years) in the Gregorian Calendar, with 50 days remaining. Events 1215 The fourth lateran council meets, adopting the doctrine of transubstantiation, meaning that bread and wine are transformed into t 20022002 is a common year starting on Tuesday (see link for calendar). 2002 was the first palindromic year since 1991 and the last until 2112. 2002 was also designated: International Year of Ecotourism and Mountains National Science Year in the United Kingdom, Apple added optional journaling features to HFS Plus for improved data reliability. These features were easily accessible in Mac OS XMac OS X is the latest version of the Mac OS operating system for Macintosh computers. Developed and published by Apple Computer, it provides the stability of a Unix operating environment and adds popular features of the traditional Macintosh user interfa Server, but only accessible through the command line in the standard desktop client. However, in 20032003 is a common year starting on Wednesday (link will take you to calendar), and also: The International Year of Freshwater The European Disability Year Summary Perhaps the defining global event of the year 2003 was the Invasion of Iraq launched by the U Mac OS X version 10.3 set all HFS Plus volumes on all Macs to be journaled by default.

External link

Computer file systems

Read more »

Non User