What's Batch Control Logic?

Batch control logic is used to define the logic by which numeric fields in one file are to be accumulated into fields in another file.

E.g.
FILE A FILE B
Empno Empno
Annual Salary year
Year month
Salary

Keyfield Keyfield
Empno Empno
Year year

Batch control logic can be applied so that the annual salary for the year for the empno in FILEA is obtained by totaling the salary for the same empno & year in FILE B