Alexander Viro <viro@math.psu.edu> writes:
> The real problems with AFFS are different. I'll bring the pre-patch I've
> done back in September from backups tomorrow and then you'll get more
> detailed description, but right now I can recall the following:
> 1. AFFS handles links horribly.
> 3. Links on directories easily kill VFS. Don't.
> 4. Since some operations (e.g. rename) involve a _lot_ of hash
> chains walking and pointers switching - beware of the failure modes when
> you abort in the middle of modification. It may easily leave you with
> fucked up filesystem.
These problems you mention have been persisting in AmigaOS for years
ever since links had been introduced with AmigaOS 2, PLUS, AmigaOS shell
commands have had bugs so that only the GNU ported fileutils along with
the FileSystem-based (as opposed to dos.library based) ixemul.library
could get you rid of directory symlinks; this is partly because links
had originally not been present in AmigaOS 1.x, partly because they
fucked things up really bad.
> The bottom line: AFFS design is a festering pile of dung and attempts to
> make it look like UNIX filesystem only made it uglier. Judging by dejanews
> search, AmigaOS itself doesn't handle it well. Hell knows what had stopped
> them from replacing it with decent filesystem - with the thing outside of
> kernel it wasn't that hard to do... Damnit, FAT is not so braindead
> compared to that abortion.
There are some commercial (AFS/PFS - some versions of these are also
fucked beyond repair) and at least to freeware (SFS, Berkeley FFS Amiga
port) filesystems, I never checked them for completeness or stability,
though. Amiga users seem to be quite satisfied with SFS which is claimed
to be journalling.
The Dircache (DCFS) option of OFS/FFS (DOS\4 and DOS\5) are also claimed
to be fucked somewhat and slow things down for disks with low random
access times such as hard disks.
If you consider seriously revamping the AFFS support, I strongly urge to
get hold of Ralph Babel's "The Amiga Guru Book" which contains carefully
collected information on DOS internals, while you will still need the
Amiga Developer's CD for information on Dircache.
I've given up almost all my AmigaOS activities for the sake of Unix,
AmigaOS has given me too much grief with all its troubles, it had just
shoot one filesystem beyond recovery (into crash-on-access state) once
again.
And since that stuff is so severely fucked, I suggest marking write
support EXPERIMENTAL and add a kernel compile-time option for that.
-- Matthias AndreeWhere do you think you're going today?
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This archive was generated by hypermail 2b29 : Fri Mar 31 2000 - 21:00:28 EST