A recording medium having a spare area for defect management, and a method of allocating the spare area. For the first canister purge performed after the engine is started up, a purge valve is driven for a prescribed period at a prescribed purge flow rate. A server blade is removeably connectable to one of the plurality of blade interfaces on the midplane. The at least one elastic element supports the weight of the mixer barrel above the at least one elastic element. Only the first and second lens groups move along the optical axis for zooming.