To determine the number of equal-length records that can be written on a track, code TRKCALC with FUNCTN=TRKCAP. You must specify the number of existing records on the track and the key and data length of the new records (using either the R, K, and DD keywords or the R, K, and DD bytes in the RKDD parameter).

If you wish to regard the track as being empty, specify an R value of 1. Otherwise, specify an R value that is one greater than the number of existing records on the track.

If the length of any existing record differs from the length of the new records (as specified in the DD value), then code the BALANCE parameter. Otherwise, omit the BALANCE parameter.