A data storage device, such as a disk drive, includes a disk that is coated with a magnetic material which is magnetized with a write element (e.g., a write coil) in order to record information onto the surface of the disk. Various influences may render portions of the disk surface defective, for example, if the magnetic coating is not evenly applied to the disk surface, or if a particle contaminates the magnetic coating. During a manufacturing procedure, the disk drive may be hooked up to a test system and the defective areas of the disk and certain areas adjacent the defective areas (i.e., unusable areas) are located and “mapped out” so that they are not used during normal operation. These defective and unusable areas can reduce a storage capacity of the disk. The disk, however, may need to have a minimum amount of storage capacity.
During a formatting process an amount of space used by the defective and unusable areas of the disk dictates whether there is enough storage capacity in the disk. When the amount of space used by the defective and unusable areas exceeds a predetermined threshold, there is a storage capacity error. When the disk drive determines that there is a storage capacity error during the formatting process, disk drive will transmit a storage capacity error signal to the test system.
Since the discovery of the storage capacity error occurs during the formatting process, the disk drive could be connected to the test system for a long time before the storage capacity error is discovered. This can limit an amount of disk drives tested by the test system.