This vector (at 0:0060) has the entry point for the ROM-BASIC interpreter
which is found only on IBM-logoed computers.  Clones do not have BASIC in
ROM and must use a separate program, usually QBASIC or GWBASIC.

If ROM-BIOS could not get a disk to boot, it takes this vector.  This
makes it possible for a ROM-Scan external ROM module to alter this vector
to point to itself, thus giving itself control if the disks fail or are
not present.

- -

INT 18H: ROM-BASIC