Attachment mechanisms may be employed to attach accessory devices to electronic devices. The device guide includes a frame a frame having a plurality of network supports. 5 V with respect to the oxidation-reduction potential of lithium, and the surface of the conductive material is coated with a coating layer mainly formed of P, O, C and H. Metadata is generated for the memory blocks at a location other than between the memory blocks, which is used when allocating memory to satisfy an allocation request of approximately the size of the memory blocks.