Disk-shaped recording medium and formatting method thereof wherein historic information including a storage capacity of the disk-shaped recording medium is recorded thereon

This invention relates to a magnetic recording medium such as a flexible or floppy disk (which may be abbreviated to "FD") for use in a removable type magnetic recording/reproducing device such as a flexible or floppy disk drive (which may be abbreviated to "FDD") and a format method thereof. In a large-capacity FD comprising a disk-shaped recording medium on which a plurality of tracks are arranged with concentric circles, each track is divided into a predetermined number of sectors having a length equal to one another. Each sector consists of a serve field and a data field. The servo field in each sector includes a sector number field in which a sector number and alternation contents of the magnetic disk medium are written and a track number field in which a track number is written. The sectors on each track may be assigned with serial sector numbers in a circumferential direction in order with skipping over any defective sector. The plurality of tracks may be separated in a radial direction into a plurality of zones each including at least one alternate track. The plurality of tracks may be separated in a radial direction into a user data area and an alternate area which has an information identification sector for storing historic information in respect to preparation of the disk-shaped recording medium.