[sugar] 9.1 Proposal: Files

[Erik Garrison]

By reintroducing the concept of files to our systems we can simplify our
work in a number of areas relative to 8.2:

- Compatibility with existing applications:
One of the principal reasons that the tens of thousands of open source
applications that run on Linux aren't usable under Sugar is that we have
a custom API for saving data.  To make them usable we have to exert
developer effort for every ported application.  This does not scale and
is not sustainable as we are completely alone in this effort.
Furthermore, reintroducing files to our APIs will simplify the process
of running Sugarized apps in non-Sugar environments, and provide
consistency to users who use them both within Sugar and outside.

- Data access, user-perceived reliability:
Using files forces users to be intentional about saving data (they must
name their work).  This makes it easier for them to find things they
care about--- provided, of course, that they are taught how to save
files as students are in virtually all computer-based education.

- Resting on upstream stability:
Files are used virtually everywhere else in the computing world, and
most certainly in our upstream distributions.  Using files means we have
the same problems as upstream, and no more.  If there is a filesystem
integrity problem in the Linux kernel filesystem drivers we can more
readily expect the aid of upstream users and developers in resolving the
issue than we could expect such aid in the case of a custom data storage
system.

- Collaboration:
Many collaboration issues could be resolved by exposing file-based
asynchronous collaboration to users.  Files are the core component of
collaboration in every other computing environment in common use.  Using
them as a primary storage system will greatly simplify the process of
sharing between an XO and a non-XO.

- Hackability: