Enabling Your File System to HFS

To make your file system available for use with the HFS APIs, take these steps:

1. Read Standard HFS API and Exit Program Functions carefully. It describes which functions the HFS APIs perform for you and which functions your file system's exit programs must perform.
   
   
2. Define your own file and directory objects. These objects can be any of the following:
   
   
   • i5/OS^(TM) objects, such as user spaces and user indexes
   • Objects on external devices attached to your iSeries^(TM) server
   • Objects on other systems that are attached to your iSeries server by communications lines

   Your file system controls the structure, format, and location of the file and directory objects it defines. It also controls security and authority for those objects.

3. Create these programs:
   
   
   • A program or command to call the Register File System (QHFRGFS) API, which enrolls the file system for use with the HFS APIs.
   • A Start Job Session exit program, which is called the first time a job tries to use the file system. See Start Job Session Exit Program for details.
   • An End Job Session exit program, which is called at job end to perform job cleanup. See End Job Session Exit Program for details.
   • An exit program for every HFS API function that you want your file system to support. For a list of exit programs you can supply, see the list of qualified exit program names parameter in the Register File System (QHFRGFS) API. If your file system is written in a high-level language that supports a variable number of input parameters, you can specify the same exit program for more than one function.

     Your file system does not need to support every function. However, if you supply an Open Stream File or Open Directory function to support the QHFOPNSF or QHFOPNDR API, you must supply the corresponding close function.

4. Register your file system with HFS, specifying the exit programs you want to make available. See Register File System (QHFRGFS) API for complete instructions.
   
   
5. Give the file system's users authority to the Start Job Session Exit Program. Authority to this program gives users authority to the file system as a whole.
   
   
6. Give the file system's users authority to the HFS APIs that you support with exit programs and that you want to make public. A user needs *USE authority to an API to call the API from a program.
   
   
7. Provide the file system's users with complete documentation, so they know which HFS APIs are supported, and whether any of the HFS APIs work differently from the way they are described in this information.