Apparatus and method for storing track layout information for performing quick write operations

A method of validating an update write operation as a quick write operation for a data track, comprising:

• determining if layout information for the data track is present in a cylinder table;
• if layout information for the data track is present in the cylinder table, determining if a data track block size for the data track is equal to a cylinder table entry block size;
• validating the update write operation as a quick write operation if the data track block size is equal to the cylinder table entry block size;
• and
• wherein if layout information for the data track is not present in a cylinder table, a determination is made as to whether the data track is a candidate for future quick write operations.

A method of creating a cylinder table for a direct access storage device, comprising:

• determining if a data track is a candidate for a future quick write operation;
• creating a cylinder table entry for a cylinder corresponding to the data track if the data track is determined to be a candidate for a future quick write operation;
• and
• wherein determining if the data track is a candidate for a future quick write operation includes determining if a number of records in the data track are greater than one and determining if a record length of a record in position zero is a predetermined size.

A computer program product in a computer readable medium for validating an update write operation as a quick write operation for a data track, comprising:

• first instructions for determining if layout information for the data track is present in a cylinder table;
• second instructions for determining if a data track block size for the data track is equal to a cylinder table entry block size, if layout information for the data track is present in the cylinder table;
• third instructions for validating the update write operation as a quick write operation if the data track block size is equal to the cylinder table entry block size;
• and
• wherein the first instructions further include fourth instructions for determining whether the data track is a candidate for future quick write operations, if layout information for the data track is not present in a cylinder table.

A computer program product in a computer readable medium for creating a cylinder table for a direct access storage device, comprising:

• first instructions for determining if data track is a candidate for a future quick write operation;
• second instructions for creating a cylinder table entry for a cylinder corresponding to the data track if the data track is determined to be a candidate for a future quick write operation;
• and
• wherein the first instructions include third instructions for determining if a number of records in the data track are greater than one and determining if a record length of a record in position zero is a predetermined size.