The PROCESS(UNDEFINEDSORG) keyword permits logical data set restore of an undefined DSORG data set to an unlike device of larger track capacity. The restore yields a usable data set; however, some unused space might remain on each track of the target data set. It may not always be possible to restore all undefined DSORG data sets to an unlike device type, even when the unlike device type has a track capacity greater than or equal to the source device. For example, if the source device is a 3380, the output device is a 3390, and the data set’s block size is less than 277 bytes, a track on the target cannot contain as much data as a track on the source, and message ADR366W (invalid track format) is issued.