[sugar] Sugar datastore model

[Tony Anderson]

There is a use case that concerns me at the moment:

1. An activity that allows a student to build a slideshow with music and 
voice tracks based on images taken with the XO camera (as well as png, 
svg, jpg from the internet or school library). How does the activity 
find available images on their XO to show as thumbnails? How does the 
activity find available sound files (mp3, ogg) for the student to choose 
for the sound tracks. Assume the activity builds a SMIL file to specify 
the slideshow. How does the activity generate persistent links to the 
image and sound files for later playback?

2. Extend the above scenario to one in which a group of students 
collaborate to create a slideshow based on pictures and sound files they 
have on their own XOs. Suppose they pool their files into a commons. 
Does the commons consist of links to the files in their original 
locations (on different XOs)? Does the commons consist to files copied 
to the school server? How are persistent links from the SMIL file 
maintained in either case?

3. Suppose a student wants to take his XO home to show the collaborative 
slideshow to his parents. How does he/she request that the files 
referenced by the SMIL file be copied to his XO?

4. How does a student know how much of his Nand is used/free? How can 
some/all of his files be moved to the schoolserver. What impact does 
this have on persistent links to these files?

Tony