HFS+

File Format
Name	HFS+
Ontology	Electronic File Formats Filesystem HFS+
PRONOM	fmt/1742
Released	1998

HFS+ (also known as Mac OS Extended) is an Apple MacOS filesystem that is the successor to HFS, with some improvements, such as using a 32-bit file length field rather than 16 to allow much bigger files. It also supports Unicode characters in file names, which can be up to 255 characters long and which can contain any characters in the Unicode repertoire, though there may be OS or API-specific restrictions on allowable characters.

Identification

For the original HFS+ format, the ASCII signature "H+" appears at offset 1024 of a raw image file.

For the HFSX extension of HFS+, the signature is "HX".

Format documentation

• Technical Note TN1150: HFS Plus Volume Format
• Technical Note TN1189: The Monster Disk Driver Technote

Software

• hfsxplorer (for Windows)
• HFS programs (for Linux)
• HFS Debugger
• 7-Zip

Sample files

• Norton AntiVirus 10 for Macintosh → "Norton AntiVirus 10.0 CD for Macintosh.toast" (APM with HFS+ partition)
• Rogue Ameoba Software (Macintosh) → "Rogue Ameoba Software (Macintosh).iso" (hybrid {APM with HFS+ partition} / ISO 9660)

Other links

• Wikipedia article
• Text encodings in VFS (Apple tech Q&A)
• HFS+ Bit Rot