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51-425: PL-1 or PL1 may refer to: PL/I , a programming language Lamson PL-1 Quark , a glider Pazmany PL-1 , a trainer aircraft K-5 (missile) [REDACTED] Topics referred to by the same term This disambiguation page lists articles associated with the same title formed as a letter–number combination. If an internal link led you here, you may wish to change

102-709: A Roman numeral "I"). The first definition appeared in April 1964. IBM took NPL as a starting point and completed the design to a level that the first compiler could be written: the NPL definition was incomplete in scope and in detail. Control of the PL/I language was vested initially in the New York Programming Center and later at the IBM UK Laboratory at Hursley . The SHARE and GUIDE user groups were involved in extending

153-589: A common level of PL/I language and aimed to replace the PL/I F compiler. The checkout compiler is a rewrite of PL/I F in BSL, IBM's PL/I-like proprietary implementation language (later PL/S ). The performance objectives set for the compilers are shown in an IBM presentation to the BCS. The compilers had to produce identical results – the Checkout Compiler is used to debug programs that would then be submitted to

204-486: A compiler backend named the VAX Code Generator (VCG) created by a team led by Dave Cutler . The front end was designed by Robert Freiburghouse, and was ported to VAX/VMS from Multics . It runs on VMS on VAX and Alpha , and on Tru64 . During the 1990s, Digital sold the compiler to UniPrise Systems , who later sold it to a company named Kednos. Kednos marketed the compiler as Kednos PL/I until October 2016 when

255-480: A condition prefix enabling or disabling a computational condition – e.g. (NOSIZE) ). Entry and label names may be single identifiers or identifiers followed by a subscript list of constants (as in L(12,2):A=0; ). A sequence of statements becomes a group when preceded by a DO statement and followed by an END statement. Groups may include nested groups and begin blocks. The IF statement specifies

306-466: A distinctive concise and readable syntax. Many principles and capabilities combined to give the language its character and were important in meeting the language's goals: The language is designed to provide sufficient facilities to be able to satisfy the needs of all programmers, regardless of what problems the language is being applied to. The summary is extracted from the ANSI PL/I Standard and

357-588: A group or a single statement as the THEN part and the ELSE part (see the sample program). The group is the unit of iteration. The begin block ( BEGIN; stmt-list END; ) may contain declarations for names and internal procedures local to the block. A procedure starts with a PROCEDURE statement and is terminated syntactically by an END statement. The body of a procedure is a sequence of blocks, groups, and statements and contains declarations for names and procedures local to

408-451: A joint effort of ECMA TC/10 and ANSI X3J1. A subset of the GY33-6003 document was offered to the joint effort by IBM and became the base document for standardization. The major features omitted from the base document were multitasking and the attributes for program optimization (e.g. NORMAL and ABNORMAL ). Proposals to change the base document were voted upon by both committees. In

459-445: A limited subset of the PL/I language in addition to BASIC and a remote job entry facility. PL/C , a dialect for teaching, a compiler developed at Cornell University , had the unusual capability of never failing to compile any program through the use of extensive automatic correction of many syntax errors and by converting any remaining syntax errors to output statements. The language was almost all of PL/I as implemented by IBM. PL/C

510-724: A major attempt to speed up PL/I code to compete with Fortran object code, PL/I F Release 5 does substantial program optimization of DO-loops facilitated by the REORDER option on procedures. A version of PL/I F was released on the TSS/360 timesharing operating system for the System/360 Model 67 , adapted at the IBM Mohansic Lab. The IBM La Gaude Lab in France developed "Language Conversion Programs" to convert Fortran, Cobol, and Algol programs to

561-478: A number of schools built their own subsets of PL/I and their own interactive support. Examples are: In the 1960s and early 1970s, Allen-Babcock implemented the Remote Users of Shared Hardware (RUSH) time sharing system for an IBM System/360 Model 50 with custom microcode and subsequently implemented IBM's CPS , an interactive time-sharing system for OS/360 aimed at teaching computer science basics, offered

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612-470: A single pass over the partially-compiled program, usually held in memory. Aspects of the language were still being designed as PL/I F was implemented, so some were omitted until later releases. PL/I RECORD I/O was shipped with PL/I F Release 2. The list processing functions  – Based Variables, Pointers, Areas and Offsets and LOCATE-mode I/O  – were first shipped in Release 4. In

663-471: A wide set of functions available to verify and manipulate them. In the 1950s and early 1960s, business and scientific users programmed for different computer hardware using different programming languages. Business users were moving from Autocoders via COMTRAN to COBOL , while scientific users programmed in Fortran , ALGOL , GEORGE , and others. The IBM System/360 (announced in 1964 and delivered in 1966)

714-531: Is a compatible super-set of the PL/I Standard and of the earlier IBM compilers. Major topics added to PL/I were: IBM Hursley IBM Hursley is a research and development laboratory belonging to International Business Machines in the village of Hursley , Hampshire , England . Established in Hursley House , an 18th-century Queen Anne style mansion in 1958, the facility has been instrumental in

765-451: Is couched as a formal definition using a "PL/I Machine" to specify the semantics. It was the first programming language standard to be written as a semi-formal definition. A "PL/I General-Purpose Subset" ("Subset-G") standard was issued by ANSI in 1981 and a revision published in 1987. The General Purpose subset was widely adopted as the kernel for PL/I implementations. PL/I was first implemented by IBM, at its Hursley Laboratories in

816-519: Is credited with ensuring PL/I had the CHARACTER data type. The language was first specified in detail in the manual "PL/I Language Specifications. C28-6571", written in New York in 1965, and superseded by "PL/I Language Specifications. GY33-6003", written by Hursley in 1967. IBM continued to develop PL/I in the late sixties and early seventies, publishing it in the GY33-6003 manual. These manuals were used by

867-437: Is terminated by a semi-colon. The maximum length of a statement is implementation defined. A comment may appear anywhere in a program where a space is permitted and is preceded by the characters forward slash, asterisk and is terminated by the characters asterisk, forward slash (i.e. /* This is a comment. */ ). Statements may have a label-prefix introducing an entry name ( ENTRY and PROCEDURE statements) or label name, and

918-674: The Picture-for-arithmetic type is encoded within the picture-specification . The mode is specified separately, with the picture specification applied to both the real and the imaginary parts. Values are computed by expressions written using a specific set of operations and builtin functions, most of which may be applied to aggregates as well as to single values, together with user-defined procedures which, likewise, may operate on and return aggregate as well as single values. The assignment statement assigns values to one or more variables. There are no reserved words in PL/I. A statement

969-613: The Multics group and other early implementers. The first compiler was delivered in 1966. The Standard for PL/I was approved in 1976. The goals for PL/I evolved during the early development of the language. Competitiveness with COBOL's record handling and report writing was required. The language's scope of usefulness grew to include system programming and event-driven programming . Additional goals for PL/I were: To achieve these goals, PL/I borrowed ideas from contemporary languages while adding substantial new capabilities and casting it with

1020-676: The PL/I preprocessor are not in the Standard but are supported in the PL/I F compiler and some other implementations are discussed in the Language evolution section.) Names may be declared to represent data of the following types, either as single values, or as aggregates in the form of arrays, with a lower-bound and upper-bound per dimension, or structures (comprising nested structure, array and scalar variables): The arithmetic type comprises these attributes: The base, scale, precision and scale factor of

1071-511: The ANSI PL/I General-Purpose Subset Standard. A PL/I program consists of a set of procedures, each of which is written as a sequence of statements. The %INCLUDE construct is used to include text from other sources during program translation. All of the statement types are summarized here in groupings which give an overview of the language (the Standard uses this organization). (Features such as multi-tasking and

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1122-501: The IBM scientific users group, to propose these extensions to Fortran. Given the constraints of Fortran, they were unable to do this and embarked on the design of a new programming language based loosely on ALGOL labeled NPL . This acronym conflicted with that of the UK's National Physical Laboratory and was replaced briefly by MPPL (MultiPurpose Programming Language) and, in 1965, with PL/I (with

1173-474: The Optimizer. Given that the compilers had entirely different designs and were handling the full PL/I language this goal was challenging: it was achieved. IBM introduced new attributes and syntax including BUILTIN , case statements ( SELECT / WHEN / OTHERWISE ), loop controls ( ITERATE and LEAVE ) and null argument lists to disambiguate, e.g., DATE () . The PL/I optimizing compiler took over from

1224-432: The PL/I F compiler and was IBM's workhorse compiler from the 1970s to the 1990s. Like PL/I F, it is a multiple pass compiler with a 44 kilobyte design point, but it is an entirely new design. Unlike the F compiler, it has to perform compile time evaluation of constant expressions using the run-time library, reducing the maximum memory for a compiler phase to 28 kilobytes. A second-time around design, it succeeded in eliminating

1275-464: The PL/I F level of PL/I. The PL/I D compiler, using 16 kilobytes of memory, was developed by IBM Germany for the DOS/360 low end operating system. It implements a subset of the PL/I language requiring all strings and arrays to have fixed extents, thus simplifying the run-time environment. Reflecting the underlying operating system, it lacks dynamic storage allocation and the controlled storage class. It

1326-632: The United Kingdom, as part of the development of System/360 . The first production PL/I compiler was the PL/I F compiler for the OS/360 Operating System, built by John Nash's team at Hursley in the UK: the runtime library team was managed by I.M. (Nobby) Clarke. The PL/I F compiler was written entirely in System/360 assembly language. Release 1 shipped in 1966. OS/360 is a real-memory environment and

1377-624: The University of New South Wales, PLUM by Marvin Victor Zelkowitz at the University of Maryland., and PLUTO from the University of Toronto. In a major revamp of PL/I, IBM Santa Teresa in California launched an entirely new compiler in 1992. The initial shipment was for OS/2 and included most ANSI-G features and many new PL/I features. Subsequent releases provided additional platforms ( MVS , VM , OS/390 , AIX and Windows ), but as of 2021,

1428-518: The University of Toronto produced the SP/k compilers which supported a sequence of subsets of PL/I called SP/1, SP/2, SP/3, ..., SP/8 for teaching programming. Programs that ran without errors under the SP/k compilers produced the same results under other contemporary PL/I compilers such as IBM's PL/I F compiler, IBM's checkout compiler or Cornell University's PL/C compiler. Other examples are PL0 by P. Grouse at

1479-490: The annoyances of PL/I F such as cascading diagnostics. It was written in S/360 Macro Assembler by a team, led by Tony Burbridge, most of whom had worked on PL/I F. Macros were defined to automate common compiler services and to shield the compiler writers from the task of managing real-mode storage, allowing the compiler to be moved easily to other memory models. The gamut of program optimization techniques developed for

1530-693: The code into 28 kb sections, IBM Poughkeepsie was finally ready to ship virtual memory support in OS/360). It supported the batch programming environments and, under TSO and CMS, it could be run interactively. This compiler went through many versions covering all mainframe operating systems including the operating systems of the Japanese plug-compatible machines (PCMs). The compiler has been superseded by "IBM PL/I for OS/2, AIX, Linux, z/OS" below. The PL/I checkout compiler, (colloquially "The Checker") announced in August 1970

1581-416: The company ceased trading. In the late 1960s and early 1970s, many US and Canadian universities were establishing time-sharing services on campus and needed conversational compiler/interpreters for use in teaching science, mathematics, engineering, and computer science. Dartmouth was developing BASIC , but PL/I was a popular choice, as it was concise and easy to teach. As the IBM offerings were unsuitable,

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1632-502: The compiler was designed for systems with as little as 64 kilobytes of real storage – F being 64 kB in S/360 parlance. To fit a large compiler into the 44 kilobytes of memory available on a 64-kilobyte machine, the compiler consists of a control phase and a large number of compiler phases (approaching 100). The phases are brought into memory from disk, one at a time, to handle particular language features and aspects of compilation. Each phase makes

1683-417: The contemporary IBM Fortran H compiler were deployed: the Optimizer equaled Fortran execution speeds in the hands of good programmers. Announced with IBM S/370 in 1970, it shipped first for the DOS/360 operating system in August 1971, and shortly afterward for OS/360, and the first virtual memory IBM operating systems OS/VS1 , MVS , and VM/CMS . (The developers were unaware that while they were shoehorning

1734-611: The development of IBM's software technologies since the 1950s. It is still the home of development for CICS and MQ technology. Among the software developed by IBM Hursley is the Customer Information Control System (CICS), used in ATMs, which was the first Hursley product with a billion dollars in annual revenue. Initially, IBM just used the House and its grounds. In 1963 it purchased 100 acres (405,000 m ) of land surrounding

1785-490: The event that the committees disagreed, the chairs, initially Michael Marcotty of General Motors and C.A.R. Hoare representing ICL had to resolve the disagreement. In addition to IBM, Honeywell , CDC , Data General , Digital Equipment Corporation , Prime Computer , Burroughs , RCA , and Univac served on X3J1 along with major users Eastman Kodak , MITRE , Union Carbide , Bell Laboratories , and various government and university representatives. Further development of

1836-506: The house and has since erected a large modern office complex employing over 1500 people. The facility is host to the IBM Client Centre, which offers potential clients a secure environment where they can test company software and work with staff experts on best practices, proof of concept, and proof of technology. Hursley House itself, a Grade II* listed building, is still used as an Executive Briefing Centre. The lower ground floor of

1887-476: The language and had a role in IBM's process for controlling the language through their PL/I Projects. The experience of defining such a large language showed the need for a formal definition of PL/I. A project was set up in 1967 in IBM Laboratory Vienna to make an unambiguous and complete specification. This led in turn to one of the first large scale Formal Methods for development, VDM . Fred Brooks

1938-477: The language occurred in the standards bodies, with continuing improvements in structured programming and internal consistency, and with the omission of the more obscure or contentious features. As language development neared an end, X3J1/TC10 realized that there were a number of problems with a document written in English text. Discussion of a single item might appear in multiple places which might or might not agree. It

1989-413: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=PL-1&oldid=933057739 " Category : Letter–number combination disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages PL/I The PL/1 ANSI standard, X3.53-1976,

2040-704: The only supported platforms are z/OS and AIX. IBM continued to add functions to make PL/I fully competitive with other languages (particularly C and C++) in areas where it had been overtaken. The corresponding "IBM Language Environment" supports inter-operation of PL/I programs with Database and Transaction systems, and with programs written in C, C++, and COBOL, the compiler supports all the data types needed for intercommunication with these languages. The PL/I design principles were retained and withstood this major extension, comprising several new data types, new statements and statement options, new exception conditions, and new organisations of program source. The resulting language

2091-499: The procedure or EXTERNAL to the procedure. An ON-unit is a single statement or block of statements written to be executed when one or more of these conditions occur: a computational condition , or an Input/Output condition, or one of the conditions: A declaration of an identifier may contain one or more of the following attributes (but they need to be mutually consistent): Current compilers from Micro Focus , and particularly that from IBM implement many extensions over

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2142-592: The standardized version of the language. The IBM extensions are summarised in the Implementation sub-section for the compiler later. Although there are some extensions common to these compilers the lack of a current standard means that compatibility is not guaranteed. Language standardization began in April 1966 in Europe with ECMA TC10. In 1969 ANSI established a "Composite Language Development Committee", nicknamed "Kludge", later renamed X3J1 PL/I. Standardization became

2193-428: The target address and a description of the referenced item, thus permitting "bad" pointer use to be diagnosed. In a conversational environment when an error is detected, control is passed to the user who can inspect any variables, introduce debugging statements and edit the source program. Over time the debugging capability of mainframe programming environments developed most of the functions offered by this compiler and it

2244-571: Was a very fast compiler. SL/1 (Student Language/1, Student Language/One or Subset Language/1) was a PL/I subset, initially available late 1960s, that ran interpretively on the IBM 1130 ; instructional use was its strong point. PLAGO , created at the Polytechnic Institute of Brooklyn , used a simplified subset of the PL/I language and focused on good diagnostic error messages and fast compilation times. The Computer Systems Research Group of

2295-400: Was designed as a common machine architecture for both groups of users, superseding all existing IBM architectures. Similarly, IBM wanted a single programming language for all users. It hoped that Fortran could be extended to include the features needed by commercial programmers. In October 1963 a committee was formed composed originally of three IBMers from New York and three members of SHARE ,

2346-504: Was designed to speed and improve the debugging of PL/I programs. The team was led by Brian Marks. The three-pass design cut the time to compile a program to 25% of that taken by the F Compiler. It can be run from an interactive terminal, converting PL/I programs into an internal format, "H-text". This format is interpreted by the Checkout compiler at run-time, detecting virtually all types of errors. Pointers are represented in 16 bytes, containing

2397-564: Was developed using the TMG compiler-compiler. The influential Multics PL/I compiler was the source of compiler technology used by a number of manufacturers and software groups. EPL was a system programming language and a dialect of PL/I that had some capabilities absent in the original PL/I. The Honeywell PL/I compiler (for Series 60) is an implementation of the full ANSI X3J1 standard. The PL/I Optimizer and Checkout compilers produced in Hursley support

2448-429: Was difficult to determine if there were omissions as well as inconsistencies. Consequently, David Beech (IBM), Robert Freiburghouse (Honeywell), Milton Barber (CDC), M. Donald MacLaren ( Argonne National Laboratory ), Craig Franklin (Data General), Lois Frampton (Digital Equipment Corporation), and editor, D.J. Andrews of IBM undertook to rewrite the entire document, each producing one or more complete chapters. The standard

2499-415: Was published in 1976. PL/I's main domains are data processing , numerical computation , scientific computing , and system programming . It supports recursion , structured programming , linked data structure handling, fixed-point , floating-point , complex , character string handling, and bit string handling. The language syntax is English-like and suited for describing complex data formats with

2550-409: Was shipped within a year of PL/I F. Compilers were implemented by several groups in the early 1960s. The Multics project at MIT , one of the first to develop an operating system in a high-level language , used Early PL/I (EPL), a subset dialect of PL/I, as their implementation language in 1964. EPL was developed at Bell Labs and MIT by Douglas McIlroy , Robert Morris , and others. Initially, it

2601-478: Was withdrawn (in the 1990s?) Perhaps the most commercially successful implementation aside from IBM's was Digital Equipment Corporation's VAX-11 PL/I, later known as VAX PL/I, then DEC PL/I. The implementation is "a strict superset of the ANSI X3.4-1981 PL/I General Purpose Subset and provides most of the features of the new ANSI X3.74-1987 PL/I General Purpose Subset", and was first released in 1980. It originally used

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