HFStiedostojärjestelmästä

HFStiedostojärjestelmästä, often referred to as HFS or HFS+, is a hierarchical file system developed by Apple Inc. It was originally introduced with Mac OS 8.1 in 1998 and served as the primary file system for macOS until the introduction of APFS. HFS+ was designed to overcome some of the limitations of its predecessor, Hierarchical File System (HFS), offering improved performance and support for larger storage devices.

Key features of HFS+ include its ability to store file metadata, such as creation dates and author information, alongside the file data. It also supports resource forks, a mechanism that allowed applications to store additional data separate from the main file content, a concept particularly prevalent in older Mac applications. HFS+ uses a catalog B-tree to manage directories and files, allowing for efficient searching and organization. It also employs a volume allocation B-tree to track free and used space on the disk.

While HFS+ was a robust file system for many years, its limitations became apparent with the advent of modern storage technologies like SSDs and the increasing demands of mobile computing. Issues included fragmentation, slower performance on SSDs compared to newer file systems, and a lack of advanced features such as snapshots and space sharing across multiple volumes. These factors led to the development and eventual adoption of Apple File System (APFS) as the successor to HFS+. Despite its deprecation for newer systems, HFS+ is still compatible with recent macOS versions, allowing users to access older drives formatted with it.