As I recall, the part of the system that warns the controller if two ac are on a collision track where not operational this terrible night. and because of that two controllers instead of one where on duty
Yes, and no. One controller was handling two sectors. In addition to the conflict alert being withdrawn, aspects of the communications system were down for maintenance. I believe the two sectors were adjacent, ie, unable to be configured to configured to operate from one workstation.
I was wandering if some controllers used this part of the system as a reminder for them selves of when to issue a climb or descent order to ac
Absolutely not. The system operates by issuing a warning when it calculates the space between the aircraft is about to become inadequate. It's an "on/off" thing. Nobody would operate in this fashion. It's to controllers what TCAS is to pilots, a safety net.