English: IBM’s SAGE is a large semi-automated air defense system from the Cold War era. It would analyze radar data in real-time to identify Soviet bombers. It is the subject of Puzzle 47. You can see about half of the wall of vacuum tubes; the other half did not fit in the frame.

• Weight: 300 tons
• Cost: ~$10 billion

This “company-making” sale was made personally by IBM founder Tom Watson, Sr. Built in 1954, deployed in 1958, obsolete by 1960.

It had a built-in intercom system and cigarette lighters/ashtrays at each console.

The last of 27 installations was shut down in 1983 (in Canada). In the final years, to the chagrin of the USAF, replacement vacuum tubes had to be bought from Soviet bloc countries.

The software development “employed about 20% of the world’s programmers at the peak of the project. When it was complete, the 250,000 lines of code was the most complex piece of software in existence.” (Computer History Museum details)