WATFIV (programming language)

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WATFIV, or WATerloo FORTRAN IV, developed at the University of Waterloo, Canada is an implementation of Fortran IV. It is the successor of WATFOR.

WATFIV was in turn succeeded by later versions of WATFOR. WATFIV was used from the late 1960s into the mid 1970's. As FORTRAN IV was slow and costly to debug on an IBM 360 mainframe, much early debugging was done in WATFIV. To accomplish this, it was necessary to write the program as a series of much smaller subroutines because of the limitations of WATFIV. The subroutines were provided with dummy inputs and wrote dummy outputs. Since it was common to have turn around times of ten hours or more, it was advantageous to have several subroutines submitted by the end of the workday. Elapsed time for debugging a complex geophysics program could reach six months. A well-written program running on an IBM 360 could calculate as much in one minute as a person could in perhaps 10,000 hours. Without WATFIV the debugging time would have prevented the successful completion of many specialized programs, and the timesavings might not have occurred for an additional few years.

Because it could complete the three usual steps ("compile-link-go") in just one pass, the WATFIV compiler used much less (scarce and expensive !) machine resources than the usual compilers (FORTRAN IV, FORTHX). It was therefore very popular among students as a computer programming and Fortran learning tool, like WATBOL was to learn COBOL, on IBM 360 and IBM 370.

The WATFOR Story

The design of later versions of WATFOR (WATFIV, WATFOR-77) is rooted in what, to many, are the early days of computing. In the summer of 1965, four undergraduate students of the University of Waterloo, Gus German, Jim Mitchell, Richard Shirley and Robert Zarnke, led by Peter Shantz, developed a FORTRAN compiler for the IBM 7040 computer and called it WATFOR. Its objectives were fast compilation speed and effective error diagnostics at both compile and execution time. It eliminated the need for a separate linking procedure and, as a result, FORTRAN programs which contained no syntax errors were placed into immediate execution. Similar experiments were carried on at the University of Wisconsin (FORGO on the IBM 1620) and at Purdue University (PUFFT on the IBM 7090).

This simple, one-step approach to the processing of programs was revolutionary to many people. Non-experienced programmers could be taught programming at minimal cost in time and computing resources. Experienced programmers quickly saw the benefits of the compiler's good diagnostic capabilities and fast turn-around. Gone were the days of poring through computer memory "dumps" trying to discover the error in a particular program. This early version of WATFOR quickly gained popularity and over 75 institutions installed it on their IBM 7040 systems. The distribution of the compiler was handled by Sandra Bruce (nee Hope).

In 1966, the University decided to replace the 7040 with an IBM 360 computer. This meant that a replacement for the 7040 version of WATFOR had to be created for this new computer. A team of full-time employees and undergraduate students was formed to write an IBM 360 version. The project members, Betty Schmidt, Paul Dirksen, Paul Cress, Lothar K. "Ned" Kesselhut, Bill Kindree and Dereck Meek, who were later joined by Mike Doyle, Rod Milne, Ron Hurdal and Lynn Williams, completed 360 WATFOR in the early part of 1967. The compiler was a great success and many other institutions (universities, colleges, businesses and governmental agencies) started using the WATFOR compiler to meet needs similar to those experienced at the University of Waterloo. The distribution of the software and customer support was carried on by Sandra Ward.

As a result of ideas put forth by the SHARE FORTRAN Committee and others, a new version of WATFOR, called WATFIV, was produced in 1968. WATFIV introduced new features such as CHARACTER variables and direct-access input-output. For their contribution to the advancement of computing through their efforts in the WATFOR/WATFIV projects, Paul Cress and Paul Dirksen were presented with the Grace Murray Hopper Award by the Association for Computing Machinery (ACM) in 1972. The WATFIV compiler was included in the DATAPRO Honour Roll for 1975 and 1976, and has received honourable mention in other years.

Along the way a number of people were involved with the maintenance and enhancement of WATFOR and WATFIV. They included Bernie Murphy, Martin Wiseman and Yvonne Johnson.

In 1974, a compiler with characteristics similar to the IBM implementation was created for the Digital Equipment Corporation PDP11 computer and called WATFOR-11. The team members, Jack Schueler, Jim Welch and Terry Wilkinson, were later joined by Ian McPhee who had been busy adding new control statements to the WATFIV compiler to facilitate Structured Programming (SP). These new statements included the block IF (later included in the ANSI X3.9-1978 language standard), WHILE, UNTIL, etc. A new version of WATFIV, called WATFIV-S, was announced in 1974 and a few months later, WATFOR-11S (the "S" indicating the new SP features) was also announced. The original SP features were later enhanced with additional statements by Bruce Hay in WATFIV-S (1980) and by Jack Schueler in WATFOR-11S (1981).

WATFIV and WATFOR-11 compilers were widely used and earned a worldwide reputation. Universities and corporations on every continent used these compilers and a number of other Waterloo and WATCOM software products which have been developed in the WATFOR tradition. At one point, more than 3,000 mini and mainframe computer licenses and over 100,000 microcomputer licenses were held worldwide for this family of software products.

A very important contributor to this success story was Professor J. Wesley Graham. Over the years, he provided leadership and inspiration to all of those involved in the various projects. Although many of the people mentioned above had departed the university, he managed to entice a number of dedicated people to stay in Waterloo. Continuity of personnel resulted in continuity of product support and maintenance. The ongoing service to WATFOR/WATFIV users over the years was instrumental to the continued popularity of the software.

During the 1970s, the ANSI X3J3 subcommittee (the FORTRAN language standard group) developed a new language standard which was officially approved in April, 1978. This standard, designated FORTRAN 77, introduced many new statements into the language. In fact, the previous language standard FORTRAN 66 was a very small document and described, what was in effect, a subset of most implementations of FORTRAN. For example, the WATFIV and WATFOR-11 implementations were based upon the IBM definition of FORTRAN-IV.

It became obvious, as programmers began to use the features of FORTRAN 77, that a new compiler was required which combined the desirable attributes of the WATFIV compiler and supported the new language standard. In January 1983, a project to develop a FORTRAN 77 compiler was started at WATCOM Systems Inc. Under the leadership of Jack Schueler, a team of full-time WATCOM employees and undergraduate students from the University of Waterloo's Co-operative Computer Science program became involved in the creation of the WATFOR-77 compiler. The major work was done by Geno Coschi, Fred Crigger, John Dahms, Jim Graham, Jack Schueler, Anthony Scian and Paul Van Oorschot. They were assisted by Rod Cremasco, John McCormick, David McKee and Brian Stecher. Many of the team members from former WATFOR/WATFIV compiler projects provided valuable input. These included Bruce Hay, Ian McPhee, Sandra Ward, Jim Welch and Terry Wilkinson.

Unlike the previous WATFOR compilers, a significant portion of WATFOR-77 was to be written in a portable systems language. It was hoped that this approach would make the implementation of the compiler on various computer systems somewhat easier. This just wasn't feasible for earlier WATFOR compilers which were written entirely in machine (assembly) language.

They decided that two components of the compiler would not be portable. The code generator would translate FORTRAN statements into native computer instructions and store them in memory. The first version of WATFOR-77 would generate instructions for the IBM 370 computer architecture. As well, most of the execution-time support (undefined variable checking, subscript evaluation, intrinsic routines like SIN, ATAN2, etc.) would be written in assembly language. It was felt that this approach would ensure optimal performance of the executable code.

In September 1984, the first version of WATFOR-77 was installed at the University of Waterloo for use by members of the Department of Computing Services. It was an implementation for the IBM 370 series of computers running the VM/SP CMS operating system.

A few months earlier, in May 1984, a project was started to implement the WATFOR-77 compiler on the IBM Personal Computer. The members of this project included Geno Coschi, Fred Crigger, Tim Galvin, Athos Kasapi, Jack Schueler, Terry Skomorowski and Brian Stecher.

In April 1985, this second version of WATFOR-77 was installed at the University of Waterloo for use by students of the Faculty of Engineering. The compiler could run on a 256K IBM Personal Computer using IBM PC DOS 2.0 and did not require special floating-point hardware. The personal computers were connected to the JANET network. Subsequently, the compiler was installed on the WatStar personal computer network.

In the fall of 1985, a Japanese version of WATFOR-77 was delivered to IBM Japan for the IBM JX Personal Computer. This version produced Japanese language error messages and supported the Kanji, Hiragana and Katakana character sets for variable names and character strings. To support the use of the JX version of WATFOR-77, the WATFOR-77 Language Reference manual and User's Guide were translated into Japanese.

During the summer of 1986, the IBM PC version of WATFOR-77 was adapted to run on the Unisys ICON, an iAPX-186 based microcomputer system that ran the QNX operating system. Since the UNIX-like QNX was quite different from IBM PC DOS, parts of the run-time system were rewritten. This implementation of WATFOR-77 was made available in September 1986.

During the summer of 1985, a project was started to adapt WATFOR-77 to the Digital VAX computer series running the VMS operating system. The members of this project included Geno Coschi, Marc Ouellette, Jack Schueler and Terry Skomorowski. This implementation was made available in March 1987.

In the spring of 1988, a version of WATFOR-77 was adapted to the Japanese IBM PS/55 family of personal computers. As on the IBM JX Personal Computer, this version produced Japanese language error messages and supported the Kanji, Hiragana and Katakana character sets for variable names and character strings.

Also, in the spring of 1988, a new project was begun to develop an optimizing FORTRAN 77 compiler. This compiler was based on the work done in the WATFOR-77 and WATCOM C compiler projects. The code generator used was the same one that was employed by the WATCOM C compiler. At the time, the machine code produced by the WATCOM C compiler was superior to other C compilers. It was realized that this achievement could be repeated in a FORTRAN optimizing compiler. The FORTRAN 77 optimizing compiler was first shipped in mid 1990.

In October 1990, the 25th anniversary of WATFOR was celebrated. All those who were involved in the development of the various WATFOR compilers were invited to the University of Waterloo for a reunion.

In the spring of 1992, a version of WATFOR-77 was adapted to the NEC PC-9801 family of personal computers. This version was similar to the IBM PS/55 version but was modified to accommodate architectural differences between the IBM PS/55 and the NEC PC-9801.

In January 1992, the development of a 32-bit version of WATFOR-77 for 386- and 486-based personal computers was begun. The first version of the 32-bit WATFOR-77 was shipped in the fall of 1992.

Since then no new WATFOR-like FORTRAN compilers have been developed.

However, as late as 1995, classes for programming in WATFIV were still being held at the University of Mississippi, in Oxford, MS. Led by Professor Charles H. (Chuckie) Franke, fully creditable, 3-semester-hour courses were offered to students who wanted some greenscreen time with an obsolescent FORTRAN compiler.

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