COBOL (Common Business-Oriented Language) and JCL (Job control language) are a double edge tool for fine tuning and executing tasks on Mainframes.
Common Business-Oriented Language (COBOL) is a compiled English-like computer programming language designed for business use. It is imperative, procedural and, since 2002, object-oriented. It is primarily used in business, finance, and administrative systems for companies and governments. It is still widely used in legacy applications deployed on mainframe computers, such as large-scale batch and transaction processing jobs.
Job Control Language (JCL) is the command language of the Mainframe. It identifies the program to be executed, the inputs that are required and location of the input/output and informs the Operating System through Job control statements. In short, you use JCL to execute your COBOL program.