Abstract: A disk drive test chamber creates an environment for disk drives to be tested with an air circulation system that provides an even flow of air over each drive for equivalence in testing conditions. One method of providing equivalent air circulation is to have turning vanes inside air ducts to divert equal amounts of air over each shelf holding disk drives through identically sized apertures. The second method is to have apertures of varying sizes of 40, 50 and 70 percent opening per square inch in the air ducts to divert equal amounts of air. The temperature is maintained within 1/4.degree. C. of the set point by a controller through a system of heaters, air pumps, air ducts, insulation, vents, a motorized damper and an exhaust fan. The heater generates heat to simulate the actual heat of running conditions of disk drives. The pumps send air up the side air ducts and down the center air duct. The chamber has two safety features to prevent damage to the disk drives from over temperature.