Patent ID: 8745421

Claim:
A data storage device comprising: a power circuit configured and arranged to provide main power; a first solid-state memory circuit configured and arranged to maintain data in the absence of electrical power; a second memory circuit subject to data loss in the absence of electrical power; a storage circuit configured and arranged to store energy in a storage element and to provide the stored energy to the second memory circuit in response to a loss of main power; a test circuit electrically connected to the storage circuit to modify how much energy is stored on the storage element while monitoring power-providing capabilities of the storage element during the modification of energy stored, and provide, in response to a discharge of an amount of the stored energy, output data indicative of power-providing capabilities of the storage element, wherein the output data is indicative of the power-providing capabilities being below threshold levels; and a memory controller configured and arranged to: control, for received access requests, data transfers to the data storage device by temporarily storing, in the second memory circuit, data destined for the first solid-state memory circuit, and in response to the output data, set an amount of memory available for temporary storage in the second memory circuit.