Re: Which fs is a good example for learning ?

["Francis Moreau" <francis.moro@gmail.com>]

On Tue, Jan 6, 2009 at 2:36 PM, Matthew Wilcox <matthew@wil.cx> wrote:
> On Tue, Jan 06, 2009 at 09:46:04AM +0100, Francis Moreau wrote:
>> That's what I think too but wasn't sure ext2 is still a good choice since it's
>> pretty old and it looks like some younger fs seems to make ext2 obsolete.
>> Also, it doesn't have a journal.
>
> This is all true.  It depends what your real goal is here.  If you want
> to learn the fundamentals of what a filesystem has to do to get blocks
> from disc and turn them into files, ext2 is perfect for your needs
> since it _doesn't_ have a journal or btrees or any of that fancy stuff.
> You can learn that later once you have the principles down.
>

If most of the fs use the same techniques as ext2 to get blocks from disk
then indeed ext2 is still a good candidate.

> If your goal is to learn how an advanced filesystem works, you might want
> to consider looking at JFS which has journals, extents, acls, xattrs and
> so on.  It's around 4x as big as ext2, but then it's also about 1/3 the
> size of XFS (just in terms of wc -l).  It's also been properly ported
> to Linux, unlike XFS which is still full of IRIXisms.

OK. I'll look at JFS if I'm still motivated after looking at ext2.

Thanks for the tips.
-- 
Francis