Utilization of Non-Volatile Memory System Battery to Maintain Independent Real Time Clock.
Original Publication Date: 2004-Dec-02
Included in the Prior Art Database: 2004-Dec-02
In most modern storage systems there is a need for the system to have a concept of date and time that is associatable with the actual calendar and wall time of the users and other systems. To avoid having the user tell the system what the date and time is each time the system is powered on, it is now customary for the systems to have a clock/calendar integrated circuit (RTC or real-time-clock) that is powered from a battery to keep track of time during the periods of time when the system is powered off. In general, batteries are items that it is preferable to avoid in a system. They have limited life span and there are significant ecological concerns with thier composition which leads to the necessity of expensive recycling programs to prevent the battery cells from entering the waste stream. This invention provides power to the RTC in such a manner as to avoid adding an additional batteries or battery system to a midrange RAID controller. The current art is to add a separate battery for the RTC or have an external system set the time in the controller on each power on.