A memory device and techniques for its operation are presented. After operating on power received from a host, the memory device determines that it is no longer receiving host power and, in response, activates a power source on the memory device itself. Using this reserve power, the memory device can then perform data management operations. The techniques can also be applied to a digital appliance having a non-volatile memory. The memory device or digital appliance can prioritize its memory management operation during the host/user operating window based on the ability to perform these operations outside of the host/user operating window. Additionally, in a data write operations, where the memory device receives data from a host, stores the data in volatile memory, and then writes the data into the non-volatile memory, the memory device sends the host an acknowledgment of the data having been written into the non-volatile memory after it has been store in the volatile memory, but before the write into the non-volatile memory is complete.