IBMBIO.COM

IBMBIO.COM is the filename of the system initialization code and builtin device drivers in many DOS operating systems, and as such part of PC DOS and DR DOS 5.0 and higher (with the exception of DR-DOS 7.06). It serves the same purpose as IO.SYS in MS-DOS, or DRBIOS.SYS in DR DOS 3.31 to 3.41.