IPO - Initial Program Offering

Enhanced Definition

In the context of IBM mainframe systems, an Initial Program Offering (IPO) refers to the initial, uncustomized version of an IBM software product (such as z/OS, CICS, DB2, or IMS) as delivered by IBM. It represents the base installation package that customers receive before any site-specific customization or configuration is applied. The IPO serves as the foundational, "vanilla" instance from which a fully configured system is built.

Key Characteristics

- Uncustomized Base: An IPO contains only IBM-supplied defaults and no customer-specific modifications, representing the product in its pristine, out-of-the-box state.
- Installation Foundation: It is the starting point for installing a new IBM software product or a major new release of an existing product onto a z/OS system.
- SMP/E Driven: The installation process for an IPO is primarily managed by SMP/E (System Modification Program/Extended), IBM's standard tool for installing and maintaining z/OS software.
- Target and Distribution Libraries: An IPO consists of various data sets (libraries) that are loaded into specific Target Libraries (TLIBs) and Distribution Libraries (DLIBs) on the customer's system.
- Extensive Documentation: It is accompanied by comprehensive IBM documentation, including installation guides, customization manuals, and product reference materials.
- System Programmer Responsibility: Installing and customizing an IPO requires significant expertise from system programmers to integrate it into the existing mainframe environment.

Use Cases

- New Product Deployment: Installing a completely new IBM software product (e.g., a new version of CICS Transaction Server) onto a z/OS system for the first time.
- Major Release Upgrade: Performing an upgrade to a new major release of an existing product (e.g., moving from z/OS V2.4 to z/OS V2.5), which often involves installing the new release's IPO.
- Disaster Recovery Baseline: Maintaining a clean, uncustomized IPO as a known good baseline for disaster recovery planning, allowing for rapid re-installation in critical situations.
- Test Environment Setup: Creating a fresh, isolated test environment to evaluate new features or functionalities of an IBM product before applying any site-specific customizations.

Related Concepts

An IPO is the fundamental input for SMP/E, which then manages the installation, maintenance, and tracking of all software changes on z/OS. Once an IPO is installed, it forms the base upon which APARs (Authorized Program Analysis Reports) and PTFs (Program Temporary Fixes) are applied to address defects or introduce minor enhancements. It is the initial step in a system programmer's journey to customize and integrate IBM products into the broader z/OS operating environment, often involving extensive use of JCL for installation jobs and ISPF for configuration.

Best Practices:

Dedicated SMP/E Zones: Always install IPOs into dedicated SMP/E Global, Target, and Distribution Zones to ensure clear separation from other software and simplify future maintenance.
Thorough Documentation Review: Carefully read and understand all IBM-supplied installation and customization guides before initiating the IPO installation process.
Staging Environment First: Perform initial IPO installations and customizations in a non-production (e.g., development or test) environment to validate the process and configuration before deploying to production.
Backup Before Customization: Create comprehensive backups of the newly installed IPO libraries immediately after installation and before applying any site-specific customizations.
Version Control for Customizations: Implement a robust change management system to track and manage all site-specific modifications made to the IPO, ensuring reproducibility and easier upgrades.