First met an HP3000 less than five years into its product life. Also conversant with Unix. Have worked on TCP/IP stacks and applications derived from BSD and MIT/CMU-licensed code, now sometimes hacking on freevt3k (github hairyvisionary freevt3k) which is GPLv2 licensed.
@Cube6392 @MudMan Not simply “because they want to”, but because they know it will be treated as an authority (we put so much stuff in) and will (or can be coerced to) give the answers they as paying customers want