From the Script: SLIDE 7 - Software Growth

Back in the 1960s and 1970s, DOD was developing unique languages for specific purposes. A 1977 study, A Common Programming Language for the Department of Defense - Background, History and Technical Requirements, identified 450 as the minimum probable number of general purpose languages and dialects in use for DOD programs.

Along with this proliferation in programming languages, there was also a steady increase in the size (number of source lines of code) of individual software development programs.

The increased size and complexity of projects is a precursor to the "Software Crisis"