Relationship of assembler to operating system

High Level Assembler operates under the z/OS operating system, the CMS component of the z/VM operating system, the z/VSE operating system, and Linux for System z®. These operating systems provide the assembler with services for:

Assembling a source module
Running the assembled object module as a program

In writing a source module, you must include instructions that request any required service functions from the operating system.

z/OS provides the following services:

For assembling the source module:
- A control program
- Sequential data sets to contain source code
- Libraries to contain source code and macro definitions
- Utilities
For preparing for the execution of the assembler program as represented by the object module:
- A control program
- Storage allocation
- Input and output facilities
- Binder
- Loader

CMS provides the following services:

For assembling the source module:
- An interactive control program
- Files to contain source code
- Libraries to contain source code and macro definitions
- Utilities
For preparing for the execution of the assembler program as represented by the object modules:
- An interactive control program
- Storage allocation
- Input and output facilities
- Linker
- A loader

z/VSE provides the following services:

For assembling the source module:
- A control program
- Sequential data sets to contain source code
- Libraries to contain source code and macro definitions
- Utilities
For preparing for the execution of the assembler program as represented by the object module:
- A control program
- Storage allocation
- Input and output facilities
- Linker

Linux for System z provides the following services:

For assembling the source module:
- An interactive control program
- Files to contain source code
- Utilities
For preparing for the execution of the assembler program as represented by the object modules:
- An interactive control program
- Storage allocation
- Input and output facilities
- Linker
- A loader