# HFS Plus

> file system developed by Apple

**Wikidata**: [Q1071337](https://www.wikidata.org/wiki/Q1071337)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/HFS_Plus)  
**Source**: https://4ort.xyz/entity/hfs-plus

## Summary
HFS Plus (also styled HFS+ and marketed as Mac OS Extended) is a file system developed by Apple Inc. and introduced on 1998-01-19 as the successor to the original Hierarchical File System (HFS). It has been used on macOS and is identified in registries such as PRONOM (fmt/1742); it was later replaced by Apple File System (APFS).

## Key Facts
- Developer: Apple Inc. (American multinational technology company based in Cupertino, California).  
- Inception / first published date: 1998-01-19.  
- Follows / predecessor: Hierarchical File System (HFS).  
- Replaced by: Apple File System (APFS).  
- Instance of: file system (concrete format for storing files and directories).  
- Common aliases: HFS+, Mac OS Extended, HFS Extended, Hierarchical File System Plus, Systeme de fichiers HFSX, Système de fichiers hfsx.  
- Operating systems that support or run it: macOS, Linux, Microsoft Windows.  
- PRONOM file format identifier: fmt/1742.  
- Common file extensions associated with HFS Plus disk images: .img, .dmg, .toast.  
- Partition type identifiers: Apple_HFS (Apple Partition Map), 0xAF (master boot record, hexadecimal), and GUID 48465300-0000-11AA- AA11-00306543ECAC (GUID Partition Table).

## FAQs
### Q: What is HFS Plus?
A: HFS Plus (HFS+) is a file system developed by Apple Inc. that succeeded the original Hierarchical File System. It was introduced on 1998-01-19 and has been used to store files and directories on Apple systems.

### Q: Which operating systems support HFS Plus?
A: HFS Plus is associated with macOS and is also supported by implementations on Linux and Microsoft Windows according to documented operating_system entries.

### Q: Is HFS Plus still the default Apple file system?
A: HFS Plus was replaced by Apple File System (APFS). The structured data lists APFS as the replacement for HFS Plus.

### Q: How is HFS Plus identified on disk and in registries?
A: HFS Plus is registered in PRONOM as fmt/1742 and uses partition type identifiers such as Apple_HFS (Apple Partition Map), 0xAF (MBR), and GUID 48465300-0000-11AA- AA11-00306543ECAC (GPT). Disk image extensions commonly associated are .img, .dmg, and .toast.

## Why It Matters
HFS Plus provided a standardized on-disk format for storing files and directories on Apple platforms for many years. As a successor to the original HFS, it served as the primary format associated with macOS environments and with tools that create or read Apple disk images (notably .img and .dmg files). Its registration in archival and technical registries (PRONOM fmt/1742) and the presence of defined partition type identifiers (Apple_HFS, MBR 0xAF, and a GUID for GPT) make it a recognized and interoperable format for cross-platform tools, data recovery, and digital preservation. The documented support on macOS, Linux, and Microsoft Windows reflects its practical role in enabling access to Apple-formatted volumes across multiple operating systems. Its eventual replacement by Apple File System (APFS) marks an architectural transition in Apple’s storage strategy, making HFS Plus an important predecessor for understanding Apple storage history, disk image ecosystems, and partition identification practices.

## Notable For
- Being the direct successor to the original Hierarchical File System (HFS) with a formal inception date of 1998-01-19.  
- Wide recognition in technical registries: PRONOM file format identifier fmt/1742.  
- Multiple disk image/file extensions associated with the format (.img, .dmg, .toast).  
- Explicit partition type identifiers across partition schemes: Apple_HFS (Apple Partition Map), 0xAF (MBR), and GUID 48465300-0000-11AA- AA11-00306543ECAC (GPT).  
- Known under several commercial and localized aliases (e.g., Mac OS Extended, Systeme de fichiers HFSX).

## Body

### Overview
- Name: HFS Plus (HFS+, Mac OS Extended, HFS Extended, Hierarchical File System Plus).  
- Type: File system (concrete format for storing files and directories).  
- Developer: Apple Inc.  
- Inception date: 1998-01-19.  
- Predecessor: Hierarchical File System (HFS).  
- Replacement: Apple File System (APFS).

### Technical identifiers & format registration
- PRONOM identifier: fmt/1742.  
- Freebase identifier: /m/03qrbq.  
- Common disk image/file extensions: .img, .dmg, .toast.  
- Partition type identifiers:
  - Apple_HFS (qualified by Apple Partition Map).  
  - 0xAF (hexadecimal, used in Master Boot Record).  
  - 48465300-0000-11AA- AA11-00306543ECAC (GUID Partition Table identifier).

### Platform support and compatibility
- Documented operating systems: macOS, Linux, Microsoft Windows.  
- The file system is associated with Apple’s operating system ecosystem and is listed as an instance of a file system in registries and documentation.

### Names, aliases, and localization
- Common aliases: Mac OS Extended; localized names include Systeme de fichiers HFSX and Système de fichiers hfsx.  
- Wikipedia title: HFS Plus.  
- Available Wikipedia language entries include: ca, cs, de, en, es, fr, it, ja, ko, nl.

### Documentation & references
- Described at: https://www.ntfs.com/hfs.htm and https://syntheway.com/Apple_HFS_Hierarchical_File_System_HFS_Plus_Mac_OS_X.htm (English descriptions).  
- Registry entry: PRONOM fmt/1742 (National Archives).  
- Gentoo wiki article: "HFS+" (English).  

### Metadata
- Instance count / sitelinks: sitelink_count recorded as 16.  
- Structured properties and identifiers are sourced from linked references to Apple Inc. and registries as documented.

## References

1. [Source](https://www.nationalarchives.gov.uk/PRONOM/fmt/1742)
2. Freebase Data Dumps. 2013