Task control means for a multi-tasking data processing system

TL;DR: In this paper, a task control method and apparatus for controlling the interactive, concurrent execution of a plurality of general purpose data processing tasks in a data processing system is presented, which includes a memory for storing active tasks, a mass storage means for storing inactive tasks and a general purpose CPU.

Abstract: A task control method and apparatus for controlling the interactive, concurrent execution of a plurality of general purpose data processing tasks in a data processing system. The system includes a memory for storing active tasks, a mass storage means for storing inactive tasks and a general purpose CPU. Upon request by a user or by an active task, a task loader transfers a presently inactive task from the mass storage means to the memory to be available for execution. A memory manager assigns a task node space in the memory and a task manager creates a task control block for the task to be activated, assigns a task control block identification to the task control block, and writes the task control block identification into the task's task node space to link the task to the task's task control block. The task manager includes a plurality of task queues, each queue corresponding to a relative priority level for execution of the tasks, and each task control block is stored in a task queue corresponding to the task's priority level. The sequence of the task control blocks in each task queue is dependent upon the status of execution of the corresponding task. Tasks are executed in a sequence depending upon the relative priorities of the task queues and upon the sequential locations of the task control blocks in a task queue.