[Sugar-devel] [Dextrose] Some quick comments on the Journal in 11.2.0 build 16 and Dextrose 508

[Bernie Innocenti]

On Sat, 2011-04-30 at 17:55 -0500, James Simmons wrote:
> On an XO-1 you probably could not copy a 700 MB video to the Journal
> at all.  My experience with CBZ files (Comic Book page images in a Zip
> file), which are generally 60 MB or so, made me question the wisdom of
> having such large files in the Journal.  As a result, I made a second
> comic book reading Activity called Read SD Comics, which is designed
> to store the CBZ's on an SD card.  The Journal entry is merely a
> pointer to the file on the SD card, and contains metadata like last
> page read, etc.  This is a big improvement, in my opinion.  You can
> get a 8 Gig Micro SD card with an SD adapter for about twenty bucks.
> This works perfectly with an XO-1, except that Activities in general
> don't use the SD card for anything.  The Read SD Comics approach could
> be ideal for files that are much too large for the Journal itself,
> like 700 MB movies.
> 
> You may also be familiar with my Sugar Commander Activity, which is a
> limited function Journal Activity alternative.  It is limited in
> function because only the original Journal Activity can do things like
> copy files to removable drives.  If it was possible to use my Activity
> in place of the original Journal Activity I could make it do much
> more.  If we had a generalized method of doing this we could have
> several possible Journal alternatives.  A child might start with the
> basic one and change to something else when he got older, for
> instance.  I remember in Windows 3.1 you could specify what executable
> you wanted to run as the Program Manager or File Manager.  This let
> you customize the OS in interesting ways.  The nice thing about having
> a pluggable Journal Activity is that instead of patching the existing
> Activity and getting a consensus that your patch is worthwhile you
> could create something radically different and throw it out to succeed
> or die on its own merits.

The Journal was indeed an activity initially. It was integrated into the
shell some time later, to solve some UI issues I can't remember. Perhaps
Marco could tell us more.

If it's feasible, I'd be in favor of letting kids experiment with
various journal implementations. In Android, even the Home application
is replaceable by users and I think we could do the same in Sugar.

Shredding Sugar into multiple application has a downside: each process
needs to import all the Python modules again, which results in higher
memory usage and slower startup. My last calculations on the XO-1 were
in the order of 2-3 seconds and 40-60 MB per process. The worse
offenders were PyGTK and NumPy. The latter has already been removed from
Sugar and other core activities. The latter could, one day, be replaced
by PyGI and GTK 3.0, which promises lower memory usage, but until now we
have no numbers backing this claim.

-- 
Bernie Innocenti
Sugar Labs Infrastructure Team
http://wiki.sugarlabs.org/go/Infrastructure_Team