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63-726: IBM had earlier products in industrial control market, notably the IBM 1800 which appeared in 1964. However, there was minimal resemblance in architecture or software between the 1800 series and the System/7. System/7 was designed and assembled in Boca Raton, Florida . The processor designation for the system was IBM 5010 . There were 8 registers which were mostly general purpose (capable of being used equally in instructions) although R0 had some extra capabilities for indexed memory access or system I/O . Later models may have been faster, but

126-572: A Formula Translating System , and printed the name with small caps , Fortran . Other sources suggest the name stands for Formula Translator , or Formula Translation . Early IBM computers did not support lowercase letters, and the names of versions of the language through FORTRAN 77 were usually spelled in all- uppercase . FORTRAN 77 was the last version in which the Fortran character set included only uppercase letters. The official language standards for Fortran have referred to

189-448: A high-level programming language replacement. John Backus said during a 1979 interview with Think , the IBM employee magazine, "Much of my work has come from being lazy. I didn't like writing programs, and so, when I was working on the IBM 701 , writing programs for computing missile trajectories, I started work on a programming system to make it easier to write programs." The language

252-501: A card reader to be compiled. Punched card codes included no lower-case letters or many special characters, and special versions of the IBM 026 keypunch were offered that would correctly print the re-purposed special characters used in FORTRAN. Reflecting punched card input practice, Fortran programs were originally written in a fixed-column format, with the first 72 columns read into twelve 36-bit words. A letter "C" in column 1 caused

315-511: A character data type (Fortran 77), structured programming , array programming , modular programming , generic programming (Fortran 90), parallel computing ( Fortran 95 ), object-oriented programming (Fortran 2003), and concurrent programming (Fortran 2008). Since April 2024, Fortran has ranked among the top ten languages in the TIOBE index , a measure of the popularity of programming languages. The first manual for FORTRAN describes it as

378-440: A combination of the following: This is a solution specifically for on board ship navigation. It consists of the following hardware: There are also RPQs to ruggedize the hardware, provide interfaces to various navigation equipment and provide spares for on board ship. The operating system would more properly be called a monitor. IBM provided a wide variety of subroutines, mostly written in assembler, that could be configured into

441-590: A computer, an idea developed by J. Halcombe Laning and demonstrated in the Laning and Zierler system of 1952. A draft specification for The IBM Mathematical Formula Translating System was completed by November 1954. The first manual for FORTRAN appeared in October 1956, with the first FORTRAN compiler delivered in April 1957. Fortran produced efficient enough code for assembly language programmers to accept

504-452: A de facto standard), and Basic FORTRAN (based on FORTRAN II, but stripped of its machine-dependent features). The FORTRAN defined by the first standard, officially denoted X3.9-1966, became known as FORTRAN 66 (although many continued to term it FORTRAN IV, the language on which the standard was largely based). FORTRAN 66 effectively became the first industry-standard version of FORTRAN. FORTRAN 66 included: The above Fortran II version of

567-476: A limit of six characters in FORTRAN II. If A, B, and C cannot represent the sides of a triangle in plane geometry, then the program's execution will end with an error code of "STOP 1". Otherwise, an output line will be printed showing the input values for A, B, and C, followed by the computed AREA of the triangle as a floating-point number occupying ten spaces along the line of output and showing 2 digits after

630-407: A minimum set to support the peripherals and the application. The application-specific code was then written on top of the monitor stack. A minimal useful configuration would run with 8 kilobytes of memory, though in practice the size of the monitor and application program was usually 12kB and upwards. The maximum configuration had 64kB of memory. The advanced (for the time) semiconductor memory made

693-413: A number of significant features to address many of the shortcomings of FORTRAN 66: In this revision of the standard, a number of features were removed or altered in a manner that might invalidate formerly standard-conforming programs. (Removal was the only allowable alternative to X3J3 at that time, since the concept of " deprecation " was not yet available for ANSI standards.) While most of the 24 items in

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756-411: A problem. IBM's FORTRAN II appeared in 1958. The main enhancement was to support procedural programming by allowing user-written subroutines and functions which returned values with parameters passed by reference . The COMMON statement provided a way for subroutines to access common (or global ) variables. Six new statements were introduced: Over the next few years, FORTRAN II added support for

819-439: A program deck and add sequence numbers. Some early compilers, e.g., the IBM 650's, had additional restrictions due to limitations on their card readers. Keypunches could be programmed to tab to column 7 and skip out after column 72. Later compilers relaxed most fixed-format restrictions, and the requirement was eliminated in the Fortran 90 standard. Within the statement field, whitespace characters (blanks) were ignored outside

882-644: A ship equipped with the system was involved in a major incident. All clients were compensated for the removal. The product line was withdrawn from marketing on March 20, 1984. IBM's subsequent product in industrial control was the Series/1 , also designed at Boca Raton. IBM 1800 The IBM 1800 Data Acquisition and Control System (DACS) was a process control variant of the IBM 1130 with two extra instructions (CMP and DCM), extra I/O capabilities, 'selector channel like' cycle-stealing capability and three hardware index registers. IBM announced and introduced

945-409: A simple means for FORTRAN 77 programmers to issue POSIX system calls. Over 100 calls were defined in the document – allowing access to POSIX-compatible process control, signal handling, file system control, device control, procedure pointing, and stream I/O in a portable manner. The much-delayed successor to FORTRAN 77, informally known as Fortran 90 (and prior to that, Fortran 8X ),

1008-456: A simplified, interpreted version of FORTRAN I (with only 12 statements not 32) for "load and go" operation was available (at least for the early IBM 1620 computer). Modern Fortran, and almost all later versions, are fully compiled, as done for other high-performance languages. The development of Fortran paralleled the early evolution of compiler technology , and many advances in the theory and design of compilers were specifically motivated by

1071-492: A stack is maintained by software and the return address is stored on the stack before the call is made and restored after the call returns. Although not specified in FORTRAN 77, many F77 compilers supported recursion as an option, and the Burroughs mainframes , designed with recursion built-in, did so by default. It became a standard in Fortran 90 via the new keyword RECURSIVE. This program, for Heron's formula , reads data on

1134-432: A tape reel containing three 5-digit integers A, B, and C as input. There are no "type" declarations available: variables whose name starts with I, J, K, L, M, or N are "fixed-point" (i.e. integers), otherwise floating-point. Since integers are to be processed in this example, the names of the variables start with the letter "I". The name of a variable must start with a letter and can continue with both letters and digits, up to

1197-414: A text literal. This allowed omitting spaces between tokens for brevity or including spaces within identifiers for clarity. For example, AVG OF X was a valid identifier, equivalent to AVGOFX , and 101010 DO101I = 1 , 101 was a valid statement, equivalent to 10101 DO 101 I = 1 , 101 because the zero in column 6 is treated as if it were a space (!), while 101010 DO101I = 1.101

1260-541: Is a third generation , compiled , imperative programming language that is especially suited to numeric computation and scientific computing . Fortran was originally developed by IBM . It first compiled correctly in 1958. Fortran computer programs have been written to support scientific and engineering applications, such as numerical weather prediction , finite element analysis , computational fluid dynamics , plasma physics , geophysics , computational physics , crystallography and computational chemistry . It

1323-506: Is a popular language for high-performance computing and is used for programs that benchmark and rank the world's fastest supercomputers . Fortran has evolved through numerous versions and dialects. In 1966, the American National Standards Institute (ANSI) developed a standard for Fortran to limit proliferation of compilers using slightly different syntax. Successive versions have added support for

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1386-460: Is designed to make the navigation of large ships safer and more efficient, by reducing the amount of data that bridge personnel needed to correlate while improving how it is presented. It provides five programmed functions: In the late 1970s IBM Chairman Frank Cary made the decision to not only withdraw this system but remove it from the ships that were equipped with it. This was done due to legal and reputational concerns about what would happen if

1449-419: Is determined by a random number generator suitably weighted according to whatever FREQUENCY statements have been provided. The first FORTRAN compiler reported diagnostic information by halting the program when an error was found and outputting an error code on its console. That code could be looked up by the programmer in an error messages table in the operator's manual, providing them with a brief description of

1512-507: Is to prepare for section 5 a table of predecessors (PRED table) which enumerates the basic blocks and lists for every basic block each of the basic blocks which can be its immediate predecessor in flow, together with the absolute frequency of each such basic block link. This table is obtained by running the program once in Monte-Carlo fashion, in which the outcome of conditional transfers arising out of IF-type statements and computed GO TO's

1575-495: The DOUBLE PRECISION and COMPLEX data types. Early FORTRAN compilers supported no recursion in subroutines. Early computer architectures supported no concept of a stack, and when they did directly support subroutine calls, the return location was often stored in one fixed location adjacent to the subroutine code (e.g. the IBM 1130 ) or a specific machine register ( IBM 360 et seq ), which only allows recursion if

1638-499: The IBM 7030 ("Stretch") computer, followed by versions for the IBM 7090 , IBM 7094 , and later for the IBM 1401 in 1966. By 1965, FORTRAN IV was supposed to be compliant with the standard being developed by the American Standards Association X3.4.3 FORTRAN Working Group. Between 1966 and 1968, IBM offered several FORTRAN IV compilers for its System/360 , each named by letters that indicated

1701-413: The 1800 Data Acquisition and Control System on November 30, 1964, describing it as "a computer that can monitor an assembly line, control a steel-making process or analyze the precise status of a missile during test firing." Unlike the 1130, which was a desk-like unit, the 1800 is packaged in 6 foot high, EIA Standard 19 inch racks , which are somewhat taller than the racks used by S/360 systems of

1764-516: The Heron program needs several modifications to compile as a Fortran 66 program. Modifications include using the more machine independent versions of the READ and WRITE statements, and removal of the unneeded FLOATF type conversion functions. Though not required, the arithmetic IF statements can be re-written to use logical IF statements and expressions in a more structured fashion. After

1827-575: The Hollerith edit descriptors in the FORMAT statements with quoted strings. It also uses structured IF and END IF statements, rather than GOTO / CONTINUE . The development of a revised standard to succeed FORTRAN 77 would be repeatedly delayed as the standardization process struggled to keep up with rapid changes in computing and programming practice. In the meantime, as the "Standard FORTRAN" for nearly fifteen years, FORTRAN 77 would become

1890-529: The IBM 5028), which was also how the machine would generally read its boot loader sequence. Since the semiconductor memory emptied when it lost power (in those days, losing memory when you switched off the power was regarded as a novelty) and the S/7 didn't have ROM, the machine had minimal capabilities at startup. It typically would read a tiny bootloader from the Teletype, and then that program would in turn read in

1953-534: The University of Waterloo's WATFOR and WATFIV were created to simplify the complex compile and link processes of earlier compilers. In the FORTRAN IV programming environment of the era, except for that used on Control Data Corporation (CDC) systems, only one instruction was placed per line. The CDC version allowed for multiple instructions per line if separated by a $ (dollar) character. The FORTRAN sheet

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2016-487: The conflict list (see Appendix A2 of X3.9-1978) addressed loopholes or pathological cases permitted by the prior standard but rarely used, a small number of specific capabilities were deliberately removed, such as: A Fortran 77 version of the Heron program requires no modifications to the Fortran 66 version. However this example demonstrates additional cleanup of the I/O statements, including using list-directed I/O, and replacing

2079-558: The decimal point, the .2 in F10.2 of the FORMAT statement with label 601. IBM also developed a FORTRAN III in 1958 that allowed for inline assembly code among other features; however, this version was never released as a product. Like the 704 FORTRAN and FORTRAN II, FORTRAN III included machine-dependent features that made code written in it unportable from machine to machine. Early versions of FORTRAN provided by other vendors suffered from

2142-640: The early history of FORTRAN was the decision by the American Standards Association (now American National Standards Institute (ANSI)) to form a committee sponsored by the Business Equipment Manufacturers Association (BEMA) to develop an American Standard Fortran . The resulting two standards, approved in March 1966, defined two languages, FORTRAN (based on FORTRAN IV, which had served as

2205-432: The entire card to be treated as a comment and ignored by the compiler. Otherwise, the columns of the card were divided into four fields: Columns 73 to 80 could therefore be used for identification information, such as punching a sequence number or text, which could be used to re-order cards if a stack of cards was dropped; though in practice this was reserved for stable, production programs. An IBM 519 could be used to copy

2268-624: The full program from another computer or from a high speed paper tape reader, or from an RPQ interface to a tape cassette player. Although many of the external devices used on the system used the ASCII character set, the internal operation of the system used the EBCDIC character set which IBM used on most systems. There were various specializations for process control. The CPU had 4 banks of registers each of different priority and it could respond to interrupts within one instruction cycle by switching to

2331-505: The generated code, the results of which were used to optimize the placement of basic blocks in memory—a very sophisticated optimization for its time. The Monte Carlo technique is documented in Backus et al.'s paper on this original implementation, The FORTRAN Automatic Coding System : The fundamental unit of program is the basic block ; a basic block is a stretch of program which has one entry point and one exit point. The purpose of section 4

2394-408: The higher priority set. Many specialized I/O devices could be configured for things such as analog measurement or signal generation, solid state or relay switching, or TTL digital input and output lines. The machine could be installed in an industrial environment without air conditioning, although there were feature codes available for safe operation in extreme environments. A System/7 is typically

2457-527: The historically most important dialect. An important practical extension to FORTRAN 77 was the release of MIL-STD-1753 in 1978. This specification, developed by the U.S. Department of Defense , standardized a number of features implemented by most FORTRAN 77 compilers but not included in the ANSI FORTRAN 77 standard. These features would eventually be incorporated into the Fortran 90 standard. The IEEE 1003.9 POSIX Standard, released in 1991, provided

2520-451: The increasing popularity of FORTRAN spurred competing computer manufacturers to provide FORTRAN compilers for their machines, so that by 1963 over 40 FORTRAN compilers existed. FORTRAN was provided for the IBM 1401 computer by an innovative 63-phase compiler that ran entirely in its core memory of only 8000 (six-bit) characters. The compiler could be run from tape, or from a 2200-card deck; it used no further tape or disk storage. It kept

2583-526: The language as "Fortran" with initial caps since Fortran 90. In late 1953, John W. Backus submitted a proposal to his superiors at IBM to develop a more practical alternative to assembly language for programming their IBM 704 mainframe computer . Backus' historic FORTRAN team consisted of programmers Richard Goldberg, Sheldon F. Best, Harlan Herrick, Peter Sheridan, Roy Nutt , Robert Nelson, Irving Ziller, Harold Stern, Lois Haibt , and David Sayre . Its concepts included easier entry of equations into

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2646-403: The machine fast but also expensive, so a lot of work went into minimizing the typical memory footprint of an application before deployment. The development tools normally ran on IBM's 360 computer system and the program image was then downloaded to a System/7 in a development lab by serial link. Up until 1975 at least it was rare to use disk overlays for the programs, with no support for that in

2709-666: The minimum amount of memory the compiler needed to run. The letters (F, G, H) matched the codes used with System/360 model numbers to indicate memory size, each letter increment being a factor of two larger: Digital Equipment Corporation maintained DECSYSTEM-10 Fortran IV (F40) for PDP-10 from 1967 to 1975. Compilers were also available for the UNIVAC 1100 series and the Control Data 6000 series and 7000 series systems. At about this time FORTRAN IV had started to become an important educational tool and implementations such as

2772-465: The need to generate efficient code for Fortran programs. The initial release of FORTRAN for the IBM 704 contained 32 statements , including: The arithmetic IF statement was reminiscent of (but not readily implementable by) a three-way comparison instruction (CAS—Compare Accumulator with Storage) available on the 704. The statement provided the only way to compare numbers—by testing their difference, with an attendant risk of overflow. This deficiency

2835-430: The operating system to be used. The machine was physically compact for its day, designed around chassis/gate configurations shared with other IBM machines such as the 3705 communications controller, and a typical configuration would take up one or two racks about 5 feet (1.5 m) high, the smallest System/7's were only about 3 feet (0.91 m) high. The usual console device was a Teletype Model 33 ASR (designated as

2898-420: The problem. Later, an error-handling subroutine to handle user errors such as division by zero, developed by NASA, was incorporated, informing users of which line of code contained the error. Before the development of disk files, text editors and terminals, programs were most often entered on a keypunch keyboard onto 80-column punched cards , one line to a card. The resulting deck of cards would be fed into

2961-788: The process industry plants worldwide. In June 2010 the last four operating IBM 1800s operating at Pickering Nuclear Generating Station in Pickering, Ontario , Canada were removed from service. Pickering is still using four ES-1800 computers which are IBM 1800 hardware emulators built by Cable & Computer Technologies. A video showing the end of the Pickering IBM 1800 boot sequence is available on YouTube Until 1984, Exxon USA (EUSA) had 18 IBM 1800 systems deployed at all 5 of its refineries. They were replaced with Honeywell TDC3000 process control systems. Fortran Fortran ( / ˈ f ɔːr t r æ n / ; formerly FORTRAN )

3024-519: The program in memory and loaded overlays that gradually transformed it, in place, into executable form, as described by Haines. This article was reprinted, edited, in both editions of Anatomy of a Compiler and in the IBM manual "Fortran Specifications and Operating Procedures, IBM 1401". The executable form was not entirely machine language ; rather, floating-point arithmetic, sub-scripting, input/output, and function references were interpreted, preceding UCSD Pascal P-code by two decades. GOTRAN ,

3087-621: The release of the FORTRAN 66 standard, compiler vendors introduced several extensions to Standard Fortran , prompting ANSI committee X3J3 in 1969 to begin work on revising the 1966 standard, under sponsorship of CBEMA , the Computer Business Equipment Manufacturers Association (formerly BEMA). Final drafts of this revised standard circulated in 1977, leading to formal approval of the new FORTRAN standard in April 1978. The new standard, called FORTRAN 77 and officially denoted X3.9-1978, added

3150-428: The same disadvantage. IBM began development of FORTRAN IV in 1961 as a result of customer demands. FORTRAN IV removed the machine-dependent features of FORTRAN II (such as READ INPUT TAPE ), while adding new features such as a LOGICAL data type , logical Boolean expressions , and the logical IF statement as an alternative to the arithmetic IF statement. FORTRAN IV was eventually released in 1962, first for

3213-494: The same vintage, but the internal gates and power supplies were very much the same. The IBM 1500 instructional system was introduced by IBM on March 31, 1966, and was based on an IBM 1130 or IBM 1800 computer. It supported up to 32 student work stations, each with a variety of audiovisual capabilities. Two 1800s with automatic switchover between them powered each IBM 1750, 2750 and 3750 Switching System . The IBM 1800 DACS consisted of: The IBM 1800 systems were used mainly in

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3276-533: The software tools. Hard disks, in the IBM Dolphin line of sealed cartridges, were available but expensive and were generally used as file systems storing data and executable programs (thereby eliminating the need to rely on the paper tape reader for system boot-up). Most work was done in a macro assembly language, with a fairly powerful macro language facility allowing great flexibility in code configuration and generation. Static variable binding, like Fortran ,

3339-494: The versions existing in 1973 had register to register operation times of 400 ns, memory read operations at 800 ns, memory write operations at 1.2 μs, and direct IO operations were generally 2.2 μs. The instruction set would be familiar to a modern RISC programmer, with the emphasis on register operations and few memory operations or fancy addressing modes. For example, the multiply and divide instructions were done in software and needed to be specifically built into

3402-655: Was also a large customer. However, the main use may have been for, what were at the time, classified military uses. This is an eclectic list of customers intended to show the variety of use cases for which the System/7 could be employed: IBM announced this system on October 15, 1973 and by the end of 1979 over 100 vessels were using it. This solution was the first navigational aid that the Control Engineering Department of Lloyds Register added to their list of Approved Control and Electrical Equipment . The System/7 Maritime Application/Bridge System

3465-480: Was also standard-conforming under Fortran 90, and either standard should have been usable to define its behavior. A small set of features were identified as "obsolescent" and were expected to be removed in a future standard. All of the functionalities of these early-version features can be performed by newer Fortran features. Some are kept to simplify porting of old programs but many were deleted in Fortran 95. Fortran 95 , published officially as ISO/IEC 1539-1:1997,

3528-430: Was divided into four fields, as described above. Two compilers of the time, IBM "G" and UNIVAC, allowed comments to be written on the same line as instructions, separated by a special character: "master space": V (perforations 7 and 8) for UNIVAC and perforations 12/11/0/7/8/9 (hexadecimal FF) for IBM. These comments were not to be inserted in the middle of continuation cards. Perhaps the most significant development in

3591-410: Was finally released as ISO/IEC standard 1539:1991 in 1991 and an ANSI Standard in 1992. In addition to changing the official spelling from FORTRAN to Fortran, this major revision added many new features to reflect the significant changes in programming practice that had evolved since the 1978 standard: Unlike the prior revision, Fortran 90 removed no features. Any standard-conforming FORTRAN 77 program

3654-412: Was instead 10101 DO101I = 1.101 , the assignment of 1.101 to a variable called DO101I . Note the slight visual difference between a comma and a period. Hollerith strings , originally allowed only in FORMAT and DATA statements, were prefixed by a character count and the letter H (e.g., 26HTHIS IS ALPHANUMERIC DATA. ), allowing blanks to be retained within the character string. Miscounts were

3717-411: Was later overcome by "logical" facilities introduced in FORTRAN IV. The FREQUENCY statement was used originally (and optionally) to give branch probabilities for the three branch cases of the arithmetic IF statement. It could also be used to suggest how many iterations a DO loop might run. The first FORTRAN compiler used this weighting to perform at compile time a Monte Carlo simulation of

3780-532: Was ported to the Series/1 environment as the very successful Event Driven Executive (EDX). The System/7 was designed to address the needs of specific " real-time " markets which required collecting and reacting to input and output (I/O) from analog devices (e.g. temperature sensors, industrial control devices). This was a very limited market at the time. Specific commercial uses included factory control systems and air conditioning energy control systems. AT&T

3843-772: Was required. System/7 programmers still needed to be aware of the actual instructions that were available for use. Much development work was done on S/360 or S/370 using a variation of the HLASM program geared to the MSP/7 macro language. To provide more flexibility in programming the System/7, a group in the IBM San Jose Research Laboratory in San Jose, California developed the LABS/7 operating environment, which with its language Event Driven Language (EDL),

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3906-490: Was the norm and the use of arbitrary subroutine call patterns was rare. The machines were usually deployed for very fixed jobs with a rigidly planned set of software. This often extended to the real-time interrupt latency, using the 4 levels of priority and the carefully crafted software paths to ensure guaranteed latencies. Fortran and a PL/1 subset (PL/7) compilers were available no later than 1976 as larger configurations became more affordable and more complex data processing

3969-454: Was widely adopted by scientists for writing numerically intensive programs, which encouraged compiler writers to produce compilers that could generate faster and more efficient code. The inclusion of a complex number data type in the language made Fortran especially suited to technical applications such as electrical engineering. By 1960, versions of FORTRAN were available for the IBM 709 , 650 , 1620 , and 7090 computers. Significantly,

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