DOS 1.0 used forward slashes for arguments because CP/M did the same. DOS 1.0 was almost an exact copy of CP/M, changing only a few small things, which is why

DOS 1.0 used forward slashes for arguments because CP/M did the same. DOS 1.0 was almost an exact copy of CP/M, changing only a few small things, which is why it didn't support directories, either. DOS 2 needed to be compatible with DOS 1, and DOS 1 needed to be able to run CP/M programs in order to capture the business it was gaining at that point, so DOS 2 kept what DOS 1 had, and so on. all the way up to Windows 11 today. The backslash didn't come from CP/M, as I said. it came because they needed a directory separator for DOS 2, and being visually similar to the UNIX directory separator character (a simple diagonal line), the backslash was chosen. so, as I said earlier (very poorly, looking back), the backslash was chosen because of CP/M, but was not copied from it.