HLASM Language Reference

Relationship of Assembler to Operating System
Relationship of Assembler to Operating System
High Level Assembler operates under the OS/390 operating system, the MVS/ESA
operating system, the CMS component of the VM/ESA® operating system, and the
VSE/ESA operating system. 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.
MVS: MVS 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 or binder
– Loader
CMS: 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
VSE: 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:
8 HLASM V1R5 Language Reference