0:480h                   Keyboard Buffer Start Offset Pointer

 Length: 2 bytes

    This word contains the offset of the start of the keyboard buffer.
    This allows you to move the buffer, increase its size, or decrease its
    size. There is one catch, however: The address here is an offset
    starting at address 0:400h. For example, the default 32-byte buffer at
    0:41Eh forces this offset address to be 001Eh. Therefore, if the
    buffer is to be moved to another location, the buffer starting offset
    must be relative to 0:400h.