[WikiReader] file system questions (was: [wikireader]Suggestions for next steps on software)

Sean Moss-Pultz sean at openmoko.com
Sat Oct 31 02:35:42 CET 2009

On Sat, Oct 31, 2009 at 3:46 AM, Doug Jones <dj6mf at frombob.to> wrote:
> [snip]
>> I like this approach, just remind that as far I see the code and by
>> comments of the devs, the kernel implements the bare just enough to
>> read files, so I think directories are not implemented at all that's
>> why all is on root directory so at least basic hierarchical filesystem
>> has to be implemented before we can do this solution. But directories
>> will easy the organization of pictures too
> Good point.
> So two important questions to be answered, before we get any further
> into this:
> (1) Has OpenMoko made the policy decision that filenames will be limited
> to 8.3?

We're using FAT.

> (2) How complicated will it be to implement subdirectory support?

Not a problem. We're going to do something like this when we support
more languages.

> Note that only one subdirectory level is really needed to implement what
> has already been suggested.
> The current implementation contains 81 files, totaling 4.2GB for the
> English version.  Nearly all of that is in the big wiki data files
> (pedia*).  The other files, the ones you get when you make install,
> comprise 49 files and only 18MB, and most of that is fonts (which are
> often different for different languages).


> We could adopt a brain-swap approach:  After bootup, the user selects
> one wiki and then the app switches to the selected subdirectory and
> considers that to be the root until the next cold boot.  All 81 files
> for that particular wiki and language would be in that subdirectory,
> including the big wiki data files and the fonts and the remaining files
> (45 files, only 381KB, and this includes ALL of the executables!)  While
> the single app is running, it would not have to access (or even know
> about) anything outside its current directory, so no filesystem calls
> relating to directory navigation would be needed within that particular
> kernel.elf.  Only the initial wiki selection app (we would have to write
> one) would have to understand subdirectories, and only to one level deep.

Yeah that should work.


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