public @dtbl
        extrn sd0,sd1,sd2,sd3
        extrn sd4,sd5,sd6,sd7

        cseg

@dtbl   dw sd0,sd1,sd2,sd3      ; drives A-D
        dw sd4,sd5,sd6,sd7      ; drives E-H
        dw 0,0,0,0              ; drives I-L
        dw 0,0,0,0              ; drives M-P

        end