A system, method and program product for determining a history state of data in a data retaining device are disclosed. A state of a partially-depleted silicon-on-insulator (PD SOI) device coupled to a data retaining device is measured to indicate a body voltage of the PD SOI device. The body voltage of the PD SOI device may indicate, among others, how long the PD SOI device has been idling, which indirectly indicates how long data in the data retaining device has not been accessed. As such, the current invention may be used efficiently with, e.g., a cache replacement algorithm in a management of the data retaining device.