> QBasic didn't come until MS-DOS 5, the demo uses MS-DOS 2.
Actually, the demo is PC-DOS 2.0, not MS-DOS 2.0. Notice the disk that's in the emulator's drive. Also, IBM replaced all of Microsoft's copyright notices:
The IBM Personal Computer DOS
Version 2.00 (C)Copyright IBM Corp 1981, 1982 1983
If they're using real disk images, then they must have an actual IBM ROM BASIC in the emulator. PC-DOS BASIC(A) would only run on a true-blue IBM machine, because it called into the ROM BASIC. In contrast, MS-DOS BASIC(A) was implemented entirely in software and would run on any clone.
Actually, the demo is PC-DOS 2.0, not MS-DOS 2.0. Notice the disk that's in the emulator's drive. Also, IBM replaced all of Microsoft's copyright notices:
If they're using real disk images, then they must have an actual IBM ROM BASIC in the emulator. PC-DOS BASIC(A) would only run on a true-blue IBM machine, because it called into the ROM BASIC. In contrast, MS-DOS BASIC(A) was implemented entirely in software and would run on any clone.