Method of driving head, head driving device and disc driving apparatus using the same method and device

A head driving device comprising:

• (a) a head for accessing to a disc;
• (b) target-sector-accessible-time calculation means for determining a minimum integer N holding a relation:
• (a target-sector-accessible-time)≧(a shortest time within which a head moves to a track including a target sector),
• when a sector-arrival-time is defined as a necessary time from an instance the head starts moving to the track including the target sector to another instance a disc rotates thereby the target sector arrives at a position accessible by the head for a first time, and the target-sector-accessible-time is a sum of the sector-arrival-time and a latency which is obtained by multiplying a disc-rotation-period by an integer N (zero or greater than zero);
• (c) control means for moving the head by determining a moving-speed and an acceleration/deceleration pattern so that the head finishes a head-moving and a head-positioning to the track including the target sector within the target-sector-accessible-time determined by substituting the integer N.

A disc driving apparatus comprising:

• (a) a spindle device for rotating a disc;
• (b) a head driving device;
• said device comprising:
• (b-1) a head for accessing to the disc;
• (b-2) target-sector-accessible-time calculation means for determining a minimum integer N holding a relation:
• (a target-sector-accessible-time)≧(a shortest time within which the head moves to a track including a target sector),
• when a sector-arrival-time is defined as a necessary time from an instance the head starts moving to the track including the target sector to another instance a disc rotates thereby the target sector arrives at a position accessible by the head for a first time, and the target-sector-accessible-time is a sum of the sector-arrival-time and a latency which is obtained by multiplying a disc-rotation-period by an integer N (zero or greater than zero);
• (b-3) control means for moving the head by determining a moving-speed and an acceleration/deceleration pattern so that the head finishes a head-moving and a head-positioning to the track including the target sector within the target-sector-accessible-time determined by substituting the integer N.