Agree! I don't have an original AT, but that string appears nowhere in the ROM images I found. There is also a fairly accurate web-based emulator, and it doesn'

Agree! I don't have an original AT, but that string appears nowhere in the ROM images I found. There is also a fairly accurate web-based emulator, and it doesn't print this message: https://www.pcjs.org/machines/pcx86/ibm/5170/cga/ https://www.pcjs.org/machines/pcx86/ibm/5170/cga/ I also doubt that IBM had anything to do with the development of Concurrent DOS, which AFAIK was based on earlier multitasking versions of CP/M. It's highly unlikely that IBM worked together with DR on a "secret" 16-bit protected mode OS, only to throw it away and then start over with OS/2, this time in collaboration with Microsoft.