PARMLIB
The library of members that holds z/OS's own settings, read when the system starts and on some commands.
Also written SYS1.PARMLIB, parmlib member, IEASYS, PROGxx
PARMLIB is where z/OS keeps its configuration. It is a partitioned dataset, usually SYS1.PARMLIB plus a few site libraries searched in order, and each member controls one area of the system.
Member names have a fixed stem and a two-character suffix. IEASYSxx holds the main system settings. SMFPRMxx controls SMF recording. PROGxx lists authorised program libraries. BPXPRMxx sets up Unix System Services. The suffix lets a site keep several versions side by side, such as IEASYS00 and IEASYS01, and choose between them.
Most members are read at IPL. Many can also be reloaded while the system runs, with a SET command, so a change does not always need a restart.
Because a mistake in PARMLIB can stop a system from starting, changes go through change control and are normally made by system programmers. As a learner, it is worth knowing it exists: when someone asks "where is that set?", the answer is often a PARMLIB member.
Where can I learn this hands-on?
Right here, at ZedBank. You take a junior job at a simulated bank and learn each part of the work by doing it, with Zed beside you. There's nothing to install.
Start at ZedBankRelated
- IPLInitial program load: starting z/OS on a system, the mainframe word for booting.
- z/OSThe main operating system that runs on IBM mainframes, in the same way Windows or Linux runs on a laptop or server.
- System programmerThe person who installs, configures, tunes and upgrades the operating system and its subsystems.
- SMFSystem Management Facilities: the z/OS feature that writes a detailed record of what happened on the system, used for billing, performance and security.
- Change controlThe process every change goes through before reaching production: reviewed, approved, scheduled and reversible.
- Partitioned datasetA dataset that works like a library or folder, holding many separately named members inside one dataset.