[9fans] (no subject)

[9fans] (no subject)

[Steve Simon]

Hi,

Any advice on the "best" (I guess I mean simple and clean)
filesystem to look at as I try once again to teach
myself to write fileservers?

-Steve

Re: [9fans] (no subject)

[Wayne Walker]

If you plan on wirting a "unix-ish" file system, I think the SysV /
Coherent  fs was fairly simple (as simple as inode/superblock/indirect
block fs's go).  I've not looked at the actual linux or *BSD code for
that, though.

If you are looking for much simpler file system stuff, the romfs driver
in linux should be farily small and clean.

I cd'd into /usr/src/linux/fs and it looks like I'm right romfs and
ramfs are both tiny.  sysv and minix are the simplest "unixish" fs's (by
code size).

[wwalker@nomad fs]$ du -ks * | sort -n -r | grep -v '\.c$'
3220    nls
908     jfs
740     reiserfs
588     hfs
512     intermezzo
344     udf
340     jffs2
296     ntfs
268     ext3
264     nfs
220     partitions
216     jbd
212     nfsd
200     jffs
200     hpfs
184     smbfs
176     ufs
168     lockd
168     ext2
156     umsdos
156     ncpfs
152     befs
144     devfs
136     proc
128     coda
116     freevxfs
116     affs
108     fat
104     sysv
104     isofs
84      adfs
72      minix
68      autofs
64      autofs4
56      qnx4
44      vfat
44      efs
36      openpromfs
36      bfs
32      cramfs
28      msdos
24      romfs
24      devpts
16      ramfs
8       Config.in
8       ChangeLog
4       Makefile

On Mon, Feb 24, 2003 at 04:52:02PM +0000, Steve Simon wrote:
> Hi,
>
> Any advice on the "best" (I guess I mean simple and clean)
> filesystem to look at as I try once again to teach
> myself to write fileservers?
>
> -Steve

--

Wayne Walker

www.broadq.com :)  Bringing digital video and audio to the living room

Re: [9fans] (no subject)

[William Josephson]

On Mon, Feb 24, 2003 at 10:06:37AM -0600, Wayne Walker wrote:
> If you plan on wirting a "unix-ish" file system, I think the SysV /
> Coherent  fs was fairly simple (as simple as inode/superblock/indirect
> block fs's go).  I've not looked at the actual linux or *BSD code for
> that, though.

If you're actually looking for an on-disk filesystem,
kfs or FreeBSD's FFS are probably good places to start.
I have read-only FFS+buffer cache for plan 9 lying
around here somewhere which I suppose I should finish;
it already serves its purpose for doing physical backup
a la Russ's "trimfat" for FAT filesystems, though.

But I suspect you are looking for a Plan 9 filesystem, so
something like ramfs, webfs, or nntpfs might be better
places to start.  Lib9p is also worth poking at, IMO.

Re: [9fans] file systems

[Russ Cox]

the EXAMPLES section of 9p(2) gives some suggestions.

Re: [9fans] (no subject)

[northern snowfall]

RamFS is a nice clean and simple start.
Don

[9fans] file systems

[Joel Salomon]

> as simple as inode/superblock/indirect block fs's go
Speaking of which, how do I find out how the kfs is laid
out on disk?

--Joel

Re: [9fans] file systems

[Fco.J.Ballesteros]

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/sys/src/cmd/disk/kfs/portdat.h has the data structures.
Look for `don't touch, this is the disk structure' warnings.

You could also follow the trace resulting from a check call.

hth

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From: Joel Salomon <salomo3@cooper.edu>
To: 9fans@cse.psu.edu
Subject: [9fans] file systems
Date: Mon, 24 Feb 2003 14:29:16 -0500 (EST)
Message-ID: <Pine.SOL.3.96.1030224142637.17571B-100000@robin.cooper.edu>

> as simple as inode/superblock/indirect block fs's go
Speaking of which, how do I find out how the kfs is laid
out on disk?

--Joel

Re: [9fans] file systems

[Geoff Collyer]

`The Plan 9 File Server' (in /sys/doc/fs) describes how the pre-fossil
standalone file server stores data on disks.  kfs is a slight variant
of the non-cached-worm file system.  The main change I noticed when
adapting a private copy of kfs to read standalone file systems was
that struct Superb swaps the order of its members, a Super1 and an
Fbuf, to permit the size of the free list in Fbuf to vary with block
size, which can be chosen at run-time in kfs, but which is fixed at
compile-time in the standalone file server.