Control Program Facility
| Company type | Operating system |
|---|---|
| Industry | Computer software |
| Founded | 1978 |
| Headquarters | United States |
| Products | Operating system for IBM System/38 |
Control Program Facility (CPF) serves as the operating system for the IBM System/38. Developed independently at IBM Rochester, CPF differs from the earlier System Support Program OS. It later progressed into the OS/400 operating system, initially referred to as XPF (Extended CPF).
While CPF is acknowledged as the core OS of the System/38, crucial hardware and resource management responsibilities are executed by the System/38's Horizontal and Vertical Microcode layers.
Overview of libraries
- QGPL – library for general purposes
- QSYS – core system library
- QSPL – library dedicated to spooling
- QTEMP – temporary storage library
- QSRV – library for system services
- QRECOVERY – library focused on system recovery
Storage architecture
Contrary to most earlier computer systems that stored data in distinct logical files with physical sector assignments, the System/38 adopted a single-level store model derived from the IBM Future Systems project. This design merges primary memory and disk storage into one unified address space, enabling management of all data elements without needing physically contiguous files, thereby improving storage flexibility and simplifying system oversight.
Capability-based addressing
CPF was one of the rare commercial operating systems to implement capability-based addressing, a security framework that governs access rights via capabilities. This sophisticated addressing mechanism was exclusive to System/38 but was discontinued in its follow-up, OS/400.
Distributed Data Management
In 1986, System/38 incorporated support for the Distributed Data Management Architecture (DDM), middleware designed to allow transparent sharing and retrieval of record-oriented files among remote System/36, System/38, and IBM mainframe systems running CICS. This feature enabled cohesive data management across distributed IBM platforms.
Supported programming languages
The System/38 environment accommodated essential business programming languages such as RPG III, COBOL, BASIC, and PL/I. Additionally, it utilized the System/38-specific Control Language (CL) for managing system tasks and automation.