# Job Control Language

> scripting languages used on IBM mainframe operating systems to instruct the system on how to run a batch job or start a subsystem

**Wikidata**: [Q1505372](https://www.wikidata.org/wiki/Q1505372)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Job_Control_Language)  
**Source**: https://4ort.xyz/entity/job-control-language

## Summary
Job Control Language (JCL) is a scripting language used on IBM mainframe operating systems to instruct the system on how to run batch jobs or start subsystems. It is a specialized programming language designed for automating tasks in mainframe environments, ensuring efficient execution of batch processes and subsystem initialization.

## Key Facts
- **Instance of**: Programming language
- **Aliases**: JCL, Lenguaje de Control de Trabajos, ジョブ制御言語
- **Used for**: Running batch jobs and starting subsystems on IBM mainframes
- **File formats**: JCL script (with rem) for both readable and writable files
- **Wikipedia presence**: Available in 10 languages (az, ca, cs, da, de, en, es, fr, it, ja)
- **Library of Congress ID**: sh85070574
- **National Library of Israel ID**: 987007533717305171
- **Wikidata description**: Scripting languages used on IBM mainframe operating systems to instruct the system on how to run a batch job or start a subsystem

## FAQs
### Q: What is Job Control Language used for?
A: Job Control Language (JCL) is used to instruct IBM mainframe operating systems on how to run batch jobs or start subsystems. It automates tasks in mainframe environments, ensuring efficient execution of batch processes.

### Q: Is JCL still used today?
A: While JCL is primarily associated with IBM mainframes, it remains relevant in legacy systems and some modern mainframe environments. Its use depends on the specific needs of the organization and the continued support for mainframe systems.

### Q: How does JCL differ from other scripting languages?
A: JCL is specifically designed for IBM mainframe operating systems and is optimized for batch job execution and subsystem management. Unlike general-purpose scripting languages, JCL focuses on automating tasks in mainframe environments.

### Q: Can JCL scripts be modified or created manually?
A: Yes, JCL scripts can be created and modified manually using a text editor. They are typically saved with a `.jcl` file extension and can include comments marked with `//*`.

### Q: Where can I find more information about JCL?
A: Detailed information about JCL can be found on Wikipedia in multiple languages, including English, Spanish, and Japanese. Additionally, IBM documentation and mainframe user communities often provide further insights.

## Why It Matters
Job Control Language (JCL) plays a crucial role in the operation of IBM mainframe systems, particularly in environments where batch processing is essential. It allows system administrators and developers to automate repetitive tasks, ensuring efficient execution of batch jobs and subsystem initialization. JCL’s specialized design makes it indispensable for maintaining and managing mainframe environments, where reliability and performance are critical. While newer technologies have emerged, JCL remains a foundational tool in legacy systems and continues to be relevant in industries that rely on mainframe infrastructure. Its ability to streamline batch processing and subsystem management underscores its significance in the field of mainframe computing.

## Notable For
- **Specialized scripting language**: Designed exclusively for IBM mainframe operating systems, focusing on batch job execution and subsystem management.
- **Legacy relevance**: Continues to be used in legacy mainframe environments, demonstrating its enduring utility in certain industries.
- **Automation of tasks**: Enables efficient automation of repetitive tasks, reducing manual intervention and improving system performance.
- **Integration with mainframe systems**: Seamlessly integrates with IBM mainframe operating systems, ensuring compatibility and reliability.
- **Widespread documentation**: Available in multiple languages on Wikipedia, reflecting its broad adoption and importance in mainframe computing.

## Body
### Overview
Job Control Language (JCL) is a scripting language used on IBM mainframe operating systems to automate the execution of batch jobs and the initialization of subsystems. It is a specialized programming language designed to communicate instructions to the mainframe, ensuring efficient and reliable operation in batch processing environments.

### Usage and Applications
JCL is primarily used for:
- **Batch job execution**: Automating the processing of large volumes of data in a sequential manner.
- **Subsystem management**: Starting and managing subsystems within the mainframe environment.
- **Task automation**: Reducing manual intervention by scripting repetitive tasks.

### File Formats and Syntax
JCL scripts are typically saved with a `.jcl` file extension and can include comments marked with `//*`. The language uses a structured syntax to define job steps, resource allocation, and execution parameters.

### Historical Context
JCL was developed as part of IBM’s mainframe operating systems, reflecting the need for a specialized scripting language to manage batch processing and subsystem operations. Its design aligns with the requirements of mainframe environments, where reliability and performance are paramount.

### Documentation and Resources
Detailed information about JCL can be found on Wikipedia in multiple languages, including English, Spanish, and Japanese. Additionally, IBM documentation and mainframe user communities provide further insights into its usage and best practices.

## References

1. [Source](https://github.com/JohnMarkOckerbloom/ftl/blob/master/data/wikimap)
2. Freebase Data Dumps. 2013
3. Quora
4. National Library of Israel Names and Subjects Authority File