Amiga Fast File System
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The Amiga Fast File System (FFS) is a file system used on the Amiga personal computer. The Amiga Old File System (OFS) was too slow to keep up with hard drives. FFS differs mainly in the removal of redundant information. Data blocks contain nothing but data, allowing the filesystem to manage the transfer of large chunks of data directly from the host adapter to the final destination.
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[edit] History
FFS was introduced with version 1.3 of AmigaOS in 1988.
AmigaOS 3.0, designed for the Amiga 4000, introduced two new FFS modes:
- International mode allows FFS to handle filenames with international characters.
- Directory Cache mode allows the filesystem to access hard disks more rapidly by creating a cache of directory contents.
As any other directory caching based systems it used a certain amount of disk space to store the data.
Relatively recently MorphOS and the presently unreleased AmigaOS4 have introduced support for new FFS2 filesystem Or Fast File System 2.
Normal (or "ancient") FastFileSystem is outdated compared to more modern file systems; it lacks the reliability and advanced features of more modern offerings. FFS stores a "map" of the filesystem in a bitmap which is prone to deletion or corruption if the OS is reset or crashes during a write, resulting in data loss or invalidation of the filesystem.
FFS2 is a minor update of FastFileSystem for AmigaOS4 and MorphOS; it implements long filename support whilst maintaining backward compatibility with the older FastFileSystem and OldFileSystem. However its only major addition is the capability of handling longer filenames, and still suffers from the negative points of FFS, but is still maintained for legacy purposes.
[edit] Characteristics
The Amiga Old File System article, in the section "Characteristics", presents the basic information regarding Amiga filesystems specifications.
[edit] See also
[edit] External links
- The ADFlib Page and precisely ADF File specs
- The ADF specs, in LHA format from Aminet