Hierarchical File System(HFS), can all refer to a tree-like stacking of files and directories or HFS, a file system utilized by Apple’s Mac OS.
In 1985, Apple introduced HFS, a file system for hard disk drives on Macintosh systems, which revolutionized storage technology. This succeeded MFS, which was released nearly two years prior with the first Mac computer. Apple’s remarkable hierarchical operating system SOS, which was utilized on their unsuccessful III model, was used to construct strong and efficient file structures that were also seen on IIe and Lisa machines.
While Apple’s Mac OS HFS and IBM HFS are no longer in use, the hierarchical file system notion remains since it is the only one that makes sense when storing data in logical blocks.
What is a File System?
A file system is a method of organizing and storing files on a computer in a systematic manner. It defines how data is stored on a disk and allows the operating system to access and alter files.
In practice, files may be sorted alphabetically, chronologically, or according to other criteria. Thousands of files are altered in computer systems as soon as the device turns on. A file system keeps track of when files are created, deleted, or modified.
What is Hierarchical File System?
To organize information, a hierarchical file system is utilized. A hierarchy is a folder structure that is structured from left to right. The folder, which is the system’s top level, is the root of the hierarchy. Each folder has its own sub-folder, separated by a forward or back slash. You’ll notice folders on the left and files on the right as you navigate the file path.
The Hierarchical File System (HFS) is a proprietary file system used by Mac OS X to store and arrange information on a computer. Apple engineers Patrick Dirks and Bill Bruffey created it.
HFS was first launched in 1985 with the initial Macintosh computer, which included a tiny hard disk drive, and has since seen various upgrades and improvements.
Features of Hierarchical File System
- It makes use of 512-byte blocks.
- Because HFS employs 16 bit, the maximum number of blocks is 65,535.
- Boot blocks are the first two blocks on the hard disk, 0 and 1. They have startup data in them.
- The Master Directory Block is located in Block 2. As implied by the name, it is a list of every file on the disk.
- HFS is a hierarchical file system, which means that files are organized in a tree-like structure with folders (also known as directories) and subfolders holding files and other folders. A Catalog File contains information about the tree structure.
Drawbacks of Hierarchical File System
- It can only support files up to 2 GB in size. This limits its use in modern computing.
- HFS can accommodate 54,536 separate files. This is a significant bottleneck.
- Mac OS 6 and 7 may run on 2 GB hard drives. This was increased to 4 GB in Mac OS 7.5. That is clearly insufficient.
- HFS is no longer used in the most recent versions of macOS. It was decommissioned in 1998. However, many older Macs may still use HFS, and HFS-formatted disks can still be accessed and used on newer Macs.
Hierarchical File System in Windows and Linux
A hierarchical file system is a way of storing and arranging files on a computer in the form of a tree, with a root directory at the top and subdirectories and files branching out from it.
Take note of the lowercase. It is the same as Mac OS’s namesake HFS file system.
Because you can go across the hierarchy to get the file you’re looking for, this structure provides a simple and structured approach to access and manage files.
All other directories and files on the computer are contained in the root directory, and each subdirectory can contain its own set of subdirectories and files. This allows for a flexible and scalable file organization.
Not only Mac OS, but also MS-DOS in the 1980s, featured a hierarchical file system.
These file systems are intended to be user-friendly and to provide a logical method of accessing and managing files on a computer.
Even Windows’ current NTFS file system employs a hierarchical file structure.
Example,
Your sales tax data for 2023 is in a hierarchical file system.
Your folder structure might look like this:
D (partition) – Business (folder) – 2023 (folder) – Tax (folder) – Sales Tax (folder) – Sales Tax Excel or PDF (file)
Other types of Linux hierarchical file systems include those used by network-attached storage devices and cloud storage services.
IBM Hierarchical File System
IBM’s HFS was based on the Portable Operating System Interface, or POSIX.
IBM HFS was released in the 1980s and was used on IBM’s OS/2 operating system (from which it was incorporated into early MS-DOS).
IBM HFS allowed for extended file names, file and folder permissions, and file sizes up to 2 GB. It was used by certain desktop computers in the 1980s and primarily by mainframe systems later.
It is vital to note that IBM’s HFS is not the same as Mac OS’s HFS (Hierarchical File System). The two file systems are fully distinct and incompatible with one another.
What is HFS+
HFS+ is a file system that Mac OS uses to store and organize files. It’s an improved version of the original HFS (Hierarchical File System) that debuted with the Macintosh in 1985.
HFS+ was introduced with Mac OS 8.1. It is a hierarchical file system as well.
HFS+ also has various improvements over HFS, including as support for larger volumes, faster file access, and enhanced error recovery. It is macOS’s default file system and is found on many older Macs. However, in the most recent version of macOS, it has been replaced by the newer APFS (Apple File System).
Features of HFS+
- It use 512-byte chunks.
- HFS’s gigabyte capacity has been replaced with terabyte capacity. Because of 32-bit computing, HFS+ can manage up to 8 exabytes.
- UTF-16 is used to encode files and folders.
- Long file names, Unicode characters, and file and folder permissions are all supported.
- The first two logical blocks are utilized to start the computer.
- The third, block 2, is utilized for Volume Header and performs the same function as the predecessor’s Master Directory Block.
- Uses an Allocation File to keep track of which blocks are empty.
- Stores tree structure information in a Catalog File.
Drawbacks of HFS+
- A significant bottleneck was revealed to be the Catalog File.
- By the year 2000, personal computing had advanced to the point that users could do more than just create papers and spreadsheets; they could also download music and use Yahoo Messenger to talk.
- The action was slowed down by the Catalog File, which could only be used by one process at once.
- The Apple File System, sometimes known as APFS, was created as a result.
Conclusion
The Hierarchical File System (HFS) is a good way to organize and manage files and folders. Its tree-like structure of directories, subdirectories, and files allows for a systematic approach to data storage and access. Users can quickly explore the directory structure and establish associations between files and folders with HFS. This technology has become a critical component of modern operating systems, allowing for efficient file management and easy data retrieval. Users can improve their file organization and overall computing experience by knowing the concept and benefits of the hierarchical file system.
