The BLOCK CONTAINS clause is syntax checked but has no effect on the execution of the program.
If only integer-2 is specified, it specifies the exact number of bytes in the physical record. When integer-1 and integer-2 are both specified, they represent the minimum and maximum number of bytes in the physical record, respectively.
integer-1 and integer-2 must include any control bytes and padding contained in the physical record. (Logical records do not include padding.)
The CHARACTERS phrase is the default. CHARACTERS must be specified when:
The compiler assumes that the block size must provide for integer-2 records of maximum size, and provides any additional space needed for control bytes.