[JanisErdmanis]

It was worse in the case of early BIOS, which IBM made public in an instruction manual while keeping all relevant rights on distribution. I wonder why they did not publish it with a GPL or AGPL license, where they would keep commercial use to themselves.

[yencabulator]

IBM PC was released in 1981, GPL 2.0 (which was the first version in wide use) in 1991.