A secondary memory unit includes a first substrate that has a non-volatile memory unit mounted thereon that is configured to receive power from an external power supply. A second substrate has an energy storage and supply medium mounted thereon. An energy transfer medium is provided that electrically connects the first substrate and the second substrate. The energy storage and supply medium is configured to supply an operating power to the non-volatile memory unit when power from the external power supply to the non-volatile memory unit is cut off.