any difference in timestamps indicates inconsistency of the databases the library manager with the most recently updated database then becomes u201c active u201d and the other becomes u201c backup u201d when the timestamps match the roles are determined by a preference stored in each library manager this preference is stored in each library manager in the microcode such preference might be then overridden by an environment variable or by the user fig4 a illustrates the effect of this preference on active status with simultaneous timecode stamps in fig4 a server tp is started simultaneously and the sna allocate communications are initiated to one another simultaneously responsive to the sna allocate signals the sna receive_allocates signals are returned simultaneously followed by simultaneous initialization request signals substantially as shown because the requests are simultaneous both library managers a and b respond by rejecting the initialization requests from the other at this point a pseudorandom wait time interval is established in both managers because this wait interval is selected randomly to be between 0 and 30 seconds one of the library managers must wait longer than the other in fig4 a the active and backup roles are determined by the timestamp information in the request and response in the case of.