Customizing a range of acceptable tape dimensional stability write conditions

A tape drive comprising:

• a head having a plurality of read and write elements and a plurality of servo elements;
• and
• a drive control system for moving tape across said head;
• wherein said tape drive is operative to:
• determine if said tape has expanded or contracted in a lateral direction;
• if said tape has expanded in said lateral direction, then:
• determine an amount of expansion;
• determine if a sum of said amount of expansion and a maximum acceptable amount of contraction is less than a predetermined threshold value;
• store said amount of expansion as said maximum acceptable amount of expansion if said sum of said amount of expansion and said maximum acceptable amount of contraction is less than said predetermined threshold value;
• and
• if said tape has contracted in said lateral direction, then:
• determine an amount of contraction;
• determine if a sum of said amount of contraction and a maximum acceptable amount of expansion is less than said predetermined threshold value;
• and
• store said amount of contraction as said maximum acceptable amount of contraction if said sum of said amount of contraction and a maximum acceptable amount of expansion is less than said predetermined threshold value.

A computer implemented method of evaluating acceptable write conditions on tape of a tape cartridge in response to a write request, the method comprising:

• determining if the tape has expanded or contracted from a nominal dimension in a lateral direction;
• determining an amount of expansion or an amount of contraction of said tape from a nominal dimension;
• determining if a first sum of said amount of expansion and a first stored amount of contraction is be greater than a predetermined threshold value if it is determined that the tape has expanded, or determining a second sum of said amount of contraction and a first stored amount of said expansion is greater than said predetermine threshold value if it is determined that the tape has contracted;
• disallowing said write request if said first sum or said second sum is greater than said predetermined threshold value;
• and
• allowing said write request if said first sum or said second sum is not greater than said predetermined threshold value and storing said amount of expansion or said amount of contraction if said determined amount of expansion is greater than said first stored amount of said expansion or said amount of contraction is greater than said first stored amount of said contraction, respectively.