A thread-dispatching kernel for event-driven applications

Summary form only given. The design of a real-time executive that embodies some novel concepts and the rationale of choices in the design of that executive are the focus of this work. The application is a data communication environment, in which the executive resides on an M68000-based programmable communications (PROCOM) board. One or more PROCOM boards will augment concurrent 3200-series computers functioning as nodal elements in ARINC´s packet switching network. The PROCOM board will support the link-level component of the network protocol, adding capacity to process and switch message traffic. A major design objective was to reduce the executive overhead below the level usually present in traditional multitasking executives. The kernel uses thread dispatching and no-waited I/O to maximize real-time performance. The design details of the following real-time operating system components are outlined: (a) the kernel and its main services, (b) the event subsystems servicing the host side and the network side, and (c) the device drivers servicing the DMA transfer controllers, the serial communication controllers, and the host-PROCOM interface