If the number of buffers indicated in the QSAM DCBBUFNO field for certain DASD or tape data sets is zero when IFG0EX0B gets control, the BUFNO subroutine defaults the number of buffers. The block size in the DCB (DCBBLKSI) is used, together with a fixed amount of storage (64 KB in the example) to determine a buffer number. The buffer number is limited to a fixed value (32 in the example). Storage quantity and maximum buffer number are contained in two tables, DAMAX and TPMAX, that are used for DASD devices and tape devices, respectively. Storage quantity is expressed in units of 1024 (1 KB) bytes. You can use IFG0EX0B to alter the values in the DAMAX and TPMAX tables.