ACP, One of the Oldest Open Source Apps
Esther Schindler writes "The Airline Control Program (ACP), introduced by IBM around 1967, predated the term 'open source' by decades. But you may be surprised by how much of its development resembles the FOSS movement today. The ITWorld.com article An Abbreviated History of ACP, One of the Oldest Open Source Applications describes what made it special."
Agreed - DOS had nothing to do with it.
But dont forget VM, the first virtualization OS that I know of - and I dont know much about non-ibm computers of that time - but it came out of the necessity of the people who started running DOS while waiting for OS to get finished, and then couldnt afford 2 computers to run simultaneously while they migrated from DOS to OS. and of course, it is now z/VM - and more often used as part of the hardware microcode providing hardware partitioning.
All early IBM OSs had the source freely available, DOS, OS and VM. I do not think the license restricted redistribution either, since it was available freely from the vendor. The OSs did not become 'licensed' until IBM got tired of supplying the OS for competing hardware - Amdal - and in my mind you can blame the entire software licensing mess of today on a hardware vendor too lazy to write (significant portions of) its own software, and mostly interested in hardware only profits (wow, sounds vaguely familiar even today).
Anyhow, I was one of those geeky systems programmer guys, making operating system level changes to source code - I never saw it as open source movement though, just something we did to make the OS better fit our needs. 90% of what we needed could be done with vendor supplied 'hooks' that we shimmed in our 'exits' at. I wish more of that kind of thing still existed in all OSs.
slashdot troll = you make a compelling argument I do not like the implications of.
"open source" was the norm for almost all programs in the 1960s. Spacewar was certainly as open as ATP, or more so by most definitions (no commercial claims at all), and was released in 1962. Source code for earlier games, like Nim and Wumpus, were widely available as well.
This author appears to be committing the sin of omission, conflating his IBM-centric experience with the wider world.
Maury