Figure 1 shows the possible effects of IDRC compaction, 3490E enhanced recording format, and the Enhanced Capacity Cartridge System Tape on large data sets.

Figure 1. The IDRC Report

 3  The target tape device is controlled by the TAPEDEV keyword, which was specified as 3490E, and the TAPELEN keyword, which was specified as 2. IDRCFACTOR was specified as 3.

 4  In the S/M FILE column, SNGL or MULT indicates whether a data set is single-file or multifile. See Single/Multi Volume/File Data Sets for more details.

 5  The MEGABYTES TRANSFERRED column is the size, in megabytes, of the current version of a data set. This size is used to calculate the number of target (TAPEDEV) volumes required. The specified IDRCFACTOR is used to determine the effective capacity of the target device type. Because GFTAVMA cannot recognize data sets that have been software compacted, GFTAVMA does not account for software compaction when calculating the effective device capacity.

 6  An asterisk (*) in the # CURRENT STAT-VOLS column shows that the volume has been reused. If the volumes associated with a data set no longer exist, there is an '*' following the current statistical volumes value. In this case, the current value for statistical volumes is the original number of statistical volumes associated with the data set.

GFTAVMA does not count a volume more than once. To avoid double counting, the reused volumes are not accumulated in the totals for the IDRC Report. Therefore, the columns for current ( 6 ) and projected ( 7 ) statistical volumes do not add up to their totals.

 7  The projected numbers of statistical volumes and statistical mounts result from the combination of the IDRCFACTOR, TAPEDEV, and TAPELEN keywords. An asterisk (*) in the 3490E STAT-VOLS column shows that the volume has been reused.