8.4 RTOS Support for Distribution

Other than mapping the interface ID to the physical ports, the name database and inter- card messaging functions are quite general. Some RTOSes offer these as part of their distribution. For example, the OSE™ RTOS provides a facility called the Name Server, which tracks the physical paths to system services. This allows OSE applications to use logical names for communicating with any service. If there is a change in the distributed system topology, the Name Server is updated. So, applications will not notice any disruption, as they will always use the name for communicating with the services.

OSE also offers a facility called the Link Handler, which can be used to implement the DAL messaging function. The Link Handler keeps track of all resources within a dynamic distributed system. If a process fails, the OSE Link Handler notifies all processes that were communicating with the failed process. The communicating processes can take action on this notification. The Link Handler also notifies the Name Server of the availability or non-availability of resources.