Professional File System: Difference between revisions

Revision as of 10:46, 2 October 2015

Revision as of 12:57, 3 October 2015

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The '''Professional File System''' is a [[filesystem]] originally developed commercially for the [[Amiga]], it is now distributed on [[Aminet]] with a 4-clause [[BSD license]]. CompatibleIt is a compatible successor of ''Ami-FileSafe'AmiFileSafe''' (AFS), with an emphasis on added reliability and speed compared to standard Amiga filesystems.<ref name="EAL">{{cite journal|last=Favini|first=Andrea|title=Professional File System 3|url=http://www.webcitation.org/6c0Fpf268|journal=Enigma Amiga Life|___location=Italy|issue=122|access-date=3 October 2015}}</ref> It also features multi-user abilities like the older [[MuFS]].<ref name="EAL" />

The device is split into two main areas. At the beginning of the device is the metadata section, which consists of a root block, and a generic array of blocks that can be allocated to store metadata. The rest of the device is another contiguous generic array of blocks that can be allocated to store data. The metadata section usually uses a few percent of the device, depending on the size of the device.

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When a metadata update occurs, the system looks at the block containing the metadata to be changed, and copies it to a newly allocated block from the metadata section, with the change made, then it recursively changes the metadata in the block that points to that block in the same way. This way, eventually the root block needs to be changed, which causes the atomic metadata update.

The filesystem is reasonably good at keeping files unfragmented, although there is a defragmentation tool available which will work on an online{{cn}} filesystem.<ref name="EAL" />

It was the first{{cn}} filesystem to introduce the concept of the [[Recycle bin (computing)|Recycle Bin]] natively at filesystem-level to the Amiga, holding the last few deleted files in a hidden directory on the disk root.<ref name="EAL" />

PFS version 5.3 was developed in C and a small portion of assembly code by Michiel Pelt.

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* [[File system]]

* [[List of file systems]]

==References==

{{reflist}}

==External links==