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Control Program Facility

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Control Program Facility (CPF) was the operating system for the IBM System/38. CPF is not related to SSP.

Overview

The System/38's advanced operating system lives on with IBM's AS/400. Realising the importance of the thousands of lines of 'legacy code' (programs) written, 'AS' stands for 'Application System'. Great efforts were made by IBM to enable programs originally written for the System/34 and /36 to be moved to the AS/400.

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 architecture, where main storage and disk storage are organized as one, from the abandoned IBM Future Systems project (FS).[1] 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

System/38 was one of the few commercial[citation needed] computers with capability-based addressing. (The earlier Plessey 250 was one of the few other computers with capability architecture ever sold commercially.) Capability-based addressing was removed in the follow-on AS/400 and iSeries models.[2] Capability-based operating system refers to an operating system that uses capability-based security.

References

  1. ^ Mark Smotherman. "IBM Future System (FS) - 1970s". Retrieved October 11, 2017.
  2. ^ Soltis, Frank G. (July 2001). Fortress Rochester: The Inside Story of the IBM ISeries. 29th Street Press. p. 119. ISBN 978-1-58304-083-6..
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