Machine control using a schedulerlock construct

• US 6,678,713 B1
• Filed: 04/29/1998
• Issued: 01/13/2004
• Est. Priority Date: 04/29/1998
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Vanduyn, Robert M., Dixon, Michael D., Ferraro, Robert P., Mason, Raymond I., Des rivieres, James J., Beaman, Thomas G.
• Primary Examiner(s): BULLOCK JR, LEWIS ALEXANDER
• Application Number:
  US09/069,038
• Time in Patent Office: 2,085 Days
• Field of Search: 709/102, 709/318, 709/400, 709/315, 709/100-108, 709/310, 710/5-7, 710/59, 710/58
• US Class Current: 718/102
• CPC Class Codes: G03G 15/5012 Priority interrupt; Job recovery, e.g. after jamming or malfunction
• CPC Class Codes: G05B 19/0426 Programming the control sequence

Abstract

A method of use of real time machine control software integrating both event based mode and task based components. In particular, a collection of constructs have been created that allow machine control applications to be expressed in event based terms and the event based constructs to be seamlessly integrated with task based constructs. The method includes the use of response time specifications, in particular in conjunction with ReactiveTask and Task constructs. The method also includes the use of Register, ReferenceClock, and SchedulerLock constructs.

Claims

1. In an electronic image processing apparatus comprising a controller and a plurality of modules with devices having input and output functions for creating image impressions, the controller including a plurality of constructs including ReactiveTask for responding to external events, Events representing defined abstractions of physical and logical events, NonReactiveTask providing threads of execution, Registers for providing a common resource for ReactiveTasks, and SchedulerLocks for facilitating synchronization and shared data access control, a method of control comprising the steps of:

invoking multiple ReactiveTask constructs in response to an event and attaching the ReactiveTask to all associated Events,

providing data in a Register construct capturing a common state requiring access by multiple ReactiveTask constructs, the Register construct providing access protection, and

inhibiting the preemption of currently executing tasks by the SchedulerLock construct to facilitate synchronization.

2. The method of claim 1 wherein the SchedulerLock construct including a constructor for disabling interrupts and a destructor for ending the disabling of interrupts.

3. The method of claim 1 wherein if multiple SchedulerLock objects are in existence, the step of enabling interrupts upon the completion of all said multiple SchedulerLock objects.

4. The method of claim 1 the step of automatically destroying a SchedulerLock construct upon completion of a scope of a block in which the SchedulerLock construct was created.

5. In an electronic image processing apparatus comprising a controller and a plurality of modules with devices having input and output functions for creating image impressions, the controller providing interrupts, a method of shared data access control comprising the steps of:

providing a short term interrupt disable for completion of specific tasks,

monitoring the completions of said specific tasks, and

responding to the completions of said specific tasks, to immediately re-enable the interrupts.

6. The method of claim 5 wherein for multiple tasks requiring a short term interrupt disable, the step of enabling interrupts upon the completion of all said multiple tasks.

7. The method of claim 5 including the step of automatically destroying a SchedulerLock construct when a scope of a block in which the SchedulerLock construct was created exits.

8. The method of claim 5 wherein the short term interrupt disable is a control construct.