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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: trekiej on September 23, 2021, 03:43:49 AM
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I need an introduction to Amiga File System.
I have two Amiga A600's.
One has an SD Card and the other has a CF Card as a Hard Drive.
What File System would make them run the fastest?
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The only real options these days are FFS (default), SFS, and PFS.
FFS is the slowest. I don't know how SFS and PFS compare to each other in terms of speed, but I'm sure others can answer that.
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PFS is by far the fastest, especially on low-end machines.
Installation instructions and utilities: http://aminet.net/package/disk/misc/PFS3_53
Latest version (binary only): http://aminet.net/package/disk/misc/pfs3aio
SFS is a bit faster than FFS but slower than PFS. It needs a 68020 CPU. And it is a catastrophy regarding support. It can run stable over years, but if something goes wrong you usually lose everything. There is no repair tool and the only salvage tool does not work.
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I use PFS and get about 3.2 megabytes/sec on an HD connected to the standard IDE port.
I can back up my HD to an SD card in about 50 mins when the same capacity under FFS would be left to run overnight.
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What does OS 3.2 use natively?
I had three partitions and used System: for the installation.
It had OS 3.1 on it and OS 2.1 before that.
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The 3.2 feature set on the Hyperion website describes improvements to FFS to make it faster, so that seems to be the default file system.
However, if you did an upgrade or similar on an existing disk without using HDToolbox to change the filesystem in place, then your 3.2 installation will have just used whatever FS was on the drive.
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What does OS 3.2 use natively?
It uses the default file system ;)
The Amiga operating system has a designated "default file system" which is baked into the ROM. You can set up your hard disk/SSD/USB stick partitions to each use a different, specific file system such as PFS3 or SFS, but in the absence of you doing so, the responsibility for managing disk storage space will fall to the default file system.
If you list all the components by name which make up the Kickstart ROM contents you will find the default file system under "filesystem". This is the component which knows how to mount, read and write disks and partitions formatted using the FFS, DCFS, LNFS, etc. variations. A version of that "filesystem" component can be found on the installation disk under "L:FastFileSystem". It's basically the same thing as the "filesystem" in ROM, but can be used by HDToolbox to make partitions use that specific file system version.
What makes the default file system peculiar is that it has to support the complete documented feature set of what an Amiga file system could possibly do. This includes, for example, support for hard and soft links, file record locking, file/directory notification and even legacy API/data structure quirks which result from how dos.library expects the default file system to behave when the system starts up. This is why you cannot generally replace the default file system with a different one if you wanted to. The replacement would have to fill its shoes, which is a tall order (tall shoes, if you will).
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SFS is a bit faster than FFS but slower than PFS. It needs a 68020 CPU. And it is a catastrophy regarding support. It can run stable over years, but if something goes wrong you usually lose everything. There is no repair tool and the only salvage tool does not work.
I can speak to this exact scenario. MorphOS uses SFS by default and even there the situation there is not much better, despite being actively maintained, unlike the 68K SFS. I ran the MorphOS SFS repair/salvage tool to fix a directory block problem; it failed and destroyed the entire partition. Fortunately I had just done a full backup before tinkering. Good thing!
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Thanks a lot, I will have to check it out.
I am thinking of re-installing 3.1 on my other machine.
OS 3.2 pulls a Guru Meditation due to lack of ram.
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I tried using a PFS partition just for quicker loading times a few years back but after 6 months or so I started to get errors and then realized, as Thomas noted above, there was no repair etc program for it so I backed up the info I needed and went back to FFS…may be slower but I can tell you with confidence I’ve saved quite a few partitions over the years with various recovery programs from OS1.3 on
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Thomas described problems with SFS, not PFS. Which did you have problems with?
My HDD started to fail with a physical issue last year. I was able to use the PFS recovery tools to recover it long enough to back it up.