AtheOS File System
Encyclopedia
The AtheOS
file system
(AFS) was originally used in the AtheOS operating system
, and is now a part of the Syllable
operating system. AFS started with exactly the same data structure
s as the Be File System
, BFS, and extended its feature set in many ways. As such, AFS is a 64-bit journaled file system with support for file attributes. File indexing and soft deletions are also partially supported.
A few definitions:
AtheOS
AtheOS was a free and open source operating system for x86-based computers. It was initially intended as an AmigaOS clone, but that objective was later abandoned...
file system
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...
(AFS) was originally used in the AtheOS operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
, and is now a part of the Syllable
Syllable (operating system)
Syllable Desktop is a free and open source operating system for Pentium and compatible processors. Its purpose is to create an easy-to-use desktop operating system for the home and small office user...
operating system. AFS started with exactly the same data structure
Data structure
In computer science, a data structure is a particular way of storing and organizing data in a computer so that it can be used efficiently.Different kinds of data structures are suited to different kinds of applications, and some are highly specialized to specific tasks...
s as the Be File System
Be File System
The Be File System is the native file system for the BeOS....
, BFS, and extended its feature set in many ways. As such, AFS is a 64-bit journaled file system with support for file attributes. File indexing and soft deletions are also partially supported.
A few definitions:
- Journaled -- All file system transactions are first written to a journal before they are executed. When mounted, the file system replays everything in the journal. So, if something catastrophic occurs as data is being written to the file system, the file system can recover.
- File Attributes -- Name/value pairs tacked on to a file. For example, an audio file might have attributes for Artist, Title, and Album. This lets the file system search files in intelligent and flexible ways; example: search for all songs by Elton JohnElton JohnSir Elton Hercules John, CBE, Hon DMus is an English rock singer-songwriter, composer, pianist and occasional actor...
that exist on the drive. - File Indexing -- A persistent and up-to-date list of all files with a specific attribute, and the value of that attribute. So, the system may have an index for the Artist attribute on MP3 files. This speeds searching, but slows system performance when large numbers of files are created.
- Soft Deletions -- When the file system is told to delete a file, the file is actually hidden, and removed later by other means. In AFS, files are moved to an invisible directory and only deleted when the file system is next mounted.