Critical task scheduling for real-time systems

Claim 3

The method of claim 1, wherein said resource is dynamically allocated and reclaimed memory.

Claim 4

The method of claim 2, and further comprising the step of scheduling a garbage collection task.

Claim 5

The method of claim 2, wherein said counting step and said comparing step are linked to a local allocator of a program executing said task.

Claim 6

The method of claim 1, wherein said resource is a communications link having a capacity of n bits per second.

Claim 7

The method of claim 1, wherein said task is a critical task, such that said maximum allocation value has been determined to permit said task to meet system deadlines.

Claim 8

The method of claim 1, wherein said task is a non critical task and said maximum allocation value has been determined so that said non critical task will not prevent timely execution of critical tasks.

Claim 9

The method of claim 1, wherein said task executes within a time slice of a processor of said computer system, and said task is required to discontinue execution if either said time slice has expired or said counter value exceeds said maximum allocation value.

Claim 10

The method of claim 1, and further comprising the step of dynamically adjusting said maximum allocation value.

Claim 11

A computer system for executing application programs in hard real time and programmed with automatic memory management programming, comprising: a central processing unit for executing application programs and operating system programs; a computer memory for storing said programs and data operated on by said programs; a garbage collector for reclaiming memory allocated by said application programs; a counter for incrementing an allocation value according to the allocation requests of a current task of said program; a comparator for comparing the current value of said counter to a maximum allocation value stored in said memory and associated with said current task; and a scheduler for determining which tasks are to be processed by said central processing unit, wherein said scheduler receives a signal from said comparator if said counter value exceeds said maximum allocation value, and in response to said signal, causes said current task to temporarily cease execution.

Claim 12

The system of claim 10, wherein said counter and said comparator are software routines linked to a local allocation routine of said automatic memory management programming.

Claim 13

The system of claim 10, wherein said counter and said comparator are implemented as hardware devices.

Claim 14

A task controller for a real time embedded computer system having a resource that is consumed in bits per unit of time, comprising: a memory for storing maximum allocation values for tasks to be executed by the computer system; a counter for counting allocation requests of a currently executing task; a comparator for comparing a maximum allocation value of said currently executing task with the output of said counter; communication means for delivering a signal to a system scheduler, if said output of said counter exceeds said maximum allocation value, with respect to said currently executing task.

Claim 15

A task controller for a real time embedded computer system having a resource that is consumed in bits per unit of time, comprising: a memory for storing maximum allocation values for tasks to be executed by the computer system; a counter for counting allocation requests of a currently executing task; a comparator for comparing a maximum allocation value of said currently executing task with the output of said counter; communication means for delivering a signal to a system scheduler, if said output of said counter exceeds said maximum allocation value, with respect to said currently executing task.

Claim 16

The task controller of claim 13, wherein said counter and said comparator are software routines linked to local allocation routine of said automatic memory management programming.

Claim 17

The task controller of claim 13, wherein said counter and said comparator are implemented as hardware devices.

Claim 18

The task controller of claim 13, wherein said resource is dynamically allocated memory.

Claim 19

The task controller of claim 16, and further comprising a schedule for scheduling a garbage collection task.

Claim 20

The task controller of claim 13, wherein said resource is a communications link having a capacity of n bits per second.

Claim 21

The task controller of claim 13, wherein said task is a critical task, such that said maximum allocation value has been determined to permit said task to meet system deadlines.

Claim 22

The task controller of claim 13, wherein said task is a non critical task and said maximum allocation value has been determined so that said non critical task will not prevent timely execution of critical tasks.