Dynamic band boundaries

An apparatus comprising:

• a controller configured to:
• restructure a first band of multiple data tracks including a first sequence of circumferentially adjacent data sectors of a data storage medium to include a selected sector from a first guard area to produce a shifted first sequence,
• the first guard area disposed between the first band and a second band of multiple data tracks including a second sequence of circumferentially adjacent data sectors such that no sector of the first sequence is directly adjacent to a sector of the second sequence,
• the first guard area comprising sectors not designated for storing data;
• and
• designate the selected sector for storing data.

A device comprising:

• a data storage apparatus including:
• a data storage medium having:
• a plurality of bands of multiple tracks configured to store data in a shingled manner where one track partially overlaps an adjacent track;
• guard areas disposed between bands so that no sector of one band is adjacent to a sector in another band, a guard area including:
• a plurality of sectors designated as not for storing user data;
• a first spare sector;
• and
• a controller configured to:
• shift a boundary of a first band by converting the first spare sector to a usable data sector of the first band.