Adjustable sub-regions for shingled magnetic recording

A method of operating a Data Storage Device (DSD), the method comprising:

• shingle writing data in a first sub-region of a region on a disk such that adjacent tracks partially overlap each other to reach a first predetermined data storage capacity for the first sub-region;
• determining whether a predetermined data storage capacity for the region can be reached by adding a first sub-region guard band and shingle writing throughout a remaining available portion of the region using a lower limit of track overlap of adjacent tracks,
• wherein the first sub-region guard band is designated to not store data and separates the first sub-region from a second sub-region of partially overlapping tracks in the region;
• and
• in response to determining that the predetermined data storage capacity for the region can be reached by adding the first sub-region guard band and shingle writing with the lower limit of track overlap throughout the remaining available portion of the region:
• adding the first sub-region guard band in the region;
• and
• shingle writing in the second sub-region with at least as much track overlap as the lower limit of track overlap.

A Data Storage Device (DSD), comprising:

• a disk configured to store data;
• a head configured to write data on the disk in tracks;
• and
• means for:
• shingle writing data in a region on the disk using the head such that adjacent tracks partially overlap each other to define a track pitch between centers of non-overlapped portions of the adjacent tracks;
• determining whether shingle writing data in a remaining available portion of the region with an upper limit track pitch would leave enough space for a first sub-region guard band in the region and still reach a predetermined data storage capacity for the region,
• wherein the first sub-region guard band is designated to not store data and separates a first sub-region including shingle written tracks with a first track pitch from a second sub-region to be shingle written;
• and
• in response to determining that shingle writing data in the remaining available portion with the upper limit track pitch would leave enough space for the first sub-region guard band in the region and still reach the predetermined data storage capacity for the region:
• adding the first sub-region guard band in the region;
• and
• shingle writing in the second sub-region using the head.