Re: Which fs is a good example for learning ?

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

On Tue, Jan 6, 2009 at 7:14 AM, Avishay Traeger <avishay@gmail.com> wrote:
> On Mon, Jan 5, 2009 at 10:59 PM, Matthew Wilcox <matthew@wil.cx> wrote:
>>
>> On Mon, Jan 05, 2009 at 09:40:50PM +0100, Francis Moreau wrote:
>> > I'd like to learn how file systems work on Linux and I don't know
>> > which file system driver I should look at to get a good picture of
>> > how a contemporary file system is designed.
>> >
>> > The choice has to be made according some criterias: the fs shouldn't
>> > be too hard since I'm pretty new in this area. Also not too
>> > old/obsolete since I'd like to learn from current technology.
>>
>> You're giving some contradictory criteria.  ext2 is probably the best
>> example to learn the basics, then you can move on to whichever
>> filesystem catches your fancy.
>
> This is all a matter of opinion obviously, but I would personally start with
> ramfs - it's only a couple hundred lines of code, and is very simple since
> everything resides only in memory.  This is useful for looking at the API
> and code flow.  Then you can go to a disk-based file system like ext2 which
> is a bit more complex but closer to what you're probably looking for.
>

ramfs seems a good example for learning the page cache. But since it's not
a disk based filesystem, it doesn't cover the block dev layer (bio, elevator...)
and more important all data structures used on the disk.

thanks
-- 
Francis