olpcfs next steps (was very simple datastore reimplementation)
tomeu at tomeuvizoso.net
Fri May 9 06:09:49 EDT 2008
On 5/8/08, C. Scott Ananian <cscott at laptop.org> wrote:
> On Thu, May 8, 2008 at 3:11 PM, Marco Pesenti Gritti <mpgritti at gmail.com> wrote:
> > On Thu, May 8, 2008 at 8:43 PM, C. Scott Ananian <cscott at laptop.org> wrote:
> > > Again, in the olpcfs design we provide a vfat-like metadata structure
> > > (mounted via FUSE) so that the filesystem on the USB key appears to
> > > the journal code just like the flash does. No FUSE is necessary to
> > > see the files on the Windows box, although if you want to see all the
> > > metadata then you need some tool. If you're transferring the file to
> > > another XO, then the metadata comes along with you.
> > These are all very good points in favor of olpcfs to me.
> > Personally I'm pretty much sold on the design. And I'm all for
> > experimenting with it on a branch (try to port journal and a few
> > activities), even if it's not a priority for August. Are you aware of
> > any showstopper in this regard? Feature wise it seem to be pretty much
> > there already.
> The current implementation of indexes is incomplete, and there are
> some design questions regarding how search results for certain key
> types ought to be presented using the POSIX API. These are not
> showstoppers, but I/we should finish the implementation before Journal
> search would be expected to work.
Have you already thought about using something like Xapian for all the
search needs? Eben will correct me, but I think that we want pretty
advanced "Google like" search. Implementing all this on top of a
berkeley db may mean duplicating a lot of work.
I think that with a couple dozens of new lines of code, I can bring
the DS rewrite to the functionality of the old DS. That will appear
(hopefully soon) in:
> I also haven't implement version
> tagging or version gc, but these wouldn't be required to start playing
> with things.
> There are some journal integration questions, for
> example w.r.t. grouping objects by action -- if a number of files have
> 'action_id' set to (say) 1, is there a file named '1' with mime-type
> 'text/sugar-action' somewhere with more details about the action?
> That sort of thing is best figured out by actually hacking up some
> code and figuring out what extra information needs to be stored.
Yes, we have some unfortunate uncertainty there. But how this affect olpcfs?
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