System tailoring is the overall process by which an installation
selects its operating system. The process consists of the specification
of system options through these mechanisms:
- MVS™ hardware configuration
definition (HCD), which is described in MVS hardware configuration definition.
- Initialization-time selections which appear in the topic System tailoring at initialization time.
- Implicit system parameters which appear in the topic Implicit system parameters.
- After IPL, system tailoring through operator commands. One example
of a command that will perform a system tailoring function is the
SETPROG command (for example, SETPROG LPA,ADD). You get the same result
whether you activate a function by issuing a SETPROG command or by
activating the PROGxx parmlib member.
For more information about
how to use commands to start, load, initialize, and control your system,
see z/OS MVS System Commands.
Note: Many system options have defaults. The IBM® defaults for some of these options might
change in a future release. If you want to continue using the current
default, set the default value that you want.
An installation can identify one or more active instances of the
operating system. For example, the installation might choose to identify
a specific instance to be used only during off-shift hours.
To identify an instance of the operating system, the installation
assigns a unique 16-character EBCDIC identifier by using the AMASPZAP
program immediately after system initialization, or by creating an
alternate nucleus. For more information about AMASPZAP, see z/OS MVS Diagnosis: Tools and Service Aids.
For more information
about creating an alternate nucleus, see Specifying an alternate nucleus.