Resource manager architecture

Here is the heart of a resource manager:

initialize the dispatch interface
register the pathname with the process manager
DO forever
    receive a message
    SWITCH on the type of message
        CASE io_open:
            perform io_open processing
        CASE io_read:
            perform io_read processing
        CASE io_write:
            perform io_write processing
        .   // etc. handle all other messages
        .   // that may occur, performing
        .   // processing as appropriate

The architecture contains three parts:

  1. A channel is created so that client programs can connect to the resource manager to send it messages.
  2. The pathname (or pathnames) that the resource manager is going to be responsible for is registered with the process manager, so that it can resolve open requests for that particular pathname to this resource manager.
  3. Messages are received and processed.

This message-processing structure (the switch/case, above) is required for each and every resource manager. However, we provide a set of convenient library functions to handle this functionality (and other key functionality as well).