1970 to 1979: Computers and Software Begin Creating Wealth - The Technical and Social History of Software Engineering - page 168

Monterey, California. (After the conference, Al's paper was republished in my first
book, with the permission of Al and the conference organizers. This first public-
ation of Al's paper in Programming Productivity: Issues for the Eighties by the
IEEE Computer Society Press was the first of many articles and books about func-
tion points.)
In 1979, Dan Bricklin and Bob Frankston introduced the VisiCalc application
for Apple computers, which greatly expanded the use of personal computers for
personal finance and easy mathematical modeling. VisiCalc was also released for
the IBM PC in 1981.
This decade saw the evolution of higher-level languages. Some of the lan-
guages created in this decade include Pascal and Forth in 1970; C, Smalltalk,
and Prolog in 1972; COMAL and EML in 1973; ELAN in 1974; Scheme and
RATFOR in 1975; and SQL in 1978.
These joined COBOL, FORTRAN, and PL/I, and the explosion of languages
was well under way. From this decade forward, new languages appeared almost
every month, and the total number of languages now tops 2,500.
The explosion of programming languages seems to be more of a sociological
phenomenon than a true technical need. The existence of so many programming
languages makes maintenance of legacy applications complex and difficult.
Indeed, the life expectancy of a large application is sometimes longer than the life
of the language used to create it.
Another phenomenon also occurred in this decade, and it is still expanding in
the present decade. Applications began to use multiple languages such as COBOL
and SQL or, more recently, Java and HTML. From my collection of data, an av-
erage software application contains about 2.5 different programming languages. I
have noted that the maximum number of programming languages in a single ap-
plication is 15, and quite a few applications use more than half a dozen.
The plethora of languages is not necessarily beneficial to the industry. Devel-
opment may be aided somewhat, but the task of maintenance and enhancement of
legacy applications written in dead or dying languages has become a major cost
driver for the software industry.
The 1970s also saw the early evolution of structured programming and the
birth of object-oriented programming. The decade witnessed the rapid migration
of computers and software from the scientific and military domains into the busi-
ness domain.