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For developers
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The people behind SFS

There are some very good reasons to write a new filesystem for the Amiga.  Most of them are related to problems with the currently available filesystems but there is also much room for improvement.

The FastFileSystem (FFS)

This filesystem is used on almost all Amiga computers as it is built-in the AmigaOS.   It is a filesystem which has some very good things going for it.  FFS stores a lot of redundant information in such a way that even if a FFS disk is heavily damaged (partially formatted for example) that it is still possible to recover data from it with good results using a good recovery tool.

The problems of FFS

  • The 30 character limit on file and directory names.
  • If during write actions to the disk a crash or reset occurs your disk will need to be revalidated which can be a lengthy process.  There is also the remote chance that your disk will not validate at all because of somekind of error.  In that case you'll be forced to use a recovery tool to get your disk in working order again.
  • Performance with large files, for example 5 MB or more, isn't very good when you use the default blocksize of 512 bytes with FFS.  Larger blocksizes can fix this problem but introduce other problems.
  • Directory reading speed without the DirCache option is quite slow, and becomes even slower with larger blocksizes.
  • The DirCache option improves directory reading speed drastically.  However, using the DirCache option will cause an overall drop of performance.  Creating, deleting and renaming files will become slower.
  • Larger blocksizes can be used to improve a lot of performance problems in FFS, even to the point that the performance becomes quite acceptable (especially with the DirCache option).  Larger blocksizes however make FFS use a lot more diskspace than it does normally (especially if you have lots of small files).
  • The caching used in FFS is very simple and you'll need a lot of buffers to get good performance with large directories.
  • There are a lot of recovery tools for FFS available.  Most of them however only work with blocksizes of 512 bytes and do not support any of the 64-bit standards which allow for harddrives larger than 4 GB.  In other words, if you have a large harddrive or use large blocksizes you may be out of luck the next time your system recovers from a crash.
  • It doesn't seem likely there will be an update for FFS any time soon addressing these problems, as most of them will require major changes to the internals of FFS.

AmiFileSafe (AFS)

This is another filesystem which is still in use today.  It was originally named Professional FileSystem (PFS) and was written by Michiel Pelt.  I don't know the exact details but at some point in time Fourth Level Developments has acquired this filesystem and became its distributor.  Fourth Level Developments however didn't last very long and it seemed for a while that the development of AFS ended there.

Recently however, the original author of AFS, Michiel Pelt, has reacquired the rights to AFS and has made it available again under a new name:  Professional Filesystem 2.

This new version of this filesystem also seems to have solved most of its problems.   There seem to be recovery tools available and it's back under development again.

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For comments, problems or questions regarding this page contact John Hendrikx.
Last updated: 24 mei 1998.