Mobile Python: Rapid Prototyping of Applications on the Mobile Platform

A.3. File System Protection

Besides the limitations described previously, access to some files is limited. There are three protected directories on each drive that have special properties. The protected directories are:

• \sys: Requires AllFiles to read, TCB to write.

  The most important part here is the \sys\bin directory since, under Platform Security, the phone can only execute native code in the \sys\bin directories. On previous S60 editions it was possible to store C++ extension modules for PyS60 in any directory, but in S60 3rd Eition they must all be stored in \sys\bin.

• \resource: Requires TCB to write and no capabilities to read.

  This directory is used for storing shared, non-sensitive data that must be accessible to several programs. Python for S60 comes with a set of standard library modules written in Python and they are stored here.

• \private: Reading and writing to a program's own directory needs no capabilities. Reading other programs' directories requires AllFiles and writing to them requires TCB.

All other parts of the file system (for example, \data\images) can be freely read and written by all code. regardless of capabilities.

If you need to store program-specific data that must be easily accessible and writable by anyone, storing it in a program-specific subdirectory under \data is a good choice. The Nokia PC Suite file manager is able to access the entire contents of the memory card, but only the C:\data directory on the C: drive. The ability to use the file manager ...