z390 - Mainframe Assembler and Emulator toolkit

Develop, test, and deploy mainframe assembler and COBOL programs on your PC

• IBM® HLASM compatible macro assembler
  • Common z/OS® and z/VSE® compatible macros
  • Structured programming macros compatible with IBM HLASM Toolkit
• IBM Enterprise COBOL compatible compiler
• QSAM/VSAM compatible file processing
• TN3270 compatible data streams
• CICS® compatible transaction processor
• GPLv2 licensed

Ideal for a number of use cases:

• Learning IBM mainframe assembler programming without access to a mainframe.
• Develop your mainframe application using modern tooling.

Get started

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