Abstract: This involves the efficient placement of multiple computers within a given site. The available density of computer systems that may be provided at a location is advantageously increased through various features. By placement of access space to all elements which require periodic attention at the front of each computer, the need for significant space at the rear of a computer is eliminated. Such a computer hardware configuration facilitates back-to-back placement of computers in a rack. Racks filled in this manner may be arranged in rows or otherwise. The back-to-back computers in a rack define an air/gas column that may be air conditioned. By drawing air from this column (or forcing it) through a computer from its back/sides to its front/sides across heat-generating components, highly-effective cooling with certain advantages is achieved.