Under OPTION(*BLK), the BLOCK CONTAINS clause causes the compiler to generate
code that blocks output records and unblocks input records if the following
conditions are satisfied:
- The file access is dynamic.
- The organization of the file is indexed and the file is open only for
input or output.
- The file is assigned to DISK or DATABASE.
If the BLOCK CONTAINS clause specifies a record size of zero, the system
default blocking factor applies.