[projektfu]

I guess it got its name from the contrast to older practices. Software projects used to divide parts up considerably as part of system design and give them to individuals. Separate compilation, like in Ada, was supposed to allow compiling to interfaces without having the implementation available. After the detailed design and implementation was finished, the parts could theoretically be integrated during a period called "integration hell".

I remember the MCSD docs were promoting a "Daily build and smoke test". This was a huge difference in that they promoted at least making sure that thev whole system could be built in some state every day.

CI really appeared in the late 90s when someone had the idea that integration tests could be run for small gains in functionality. Then the software could be automatically tested on every incremental change. I credit C3/XP for popularizing the practice but I'm not a historian. Possibly someone was already at it before.