Control Program Facility (CPF) is the

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

of the

IBM System/38 The System/38 is a discontinued minicomputer and midrange computer manufactured and sold by IBM. The system was announced in 1978. The System/38 has 48-bit addressing, which was unique for the time, and a novel integrated database system. It w ...

. CPF represented an independendent line of development at

IBM Rochester IBM Rochester is the facility of IBM in Rochester, Minnesota. The initial structure was designed by Eero Saarinen, who clad the structure in blue panels of varying hues after being inspired by the Minnesota sky, as well as IBM's nickname of " Big ...

, and was unrelated to the earlier and more widely used

System Support Program ''System Support Program (SSP)'' was the operating system of the IBM System/34 and System/36 minicomputers. SSP was a command-based operating system released in 1977. ''SSP'' originally contained 60 or so commands that were implemented on the Sy ...

operating system. CPF evolved into the

OS/400 IBM i (the ''i'' standing for ''integrated'') is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS ...

operating system, which was originally known as XPF (Extended CPF). While CPF is considered to be the operating system of the System/38, much of the hardware and resource management of the platform is implemented in the System/38's Horizontal and Vertical Microcode.

Description of the libraries

* QGPL – general purpose library * QSYS – system library * QSPL – spooling library * QTEMP – temporary library * QSRV – system service library * QRECOVERY – system recovery library

Data storage

In most computers prior to the System/38, and most modern ones, data stored on disk was stored in separate logical files. When data was added to a file it was written in the sector dedicated to this, or if the sector was full, on a new sector somewhere else. The System/38 adopted the

single-level store Single-level storage (SLS) or single-level memory is a computer storage term which has had two meanings. The two meanings are related in that in both, pages of memory may be in primary storage (RAM) or in secondary storage (disk), and that the p ...

architecture, where main storage and disk storage are organized as one, from the abandoned

IBM Future Systems project The Future Systems project (FS) was a research and development project undertaken in IBM in the early 1970s, aiming to develop a revolutionary line of computer products, including new software models which would simplify software development by ex ...

(FS). Every piece of data was stored separately and could be put anywhere on the system. There was no such thing as a physically contiguous file on disk, and the operating system managed the storage and recall of all data elements.

Capability-based addressing

CPF was an example of a commercially-available

Capability-based operating system Capability-based operating system generally refers to an operating system that uses capability-based security. Examples include: * Hydra *KeyKOS *EROS *CapROS *Midori *seL4 * Genode *Fuchsia *Control Program Facility Control Program Facility (CP ...

. System/38 was one of the few commercial computers with

capability-based addressing In computer science, capability-based addressing is a scheme used by some computers to control access to memory as an efficient implementation of capability-based security. Under a capability-based addressing scheme, pointers are replaced by protec ...

. Capability-based addressing was removed in the follow-on

operating system..

Distributed Data Management

In 1986, System/38 announced support for

Distributed Data Management Architecture Distributed Data Management Architecture (DDM) is IBM's open, published software architecture for creating, managing and accessing data on a remote computer. DDM was initially designed to support record-oriented files; it was extended to support ...

(DDM). Such a

middleware Middleware is a type of computer software that provides services to software applications beyond those available from the operating system. It can be described as "software glue". Middleware makes it easier for software developers to implement co ...

in the context of a distributed system is the software layer that lies between the operating system and applications. Distributed Data Management Architecture defines an environment for sharing data. This enables System/38 programs to create, manage, and access record-oriented files on remote System/36, System/38, and IBM mainframe systems running CICS. It also allows programs on remote System/36 and System/38 computers to create, manage, and access files of a System/38.

Programming languages

Languages supported on the System/38 included RPG III,

COBOL COBOL (; an acronym for "common business-oriented language") is a compiled English-like computer programming language designed for business use. It is an imperative, procedural and, since 2002, object-oriented language. COBOL is primarily us ...

BASIC BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...

, and

PL/I PL/I (Programming Language One, pronounced and sometimes written PL/1) is a procedural, imperative computer programming language developed and published by IBM. It is designed for scientific, engineering, business and system programming. I ...

. CPF also implements the

Control Language The Control Language (CL) is a scripting language originally created by IBM for the System/38 Control Program Facility and later used in OS/400 (now known as IBM i). It bears a resemblance to the IBM Job Control Language and consists of a set of ...

for System/38.

References

External links

Control Program Facility Concepts Manual
(PDF file)
Control Program Facility Programmer's Guide
(PDF file) {{IBM operating systems IBM operating systems Computer-related introductions in 1978