When the first digital computers appeared in the early 1940s, the instructions to make them operate were wired into the machine. Practitioners quickly realized that this design was not flexible and came up with the "stored program architecture" or von Neumann architecture. Thus the division between "hardware" and "software" began with abstraction being used to deal with the complexity of computing.
Programming languages started to appear in the early 1950s and this was also another major step in abstraction. Major languages such as Fortran, ALGOL, PL/I, and COBOL were released in the late 1950 and 1960s to deal with scientific, algorithmic, and business problems respectively. David Parnas introduced the key concept of modularity and information hiding in 1972 to help programmers deal with the ever-increasing complexity of software systems.
The origins of the term "software engineering" have been attributed to various sources.

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