LINC 4GL
Encyclopedia
LINC is a fourth-generation programming language
, used mostly on Unisys
computer systems.
That is, these businesses dealt with "commodities", or "parts", or "suppliers", or "customers" (named "components" in LINC terminology). These were "manufactured", or "assembled", or "purchased", or "sold" (actions termed "events" in LINC terminology).
These componens and events were the "interface specifications" or "ispecs" and contained the database definitions, screen designs, and business rules of the application system.
LIRC (Logic and Information Report Compiler) was part of LINC and was developed to allow the programmer to produce reports (e.g. "purchase orders", "invoices", "credit notes", "consignment notes", "bills of sale"). The information in these reports were accessed by using various user-defined views of these components and events called "profiles".
Because reports run as a separate task (as a separate thread of execution) they could also be written to run as a background process; that is, it could put itself to sleep for a period of time or until woken, to perform some processing, then put itself to sleep again.
Part of the reason for the introduction of this new terminology was to make the system easier for programmers. It isolated them from a lot of the underlying technology. (Similarly, different names were intentionally used for control structures: DO.WHEN rather than IF or LOOP, and LOOK.UP or DETERMINE rather than READ, with the OPEN and CLOSE statements generated automatically.)
What allowed LINC to make programmers much more efficient and the application systems they produced easier to read and maintain, and differentiated it from being simply yet another third generation
high level language, was LINC's assumption, use of, and total reliance on all of the facilities available, and packaged, with the Burroughs computer for which it was written: operating system, job control language, COBOL programming language, database management system, network definition, user terminal, etc. (See also "history" below.)
From version 11, its character changed. Where LINC (and LIRC) specifications had previously been held in source-code files, they were now held in a database (designed and developed using the LINC 4GL) and subject to rigorous automatic validation. The new LINC-based system in which specifications were stored was named LINC interactive or LINC Development Environment (LDE).
Extensive reliance on terminal "screen painting" (i.e. "mocking"-up a CRT
data-entry screen) was used to assist system definition. e.g. to define a components database attributes (name, length, alpha(numeric), validation rules, etc., and for defining report layouts).
In the early '90s, a new PC-based tool for developing LINC specifications was released, the LINC Development Assistant (LDA). LDA was written in a mixture of Smalltalk and C++ rather than the LINC 4GL (the latter of which was not intended to run on a personal computer). From version 17, it was intended that all development be done with LDA.
Now LINC is known as Unisys Enterprise Application Environment (EAE) and can generate COBOL code for Burroughs & Sperry mainframes, Microsoft Windows
, and various Unix
and Linux
platforms. It will also generate GUI front-end clients in
in addition to compiling generated code and deploying databases to correspond with the specification. Databases supported include Burroughs DMSII
, Sperry RDMS, Oracle database
and Microsoft SQL Server
.
Unisys is now replacing it with Unisys Agile Business Suite, a new suite promoting object-oriented features which runs with Microsoft Visual Studio.
computer programmers (Gilbert Simpson
and Peter Hoskins) while working in Saudi Arabia
in the early 1980s. It was first developed exclusively for operation with a single model of Burroughs computer system comprising a totally integrated system of:
etc.
The LINC system created 3rd GL
COBOL (application), DMSII (database definition), NDLII (network description), and WFL (job control) source code. The job control statements were themselves subsequently run to compile the other elements and create an integrated system of database, applications, and user terminal network.
Burroughs purchased rights to sell the product in 1982, while product development was retained by the original inventors. An early requirement was to extend the product for use with the Burroughs mid-range and large scale computing platforms.
After Burroughs merged with Sperry Corporation
to form Unisys
, the language was extended to be used on Sperry's UNIVAC 1100/2200 series
machines also.
Subsequently a New Zealand development centre was set up in Christchurch to develop the product. Ownership was later on transferred to Unisys and the product and mainframe computer centre resources transitioned to Unisys ACUS
, the "Australian Centre for Unisys Software" in Sydney Australia.
LINC is (was) supported on the following platforms:
Development work was by ACUS
Unisys, but was transitioned from ACUS to an Indian outsourcing operation in early 2008. Eventually, the product was sold to over 4,000 clients worldwide.
systems readily available from many other sources (especially IBM
). The cost of purchasing and customising an existing product (e.g. the Hogan retail banking system) is perceived as less expensive/risk than using LINC to create, from scratch, an entire business system with all its rules.
Other weaknesses arise mostly from its dependence and basis on Burroughs DMS and COBOL, which differ greatly from other computing platforms.
Fourth-generation programming language
A fourth-generation programming language is a programming language or programming environment designed with a specific purpose in mind, such as the development of commercial business software. In the history of computer science, the 4GL followed the 3GL in an upward trend toward higher...
, used mostly on Unisys
Unisys
Unisys Corporation , headquartered in Blue Bell, Pennsylvania, United States, and incorporated in Delaware, is a long established business whose core products now involves computing and networking.-History:...
computer systems.
Background
LINC was originally developed as a short-cut (or template) by two computer application programmers to reproduce and automate the production of computer applications for different companies, but which had similar requirements and specifications. The requirements were similar, because the companies followed a common, generic, business model.That is, these businesses dealt with "commodities", or "parts", or "suppliers", or "customers" (named "components" in LINC terminology). These were "manufactured", or "assembled", or "purchased", or "sold" (actions termed "events" in LINC terminology).
These componens and events were the "interface specifications" or "ispecs" and contained the database definitions, screen designs, and business rules of the application system.
LIRC (Logic and Information Report Compiler) was part of LINC and was developed to allow the programmer to produce reports (e.g. "purchase orders", "invoices", "credit notes", "consignment notes", "bills of sale"). The information in these reports were accessed by using various user-defined views of these components and events called "profiles".
Because reports run as a separate task (as a separate thread of execution) they could also be written to run as a background process; that is, it could put itself to sleep for a period of time or until woken, to perform some processing, then put itself to sleep again.
Part of the reason for the introduction of this new terminology was to make the system easier for programmers. It isolated them from a lot of the underlying technology. (Similarly, different names were intentionally used for control structures: DO.WHEN rather than IF or LOOP, and LOOK.UP or DETERMINE rather than READ, with the OPEN and CLOSE statements generated automatically.)
What allowed LINC to make programmers much more efficient and the application systems they produced easier to read and maintain, and differentiated it from being simply yet another third generation
Third-generation programming language
A third-generation programming language is a refinement of a second-generation programming language. The second generation of programming languages brought logical structure to software. The third generation brought refinements to make the languages more programmer-friendly...
high level language, was LINC's assumption, use of, and total reliance on all of the facilities available, and packaged, with the Burroughs computer for which it was written: operating system, job control language, COBOL programming language, database management system, network definition, user terminal, etc. (See also "history" below.)
From version 11, its character changed. Where LINC (and LIRC) specifications had previously been held in source-code files, they were now held in a database (designed and developed using the LINC 4GL) and subject to rigorous automatic validation. The new LINC-based system in which specifications were stored was named LINC interactive or LINC Development Environment (LDE).
Extensive reliance on terminal "screen painting" (i.e. "mocking"-up a CRT
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...
data-entry screen) was used to assist system definition. e.g. to define a components database attributes (name, length, alpha(numeric), validation rules, etc., and for defining report layouts).
In the early '90s, a new PC-based tool for developing LINC specifications was released, the LINC Development Assistant (LDA). LDA was written in a mixture of Smalltalk and C++ rather than the LINC 4GL (the latter of which was not intended to run on a personal computer). From version 17, it was intended that all development be done with LDA.
Now LINC is known as Unisys Enterprise Application Environment (EAE) and can generate COBOL code for Burroughs & Sperry mainframes, Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
, and various Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
and Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
platforms. It will also generate GUI front-end clients in
- JavaJava (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...
- Visual Basic 6 clients
- Active Server PagesActive Server PagesActive Server Pages , also known as Classic ASP or ASP Classic, was Microsoft's first server-side script engine for dynamically-generated Web pages. Initially released as an add-on to Internet Information Services via the Windows NT 4.0 Option Pack Active Server Pages (ASP), also known as Classic...
- Web serviceWeb serviceA Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...
s for Microsoft IIS - ASP.NETASP.NETASP.NET is a Web application framework developed and marketed by Microsoft to allow programmers to build dynamic Web sites, Web applications and Web services. It was first released in January 2002 with version 1.0 of the .NET Framework, and is the successor to Microsoft's Active Server Pages ...
- VB.NET
in addition to compiling generated code and deploying databases to correspond with the specification. Databases supported include Burroughs DMSII
Unisys DMSII
The Unisys Data Management System II is a database system originally created by the Burroughs Corporation in 1972. It was available on the Burroughs Small , Medium and Large System product lines...
, Sperry RDMS, Oracle database
Oracle database
The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....
and Microsoft SQL Server
Microsoft SQL Server
Microsoft SQL Server is a relational database server, developed by Microsoft: It is a software product whose primary function is to store and retrieve data as requested by other software applications, be it those on the same computer or those running on another computer across a network...
.
Unisys is now replacing it with Unisys Agile Business Suite, a new suite promoting object-oriented features which runs with Microsoft Visual Studio.
History
LINC was originally developed by two New ZealandNew Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
computer programmers (Gilbert Simpson
Gilbert Simpson
Sir Gilbert "Gil" Simpson, KNZM, QSM is a New Zealand businessman and computer programmer.-Early life:He was born in Christchurch, New Zealand and raised in the Waikato...
and Peter Hoskins) while working in Saudi Arabia
Saudi Arabia
The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...
in the early 1980s. It was first developed exclusively for operation with a single model of Burroughs computer system comprising a totally integrated system of:
- B1000Burroughs B1700The Burroughs B1000 Series of computers consisted of three major generations which were the B1700, B1800, and B1900 series machines originally introduced in the 1970s and continued later on....
hardware, - MCPMCP (Burroughs Large Systems)The MCP is the proprietary operating system of the Burroughs large systems including the Unisys Clearpath/MCP systems....
operating system, - COBOLCOBOLCOBOL 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....
application programming language, - WFL job control languageWork Flow LanguageWork Flow Language, or WFL is the process control language for the Burroughs large systems, including the Unisys ClearPath/MCP series, and their operating system Master Control Program. Developed soon after the B5000 in 1961, WFL is the ClearPath equivalent of the Job Control Language on IBM...
, - DMS IIUnisys DMSIIThe Unisys Data Management System II is a database system originally created by the Burroughs Corporation in 1972. It was available on the Burroughs Small , Medium and Large System product lines...
database management system, - NDLII Network Definition Language
- MT983/ET1100 CRTComputer displayA monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...
(user terminal),
etc.
The LINC system created 3rd GL
Third-generation programming language
A third-generation programming language is a refinement of a second-generation programming language. The second generation of programming languages brought logical structure to software. The third generation brought refinements to make the languages more programmer-friendly...
COBOL (application), DMSII (database definition), NDLII (network description), and WFL (job control) source code. The job control statements were themselves subsequently run to compile the other elements and create an integrated system of database, applications, and user terminal network.
Burroughs purchased rights to sell the product in 1982, while product development was retained by the original inventors. An early requirement was to extend the product for use with the Burroughs mid-range and large scale computing platforms.
After Burroughs merged with Sperry Corporation
Sperry Corporation
Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the twentieth century...
to form Unisys
Unisys
Unisys Corporation , headquartered in Blue Bell, Pennsylvania, United States, and incorporated in Delaware, is a long established business whose core products now involves computing and networking.-History:...
, the language was extended to be used on Sperry's UNIVAC 1100/2200 series
UNIVAC 1100/2200 series
The UNIVAC 1100/2200 series is a series of compatible 36-bit computer systems, beginning with the UNIVAC 1107 in 1962, initially made by Sperry Rand...
machines also.
Subsequently a New Zealand development centre was set up in Christchurch to develop the product. Ownership was later on transferred to Unisys and the product and mainframe computer centre resources transitioned to Unisys ACUS
Acus
Acus is a genus of sea snails, marine gastropod mollusks in the family Terebridae, the auger snails.The genus name Acus belongs to the Pisces. Therefore Acus Gray, 1847 is no longer accepted, since it is a junior homonym of Acus Lacépède, 1803...
, the "Australian Centre for Unisys Software" in Sydney Australia.
LINC is (was) supported on the following platforms:
- ClearPath A-Series
- ClearPath 2200
- Unix SUN Solaris
- Unix IBM RS6000
- Unix HP9000
- Unix Sequent
- Unixware
- Windows Server
Development work was by ACUS
Acus
Acus is a genus of sea snails, marine gastropod mollusks in the family Terebridae, the auger snails.The genus name Acus belongs to the Pisces. Therefore Acus Gray, 1847 is no longer accepted, since it is a junior homonym of Acus Lacépède, 1803...
Unisys, but was transitioned from ACUS to an Indian outsourcing operation in early 2008. Eventually, the product was sold to over 4,000 clients worldwide.
Strengths
- It provides an intuitive and easy-to-understand interface to the Burroughs DMS and COBOL programming.
- As it has been modernised to support different platforms, it facilitates migration between platforms and databases.
- By confining a specification in a database, the entire design can be kept in a single design and development environment.
- Once generated, the code is absolutely consistent with its design specification.
- A client interface is always consistent with a system generated at the same time.
- The system's database access code is always consistent with the system's database tables.
Weaknesses
Principally, LINC fails to compete against myriad turnkeyTurnkey
A turn-key or a turn-key project is a type of project that is constructed by a developer and sold or turned over to a buyer in a ready-to-use condition.-Common usage:...
systems readily available from many other sources (especially 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...
). The cost of purchasing and customising an existing product (e.g. the Hogan retail banking system) is perceived as less expensive/risk than using LINC to create, from scratch, an entire business system with all its rules.
Other weaknesses arise mostly from its dependence and basis on Burroughs DMS and COBOL, which differ greatly from other computing platforms.
- People entering the industry or from a Unix / Windows background may struggle to adjust to this different paradigm.
- Functionality can be limited by the need to support multiple platforms. You can't use optimal Oracle structures or queries if the mainframe platforms don't support them.
Resellers
- Asysco, http://www.asysco.com, provider of utilities for assisting development with the LINC 4GL and their own competing solution: Asysco Migration Technologyhttp://www.asysco.com/index.php?D=3
- Chesapeake, consulting and development services for LINC developers, http://chspk.com/
- Eagle Computer Associates, provider of utilities and services for LINC developers, http://www.eagleca.com/
- Information Exchange Group, provider of utilities for assisting development with LINC, http://www.ieg-inc.com/
Migration
- Asysco, the leading provider in automated mainframeMainframeMainframe may refer to either of the following:* Mainframe computer, large and powerful data processing systems* Mainframe Entertainment, a Canadian computer animation and design company* Mainframe , a 1980s Electropop band...
migrations, http://www.asysco.com, with their unique Asysco Migration Technology., http://www.asysco.com - Vista Verde Soft, http://www.vistaverdesoft.com ,From Linc to Java and Oracle.
- ArtinSoft, Migration specialist from Linc to Java, http://www.artinsoft.com
- Jade Software Corporation Ltd - Inventors of LINC 4GL, http://www.jadeworld.com/
- L2EE, J2EE run-time for LINC Applications, http://l2ee.com
- MSS International Ltd - Migration for Unisys to Open Platform. Specifically Linc to Oracle Pl/Sql or Java, http://www.mssint.com/
- XSEED, Migration to Java is the XSEED best work. http://www.xseed.com.br