Patent ID: 8438415

Claim:
A method of steering a time of day (TOD)-clock for a shared storage multiprocessing environment comprising multiple processing units, each unit having associated physical clock synchronized by means of a common oscillator stepping pulse, said method comprising the steps of: receiving, at a processing unit, a request to change a clock steering rate used to control a TOD-clock offset value for said processing unit, said TOD-clock offset defined as a function of a start time (s), a base offset (b), and a steering rate (r); assigning, based on said received request, a new-episode start time value, new-episode base offset value, new-episode fine-steering rate value; and a new-episode gross-steering rate value; detecting a time instance of said physical clock reaching said new-episode start time value; and, automatically switching a TOD-clock to use the new-episode start time, new-episode base offset and new-episode fine and gross-steering rate values by computing a TOD clock-offset value in the new episode, where said computed TOD clock-offset value is added to a physical clock to obtain an adjusted basic-machine TOD clock value without adjusting a stepping rate of said oscillator.