1. A method implemented on a computer, the method comprising: providing runtime services, including a virtual file system, to a first program running on the computer and a second program running on the computer, providing the runtime services comprising: receiving, from the first program, first information and second information through a single file access routine of an application program interface (API) for the virtual file system; determining one of multiple file storage areas to access based on the first information, the multiple file storage areas including a first area and a second area, the first area being local to the computer and accessible by the first program through the virtual file system, the first area further being inaccessible by the second program through the virtual file system, the second area being accessible by the first program and the second program through the virtual file system; mapping the second information to one or more file resources in the determined file storage area in the virtual file system; and accessing the one or more file resources for the first program.