1970 to 1979: Computers and Software Begin Creating Wealth - The Technical and Social History of Software Engineering - page 153

sponse to the expansion of software, the increase in size of software systems, and
the mounting numbers of quality problems that began to attract attention.
Brooks's classic book The Mythical Man-Month dealt with an issue that first
became important during this decade and that still remains important. The issue is
that as software applications began to get large, software bugs or defects and the
volumes of software paperwork increased at a faster rate than size itself measured
using either function points or lines of code. The IBM operating system discussed
in the topic, the S/360, was the first IBM application to top 1,000,000 lines of
code, or roughly 10,000 function points.
IBM had not planned on keeping the S/360 for more than about five years. In
the middle of the 1970s, IBM was working on a new operating system to be called
Future System , or FS for short. This would have been at least ten times larger than
the S/360. However, it was recognized that even IBM would have trouble building
such a massive system to meet the planned schedule and making it reliable enough
to meet IBM's stringent quality standards.
While doing some work on the IBM Future System, I became interested in the
size of the requirements and specifications. When they were scaled up from the
size of similar materials for the S/360, the number of pages in total would take 40
years for an IBM employee to read. One of the endemic problems of a big system
is that the volume of paperwork grows faster than the code size.
Numerous Fragmented Software Subcategories
The decade saw the overall software industry begin to fragment into a number of
subindustries, each of which would become large and profitable in its own right.
Younger readers probably take these categories for granted because they have
used computer-controlled devices since early childhood. Older readers born before
World War II have seen the creation of the entire gamut of applications discussed
here because none of them existed until the 1950s and many did not exist until the
1970s or later.
The following subsections provide short summaries of these software categor-
ies. These are some but not all of the major forms of software that emerged during
the 1970s.