Introduction to z/OS UNIX

The UNIX System Services element of z/OS® is a UNIX operating environment, implemented within the z/OS operating system. It is also known as z/OS UNIX. The z/OS support enables two open systems interfaces on the z/OS operating system: an application programming interface (API) and an interactive shell interface.

Many users use similar interfaces on other systems and use terminology different from z/OS terminology. For example, they call virtual storage memory. The work done by their system administrators is handled by system programmers in z/OS systems. Where possible, individual terms and phrases are indicated.

To sum up z/OS UNIX:

z/OS UNIX System Services (a component of the BCP FMID) provides:
- XPG4 UNIX 1995 conformance
- Assembler callable services
- TSO/E commands to manage the file system
- ISPF shell environment
z/OS UNIX System Services Application Services (FMID HOTxxxx) interprets commands from users or from programs, called shell scripts, and requests MVS™ services in response to the commands. It provides:
- A TSO/E command to enter the shell environment
- A shell environment for developing and running applications
- Utilities to administer and develop in a UNIX environment
- Support for socket applications
- Remote login (rlogin) and inetd functions
- Direct telnet based on TCP/IP protocol
- A dbx debugger to enable the application programmer to debug source programs written in C or C/C++.
- Support for full-screen applications (curses support)
- The ability to run programs interactively in the foreground, or in the background