DPPX
Encyclopedia
Distributed Processing Programming Executive was an operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 introduced by IBM, pre-installed on selected computer models in the 1980s.

Brief history

  • It was first introduced on the IBM 8100
    IBM 8100
    See also: IBM 8000 series, canceled in 1961The IBM 8100 was at one time IBM’s principal distributed processing engine, providing local processing capability under two incompatible operating systems and was follow-on to IBM 3790....

     model, which was released in 1978. It is also adopted as the operating system for its successor model, the IBM 8150 in 1983.
  • 1987 saw the release of Distributed Processing Programming Executive System Product (DPPX/SP) Release 4.
  • In 1986, IBM
    IBM
    International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

     decided to cease the IBM 8100 architecture to consolidate its hardware and software families.
  • In 1988, they released DPPX/370 which ran on the ES/9370 processors (an S/370 model).
  • By the end of June 1997, DPPX/370 was officially retired.

Architecture

DPPX was written in Programming Language for Distributed Systems (PL/DS), a PL/I
PL/I
PL/I is a procedural, imperative computer programming language designed for scientific, engineering, business and systems programming applications...

-derived systems programming language, similar to the PL/S systems programming language used for MVS
MVS
Multiple Virtual Storage, more commonly called MVS, was the most commonly used operating system on the System/370 and System/390 IBM mainframe computers...

 and VM
VM
VM may stand for:In business*VM Motori, a diesel engine manufacturer*Vauxhall Motors, a British car maker*Viaggio Air *Virgin Media, a cable provider in the United Kingdom*Virgin Mobile, a mobile phone service...

. Part of the DPPX/370 development process was developing a PL/DS 2 language, which was based on PL/DS, but with changes necessitated by the changed instruction set. (PL/DS, like PL/S, is a high-level language which encourages significant use of inline assembly.)

The user interfaces (e.g., command line) of DPPX were very clean and easy to use, the syntax of the commands, the whole concept and ideas of DPPX looked very straightforward and consistent (command line, online help, etc.), and each and every aspect was documented online and in a rich set of well organized printed manuals. A DPPX system could be operated truly operator-less and remote (hence the Distributed part of the name). One benefit of this clean design was that programs could be written in modern dialects of COBOL
COBOL
COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....

, and dialogs could be developed interactively.

Software

In addition to the expected functions of an operating system, DPPX included several functions which allowed for remote administration, such as Distributed Host Command Facility (DHCF), which allowed a Host Command Facility (HCF) user on a mainframe to log on in either full-screen mode or line mode to execute commands as though logged on locally, and Distributed Systems Network (or Node) Executive (DSNX), which allowed a Distributed Systems Executive (DSX) (later NetView/DM) job to manage files.

Separate additional products were also available, including COBOL
COBOL
COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....

 and Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...

compilers, the Distributed Transaction Management System (DTMS), Command Facilities Extensions (CFE), which provided easy support for full-screen applications, Data Stream Capability (DSC) to allow DPPX users to log on to applications on the mainframe, and Performance Tool (PT).
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