OS 2200

Unisys OS 2200 operating system

OS 2200 is the operating system currently used for the Unisys ClearPath Dorado family of mainframe systems. OS 2200 is a lineal descendant of Exec 8 for the UNIVAC 1108. The name Exec 8 was shorthand for “Executive System for the UNIVAC 1108.” The UNIVAC 1108 computer was announced in 1964 and...

 has had several generations of compilers and linkers in its history supporting a wide variety of programming language

Programming language

A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

s. In the first releases, the Exec II assembler (SLEUTH) and compilers were used. The assembler was quickly replaced with an updated version (ASM) designed specifically for the 1108 computer and Exec 8 but the early compilers continued in use for quite some time.

Universal Compiling System

The modern compiling system for OS 2200 is known as UCS, Universal Compiling System. The UCS architecture uses a common syntax analyzer, separate semantic front ends for each language and a common back-end and optimizer. There is also a common language runtime environment. The UCS system was developed starting in 1969 and initially included PL/I

PL/I

PL/I is a procedural, imperative computer programming language designed for scientific, engineering, business and systems programming applications...

 and Pascal

Pascal (programming language)

Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...

. FORTRAN

Fortran

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

 and COBOL were soon added. Ada

Ada (programming language)

Ada is a structured, statically typed, imperative, wide-spectrum, and object-oriented high-level computer programming language, extended from Pascal and other languages...

 was added later. The currently supported languages include COBOL, FORTRAN, C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

, and PLUS. PLUS, Programming Language for Unisys (originally UNIVAC) Systems, is a block structured language somewhat similar to Pascal which it predates.

Legacy Compilers

Previous PLUS, COBOL and FORTRAN compilers are also still supported. An even earlier FORTRAN compiler (FORTRAN V), while no longer supported, is still in use for an application developed in the 1960s in that language.

Compilers previously existed for Algol, Simula

Simula

Simula is a name for two programming languages, Simula I and Simula 67, developed in the 1960s at the Norwegian Computing Center in Oslo, by Ole-Johan Dahl and Kristen Nygaard...

, BASIC

BASIC

BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....

, Lisp, NELIAC

NELIAC

The Navy Electronics Laboratory International ALGOL Compiler or NELIAC is a dialect and compiler implementation of the ALGOL 58 programming language developed by the Naval Electronics Laboratory in 1958....

, JOVIAL

JOVIAL

JOVIAL is a high-order computer programming language similar to ALGOL, but specialized for the development of embedded systems .JOVIAL is an acronym for "Jules Own Version of the International...

, and other programming languages that are no longer in use on the ClearPath OS 2200 systems.

Assembler

The assembler, MASM, is heavily used both to obtain the ultimate in efficiency and to implement system calls that are not native to the programming language. Much of the MASM code in current use is a carryover from earlier days when compiler technology was not as advanced and when the machines were much slower and more constrained by memory size than today.

Linking

There are two linking systems used. The collector (@MAP) combines the output relocatable elements of the basic-mode compilaters and assemblers into an absolute element which is directly executable. While this linker is intended primarily to support basic mode, the relocatable and absolute elements may contain extended-mode as well. This is often the case when an existing application is enhanced to use extended mode or call extended mode libraries but still contains some basic mode code. The Exec is an example of such a program.

The linker (@LINK) is the modern linking environment which combines object modules into a new object module. It provides both static and dynamic linking capabilities. The most common usage is to combine the object modules of a program statically but to allow dynamic linking to libraries.

Java

OS 2200 provides a complete Java

Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

 environment optimized for the 2200 Series architecture.
Java on OS 2200 has evolved from an interesting additional capability for small servlets and tools to a full environment capable of handling large applications. The Unisys Java Virtual Machine is fully compliant with and passes the Sun

Sun Microsystems

Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

 certification suite. The environment includes a full J2EE

Java Platform, Enterprise Edition

Java Platform, Enterprise Edition or Java EE is widely used platform for server programming in the Java programming language. The Java platform differs from the Java Standard Edition Platform in that it adds libraries which provide functionality to deploy fault-tolerant, distributed, multi-tier...

^tm application server environment using the Tomcat

Apache Tomcat

Apache Tomcat is an open source web server and servlet container developed by the Apache Software Foundation...

 open source web server from the Apache Software Foundation

Apache Software Foundation

The Apache Software Foundation is a non-profit corporation to support Apache software projects, including the Apache HTTP Server. The ASF was formed from the Apache Group and incorporated in Delaware, U.S., in June 1999.The Apache Software Foundation is a decentralized community of developers...

 and the JBoss application server. All of this has been integrated with the OS 2200 security, databases, and recovery environment.