Event based operating system, method, and apparatus for instrumentation and control systems

A non-transitory machine readable medium having recorded thereon instructions or therein a non-preemptive operating system, the instructions executable by a processor having a number of timers to thereby control a plurality of events greater than the number of said timers, to:

• between clock ticks, receive one or more signals indicating that an event is inactive, waiting or executing from sensors, switches, executing programs or a combination thereof that initiate one or more timed events, the timed events including inactive events, active events, pending events, executing events, and waiting events;
• on or after a clock tick immediately following said receiving of one or more signals, update entries in an event control block in accordance with said received signal or signals, said entries including a time remaining for pending events, a time past due for active events, a priority of each timed event and indications of whether said events of the plurality of events are inactive, waiting, pending, active, or executing, wherein said updating further include updating a shadow semaphore within said operating system on a clock tick, and using said shadow semaphore to reprioritize past due events;
• determine whether any pending event or events have timed out and activating any timed-out events;
• send a signal notifying an executing program of an activated event having a highest priority;
• and
• increase priorities of past due active events that have not yet been signaled to the executing program.

A controller comprising a processor having a number of timers to thereby control a plurality of events greater than the number of said timers and memory including instructions executable by said processor, on said controller to:

• between clock ticks, receive one or more signals indicating that an event is inactive, waiting or executing from sensors, switches, executing programs or a combination thereof that initiate one or more timed events, the timed events including inactive events, active events, pending events, executing events, and waiting events;
• on or after a clock tick immediately following said receiving of one or more signals, to update entries in an event control block in accordance with said received signal or signals, said entries including a time remaining for pending events, a time past due for active events, a priority of each timed event, and indications of whether said events of the plurality of events are inactive, waiting, pending, active, or executing, wherein said updating further include updating a shadow semaphore within said operating system on a clock tick, and using said shadow semaphore to reprioritize past due events;
• determine whether any pending said event or events have timed out and activating any timed-out events;
• send a signal notifying an executing program of an activated event having a highest priority;
• and
• increase priorities of past due active events that have not yet been signaled to the executing program.