The disk status is returned in combinatin of following flags.
STA_NOINIT
Indicates that the disk drive has not been initialiezed. This flag is set on: power-on, disk removal and disk_initialize function failed, and cleared on: disk_initialize function succeeded.
STA_NODISK
Indicates that no medium in the drive. It is always cleared on fixed disk drive.
STA_PROTECTED
Indicates that the medium is write protected. It is always cleared on the drive that does not support write protect notch.