Patent ID: 7509533

Claim:
In a computerized device having a first processing device, a second processing device, and an interconnection mechanism allowing communication between the first and second processing devices, a method for testing a processing device, the method comprising: operating the first processing device in a normal processing mode; transitioning the first processing device from the normal processing mode to an isolated processing mode; performing a test process on the first processing device while in isolated processing mode to test functional portions of the first processing device, wherein the test process is repeated on the first processing device after one or more periodic intervals of time, the duration of the intervals being less than or equal to a mean time between failure of devices equivalent to the first processing device; and if operation of the test process produces an error in a functional portion of the first processing device, notifying a control process on a second processing device of the error in the functional portion of the first processing device in which the test process produced an error; if operation of the test process does not produce an error in the functional portions of the first processing device, transitioning the first processing device from the isolated processing mode back to the normal processing mode upon completion of the test process; wherein the first and second processing devices are central processing units of a plurality of central processing units in the computerized device that is configured with N+I central processing units; and wherein testing operations of operating in a normal processing mode, transitioning to an isolated processing mode performing the test process, notifying a control process and transitioning back to the normal processing mode are repeatedly performed for each respective central processing unit in a constant manner during a testing time assigned to that central processing unit, such that there can be N central processing units operating in normal processing mode while one processing unit is operating the test process in isolated processing mode.