Locklin on Science has posted a fascinating piece about cold war computers.
Originally built to coordinate radar and missile defence across the US, the SAGE system could even control airborne “drones”!
This system was built in 1958 and didn’t go offline until 1984 (!!).
The SAGE system had many firsts: it was the first nation wide networked computer system. While it used special leased telephone lines and some of the first modems (at a blistering 1300 baud), it was effectively the internet, long before the internet. It was the first to use CRT screens. The first to use a “touch screen interface” via the use of light pens on the CRT. It was the first to use magnetic core memory. It was the first real time, high availability computer system. It was the first computer system to use time sharing. Many people attribute the genesis of computer programming as a profession to the SAGE system. Modern air traffic control, and computer booking systems of course, descend from the SAGE system.