Because GFTAVMA calculates DASD tracks as a weighted average over time, all of the DASD track values in Figure 1 represent a weighted average based on the number of days the data set resided on the various levels of storage.

For example, a data set with 500 tracks and a size of 15MB resides on migration level 2. If it resided on migration level 2 for two-thirds of the sample, the Management Class Report would report its size as 10MB. The data set would also have spent one-third of its life on DASD using one-third of 500 tracks, which is 167 tracks of primary DASD.