BLKSIZE specification - Key = '0030'

DALBLKSZ specifies the block size. It is mutually exclusive with the buffer size key (DALBUFSZ). When you code DALBLKSZ, # must be one, LEN must be two or eight, and PARM contains the block size. The maximum PARM value is '7FF8' (32,760) for DASD and '80000000' (2,147,483,648) for tape. A LEN value of eight must be used for block size specifications greater than '7FF8'. You may also code one of the block size type keys (DALKILO, DALMEG or DALGIG) when you specify DALBLKSZ. If you do not specify one of those keys, the value coded on DALBLKSZ is considered to be in bytes.

KEY    #      LEN    PARM
0030   0001   0002   00 50

KEY    #      LEN    PARM
0030   0001   0008   00 00 00 00 00 00 00 50