A computer program product comprising at least one of data storage and memory having computer useable program code stored therein for operating a library control of an automated data storage library subsystem, said subsystem comprising storage shelves configured to store data storage media, a plurality of data storage drives configured to mount, demount, read and write data with respect to data storage media, at least one robot accessor configured to transfer data storage media between said storage shelves and said data storage drives;
- said computer useable program code configured to, when executed on said library control, cause said library control to:
- detect the occurrence of selected error events involving data storage drives;
- categorize said error events into:
- 1) error events before and during a mount of a data storage media into a data storage drive;
- and
- 2) error events after a successful mount of a data storage media into a data storage drive;
- separately track successive error events of individual data storage drives in each of said categories, wherein a complete successful operation of said data storage drive breaks the chain of said successive error events, wherein said breaking of said chain of successive error events applies only to a category of error events to which said complete successful operation belongs;
- compare the number of said successive error events of a data storage drive in a category to a threshold;
- and
- upon said number of said successive error events reaching said threshold, place said data storage drive in a failed category.