For compiler data sets other than the work data sets (SYSUTn) and HFS files, you can set the block size by using the BLKSIZE subparameter of the DCB parameter. The value must be permissible for the device on which the data set resides. The values you set depend on whether the data sets are fixed length or variable length.
For fixed-length records (RECFM=F or RECFM=FB), LRECL is the logical record length; and BLKSIZE equals LRECL multiplied by n where n is equal to the blocking factor.
The following table shows the defined values for the fixed-length data sets. In general, you should not change these values, but you can change the value for the following data sets:
| Data set | RECFM | LRECL (bytes) | BLKSIZE1 |
|---|---|---|---|
| SYSDEBUG2 | F or FB | 80 to 10243 | LRECL x n |
| SYSIN | F or FB | 80 | 80 x n |
| SYSLIB or other copy libraries | F or FB | 80 | 80 x n |
| SYSLIN | F or FB | 80 | 80 x n |
| SYSMDECK | F or FB | 80 | 80 x n |
| SYSOPTF | F or FB | 80 | 80 x n |
| SYSPRINT2 | F or FB | 133 | 133 x n |
| SYSPUNCH | F or FB | 80 | 80 x n |
| SYSTERM | F or FB | 80 | 80 x n |
|
|||
For variable-length records (RECFM=V), LRECL is the logical record length, and BLKSIZE equals LRECL plus 4.