Output Condition of                          
HMK     NMK     Name          Index/Read Data                              

--      --      Full mask     Pulse detection; drive select; ready; seek   
                              complete; (write operation)                   

ON      --      Half mask     Pulse detection; drive select; ready; (write 
                              operation)                                    

--      ON      No mask       Pulse detection; drive select; MTR on; (write 
                              operation)