Comment by skissane

> Some industrial devices I have worked on in the past turned out to actually be ARM based, running Linux, but the software went a long way to convincingly fake old Windows style UI or emulate a DOS prompt. I was once tasked to extend such a UI library to faithfully reproduce Windows 98 style color gradient borders.

IBM mainframes have an embedded PC (the "Support Element") used to manage the hardware configuration and diagnostics. Originally, it ran OS/2. In 2005, IBM replaced it with Linux–running a UI which looked like OS/2. (At some point more recently, they refreshed the visual look so it doesn't look like OS/2 any more, although I'm not sure when they did that.)