Apparatus and method to form one or more premigration aggregates comprising a plurality of least recently accessed virtual volumes

[0018]Referring to the illustrations, like numerals correspond to like parts depicted in the figures. The invention will be described as embodied in a virtual tape server in combination with an automated data storage and retrieval subsystem for use in a data processing environment. The following description of Applicant's apparatus and method is not meant, however, to limit Applicant's invention to either data storage and retrieval systems, or to data processing applications, as the invention herein can be applied to data storage in general.

[0019]FIG. 3 illustrates the hardware and software environment in which preferred embodiments of the present invention are implemented. Virtual tape server (VTS) 300 is pictured, operatively coupled to a host computer 390. In certain embodiments, host computer 390 comprises a single computer. In alternative embodiments, host computer 390 comprises one or more mainframe computers, one or more work stations, one or more personal computers, combination