16 in embodiments in which each individual application controls their own power saving mode operation 16 may be performed asynchronously by each application an application may determine if it is time to perform a data update by comparing the current time maintained by the operating system with its next scheduled data update time which was stored earlier at operation 14 in embodiments in which the operating system controls updates for each application that is in a power saving mode operation 16 is performed synchronously by the operating system for each active application the operating system may determine if it is time to perform a data update for a given active application by querying a database for scheduled data updates see operation 14 that occur at or before the current time based on this comparison the operating system may create a list of applications that are scheduled to update data operation 16 repeats until at least one application or widget is to update its data in one embodiment operation 16 repeats at a set interval e g every 5 seconds upon the determination that an application or widget is to update its data now operation 18 determines if the portable electronic device 1 is in a sleep state as described above the portable electronic device 1 is in a sleep state when the display screen is turned off conversely when the display screen is turned on the portable electronic device 1 is in a wake state operation 18 continues to operate until the portable electronic device 1 is determined to not be in a sleep state in embodiments.