Consideration of adjacent track interference and wide area adjacent track erasure during block allocation

A computer system for allocating a block of physical storage space on a write surface of a hard disk drive, the system comprising:

• one or more processors, one or more computer-readable memories, one or more computer-readable tangible storage devices, and program instructions stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, the program instructions comprising:
• program instructions to maintain a write count for each block on the hard disk drive, wherein a write count is a cumulative number of write operations performed on a block of storage space;
• program instructions to receive an allocation request for a block of storage space on the hard disk drive;
• program instructions to identify one or more candidate blocks of storage space on the hard disk drive that can be selected to fulfill the allocation request;
• program instructions to determine an estimated write count, wherein the estimated write count is an estimated number of write operations that will be performed on any candidate block that is subsequently selected from the one or more candidate blocks to fulfill the allocation request;
• program instructions to identify one or more allocated blocks of storage space on the hard disk drive whose write counts are within a specified number of write operations of the estimated write count;
• program instructions to select a candidate block from the one or more candidate blocks based, at least in part, on physical proximity of the candidate block to one or more of the one or more allocated blocks of storage space on the hard disk drive whose write counts are within a specified number of write operations of the estimated write count, such that the selected candidate block is at least on a track adjacent to a track of at least one of the one or more allocated blocks of storage space on the hard disk drive whose write counts are within a specified number of write operations of the estimated write count;
• and
• program instructions to allocate the selected candidate block to fulfill the allocation request.

A computer program product for allocating a block of physical storage space on a write surface of a hard disk drive, the computer program product comprising:

• one or more computer-readable tangible storage devices and program instructions, executable by a computer processor and stored on at least one of the one or more storage devices, the program instructions comprising:
• program instructions to maintain a write count for each block on the hard disk drive, wherein a write count is a cumulative number of write operations performed on a block of storage space;
• program instructions to receive an allocation request for a block of storage space on the hard disk drive;
• program instructions to identify one or more candidate blocks of storage space on the hard disk drive that can be selected to fulfill the allocation request;
• program instructions to determine an estimated write count, wherein the estimated write count is an estimated number of write operations that will be performed on any candidate block that is subsequently selected from the one or more candidate blocks to fulfill the allocation request;
• program instructions to identify one or more allocated blocks of storage space on the hard disk drive whose write counts are within a specified number of write operations of the estimated write count;
• program instructions to select a candidate block from the one or more candidate blocks based, at least in part, on physical proximity of the candidate block to one or more of the one or more allocated blocks of storage space on the hard disk drive whose write counts are within a specified number of write operations of the estimated write count, such that the selected candidate block is at least on a track adjacent to a track of at least one of the one or more allocated blocks of storage space on the hard disk drive whose write counts are within a specified number of write operations of the estimated write count;
• and
• program instructions to allocate the selected candidate block to fulfill the allocation request.