The IDPA Classifier (NOT "qualifier") is 90 shots in three stages from 5 to 20 yards. Some shot on the move, some shot from cover, some shot weak handed, some shot after a reload. The time frame is however long it takes you; your score is your time from the start signal to the last shot of each individual string within a stage, plus time for off-center hits and Procedural Errors.
Look in the IDPA rules for details:
http://www.idpa.com/classify.asp