TD History is a WINDOWS based system that provides information required for the optimization of tape data set use in an MVS environment.

The primary use of the system is to:

• identify volume of data that could be managed more efficiently on DASD, Virtual Tape, or larger tape media
• generate filter lists that are used in simulations to collect size and use characteristics for each entry
• run simulations against a database of tape data set information, obtained from SMF records, to categorize the use of data sets by user provided size and time to recall
• identify data sets that should be recalled to DASD or TVC, prior to running batch jobs, to avoid delays in execution

This is accomplished by:

• running a size simulation requesting generated filter lists by data set size
• simulating small data set filter list entries on a logical queue to obtain recall characteristics and create filters with similar reuse requirements
• running simulations to identify optimum retention period and cache size for VTS or DASD space required to support identified workload
• running simulations on data sets recalled after one day to identify filter entries that should not be put on VTS to avoid thrashing.