'C' Command (V0011.0000) : Servo Diag Sub Cmds

'R' Command (V0011.0000) : Read Current Servo Destination

'S' Command (V0011.0000) : Seek to Logical Cylinder and Head

'U' Command (V0011.0000) : Spin Up Drive

'Z' Command (V0011.0000) : Spin Down Drive

'd' Command (V0001.0000) : Head Smash Test