Task definitions are used by a task scheduler and prioritizer to allocate task operation to a plurality of processing units. The task definition is an electronic record that specifies researching needed by, and other characteristics of, a task to be executed. Resources include types of processing nodes desired to execute the task, needed amount or rate of processing cycles, amount of memory capacity, number of registers, input/output ports, buffer sizes, etc. Characteristics of a task include maximum latency tome, frequency of execution of a task, communication ports, and other characteristics. An exemplary task definition language and syntax is described that uses constructs including other of attempted scheduling operations, percentage or amount of resources desired by different operations, handling of multiple executable images or modules, overlays, port aliases and other features.