In 1969 WATBOL, a teaching compiler for COBOL was developed at the University of Waterloo. The compiler was a companion product, built under the design philosophy, of Waterloo`s earlier, widely used WATFOR teaching compiler. Since programs written by undergraduate students were unlikely to be run more than a few times, after they were successfully written and debugged, the efficiency of the program, once compiled was of secondary performance, compared with giving simpler, clearer error messages, and in simplying the steps for the student to compile the program. At that time executing a program through the use of commercial compiler was a three step process. First the Fortran, or COBOL, had to be compiled into assembly language, then the assembly language had to be assembled into binary code; finally the compiled and assembled code had to be linked with previously written libraries of subroutines. WATFOR and WATBOL allowed simple programs, to be compiled, linked, and executed, in a single step.
In 1982 Carol Vogt wrote that 230 other institutions were using WATBOL.
- R.J. Hurdal, W.R. Milne, C.R. Zarnke (1972). "WATBOL" (in English). University of Waterloo Computer Systems Group. Retrieved 2012-12-17. "WATBOL is the University of Waterloo COBOL compiler. It was designed after the manner of WATFOR in that it was to compile COBOL programs quickly and give error diagnostics immediately after the statement that was in error. Also, it was designed to help students debug their own programs without the aid of a tutor."
- "Chronology - 1970s: The Evolution of The University of Waterloo Continues -- 1972" (in English). University of Waterloo. Retrieved 2012-12-17. "In 1969 and 1970, the WATBOL compiler was completed. The WATBOL compiler for the COBOL programming language had speed and error diagnostics similar to the WATFOR compilers for FORTRAN."
- Christopher Brown-Syed (2011). Parents of Invention: The Development of Library Automation Systems in the Late 20th Century: The Development of Library Automation Systems in the Late 20th Century (in English). ABC-CLIO. p. 10. ISBN 9781591587910. Retrieved 2012-12-17. "During the 1970s, the University of Waterloo, located in southern Ontario, Canada, was almost as synonymous with computing as MIT or Berkeley. It had developed extensions to the popular general-purpose Fortran programming language called WATFOR and WATFIV and its own version of the equally popular business computing language COBOL, called WATBOL."
- Harold Alkema, Kenneth McLaughlin (2007). "Unbundling Computing at The University of Waterloo" (in English). University of Waterloo. Archived from the original on 2012-12-18. Retrieved 2012-12-18. "The Department of Computing Services (DCS) newsletter noted that there were 420 institutions using WATFIV, 230 using WATBOL, and 370 using DCS's SCRIPT, all software products constructed by UW."