Magnetic disk having reserve servo sectors and plural reserve tracks

A sector servo type magnetic disk having plural data recording tracks forming plural data recording track groups formed on a data recording surface, and servo sectors spaced at intermittent locations on the same data recording surface for head positioning, wherein each of said plural data recording track groups comprises N data recording tracks, N being determined by periodic servo marks arranged at each of said servo sectors, such that each of said data recording tracks may be individually distinguished, said magnetic disk comprising:

• reserve servo sectors having servo marks and servo signal patterns for head positioning, provided outside the outside circumference and inside circumference of said plural data recording track groups;
• and
• plural reserve tracks, each having an identification area in which at least a track identification code is recorded, provided outside the outside circumference and the inside circumference of said plural data recording track groups.