Programming execution-time servers in Ada 2005

Much of the research on scheduling schemes is prevented from being used in practice by the lack of implementations that provide the necessary abstractions. An example of this is the support of execution-time servers. Apart for a single mechanism (the Sporadic Server), which is defined in the POSIX standard, these important building blocks are not available to the system developer. Over the last few years, we have been developing the mechanisms necessary to construct execution-time servers from within an Ada context. Versions of these have now been incorporated in the Ada 2005 standard. In this paper, we show how the mechanisms can be used to construct the Deferrable and Sporadic servers.