Free tools Windows power users keep installed
One-click scans. No signup required.
An initial program load (IPL) is the startup procedure that loads an operating system into memory and begins running it. In IBM’s z/OS terminology, IPL loads system programs from disk into the processor’s real storage and executes them, beginning operating-system initialization.
What happens during a z/OS IPL?
IBM describes the z/OS IPL as more than copying program code into memory: it starts a sequence that prepares the operating system to do work.
As an Amazon Associate I earn from qualifying purchases.
- Load and execute system programs: A copy of the operating system is loaded from disk into real storage and executed.
- Initialize the system and storage: z/OS performs system and storage initialization, including creating system component address spaces.
- Start system management and subsystems: The master scheduler and subsystems are initialized so the system can provide its services.
These are high-level stages, not a universal IPL recipe; the detailed procedure depends on the system and its configuration. IBM’s z/OS IPL documentation describes the sequence.
Is IPL the same as booting?
For z/OS, IBM’s glossary lists “boot” and “load” as synonyms for initial program load. In everyday computer terminology, booting likewise means starting an operating system. The terms describe the same broad purpose, but the mechanics vary by platform; an IPL should not be taken to mean that every operating system starts in the same way. IBM’s z/OS glossary defines IPL as the initialization procedure that causes z/OS to begin operation.
#1 Best Overall
- Learn the essential concepts and tools required to work with IBM i systems
- Understand traditional methods of working with the system as well as newer methods such as SQL
- Update your skill set by learning how to use IBM's latest graphical tools and methods
- Gain a solid foundation for more advanced programming studies such as CL and RPG
Where else is the term used?
IBM i
IBM i documentation also calls its startup sequence an IPL. System programs load from a designated source device, and the system hardware is checked. That is a platform-specific description, not a claim that IBM i and z/OS use identical startup steps. IBM’s IBM i 7.6 documentation explains its startup process.
LPAR load commands
In Broadcom’s LPAR reference, LOAD and IPL are synonymous commands. The reference distinguishes CCW-based load operations from list-directed SCSI load operations, illustrating that the command and loading method depend on the environment. Broadcom’s LOAD (IPL) reference covers those command options.
Quick Recap
Best Value
Rank #3
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
