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Amiga Fast File System

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This is an old revision of this page, as edited by Brynet (talk | contribs) at 18:23, 2 November 2007 (OpenBSD supports Berkely Fast File System and a FreeBSD update(FFS2), Amiga "FFS" is not the same as UFS.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

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.

History

FFS was introduced with version 1.3 of AmigaOS[1] in 1988[2].

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.

More recently, MorphOS and AmigaOS 4 have introduced support for a slightly updated Fast File System 2, or FFS2.

Like the normal (or "ancient") FastFileSystem, FFS2 is outdated compared to more modern file systems. It lacks the reliability and advanced features of more modern offerings. All FFS versions store 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 AmigaOS 4 and MorphOS. It implements long filename support while 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. It is still supported only for legacy purposes.

Characteristics

The Amiga Old File System article, in the section "Characteristics", presents the basic information regarding Amiga filesystems specifications.

References

  1. ^ http://www.gregdonner.org/workbench/wb_13.html
  2. ^ 1.3 release confirmed on September 16, 1888 by Carolyn Scheppner of CATS in amiga.dev in BIX. Copy of BIX announcement from USENET

See also

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