Programming WCF Services, 2nd Edition

A Brief History of Software Engineering

The first modern computer was an electromechanical, typewriter-sized device developed in Poland in the late 1920s for enciphering messages. The device was later sold to the German Commerce Ministry, and in the 1930s the German military adopted it for enciphering all wireless communication. Today we know it as the Enigma.

Enigma used mechanical rotors to change the route of electrical current flow to a light board in response to a letter key being pressed, resulting in a different letter being output (the ciphered letter). Enigma was not a general-purpose computer: it could only do enciphering and deciphering (which today we call encryption and decryption). If the operator wanted to change the encryption algorithm, he had to physically alter the mechanical structure of the machine by changing the rotors, their order, their initial positions, and the wired plugs that connected the keyboard to the light board. The "program" was therefore coupled in the extreme to the problem it was designed to solve (encryption), and to the mechanical design of the computer.

The late 1940s and the 1950s saw the introduction of the first general-purpose electronic computers for defense purposes. These machines could run code that addressed any problem, not just a single predetermined task. The downside was that the code executed on these computers was in a machine-specific "language" with the program coupled to the hardware itself. Code developed for one machine ...