Number of records = 100000, RECFM=FB, LRECL=125
Blocksize = INTEGER(27998 / LRECL) - Although specifying only RECFM and LRECL will invoke system determined blocksize.
Records per block = Blocksize / LRECL
Records per track = Records per block * 2
Records per cylinder = Records per track * 15
For VB records it is safest to use the maximum LRECL to determine the space requirements, but always use 27998 as blocksize.