The Common Business Oriented Language (COBOL) computer programming language is over 60 years old. Some consider it to be outdated, and those that program in it have been jokingly called dinosaurs. However, COBOL is still widely in use in banks, insurance companies, governments, and other financial institutions to efficiently and securely process large amounts of data through computer programs run on Mainframes. There are basically 2 different forms of COBOL program processing: Batch and Online.
Batch Processing
Batch COBOL programs are scheduled through Job Control Language (JCL) jobs to be run at a specific time, in a certain order. For example, data may be batched in files and processed overnight to update a DB2 database. JCL jobs are set to specify who has access to run the program as well as time parameters. The input data file names are also included in the JCL job, along with the COBOL program name and an output location.
Online Processing
There are CICS (Customer Information Control System) programs that are online COBOL programs containing CICS commands. They are run in real-time for screen display and data capture. For instance, while programs run in the background, screens are displayed to a user to allow data entry. The data captured is processed and saved, possibly to a DB2 database.
Coding Environment
The COBOL coding environment is typically an interactive TSO (Time Sharing Option) session on a Mainframe computer. If you would like more details, IBM has a What is TSO section on their website. Most users work with TSO through its menu-driven interface, Interactive System Productivity Facility (ISPF). What is ISPF is also available through the IBM website.
In summary, COBOL programs are compiled and run in a Mainframe TSO environment, using an ISPF interface. These programs can be set to run on a schedule in a JCL job, using batch processing; or through an online environment, using CICS.
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