Real time clock using computer and separate counting means
Method and system for keeping time across a multiprocessor platform
Method and apparatus utilizing a flash memory device to maintain accurate unit timing Patent #: 6167482
ApplicationNo. 10411455 filed on 04/10/2003
US Classes:713/500, CLOCK, PULSE, OR TIMING SIGNAL GENERATION OR ANALYSIS713/502, Counting, scheduling, or event timing377/32, Power failure713/400, SYNCHRONIZATION OF CLOCK OR TIMING SIGNALS, DATA, OR PULSES711/103Programmable read only memory (PROM, EEPROM, etc.)
ExaminersPrimary: Browne, Lynne H.
Assistant: Yanchus, III, Paul
Attorney, Agent or Firm
Foreign Patent References
International ClassG06F 1/14
AbstractMethods, apparatus, systems, and articles of manufacture for maintaining virtual real time clocks (virtual RTCs) in a logically partitioned computer system are described. Changes made to a hardware real time clock (hardware RTC) while a partition manager is not running (or is not fully operational) are tracked. The cumulative effect of these changes on the hRTC value may be captured in a clock delta variable. For some embodiments, a service processor may be configured to track the changes to the hRTC while the partition manager is not running and generate the clock delta. Upon loading, the partition manager may utilize this captured clock delta to make adjustments to vRTCs, in an effort to preserve their integrity by compensating for the changes made to the hRTC while the partition manager was not running.