Computer system having removable and stackable modules

This invention pertains to computers and other information processing systems and, more particularly, to such a system for receiving one or more stackable and removable modules, wherein each module includes an integrated mechanism that both latches the module's cover to its base and also attaches the module to a computer. An electronic circuits module includes a cover and a base. A lever and cam assembly is rotatably attached to the cover, and the cam includes first and second lobes. The lever and cam assembly is rotatable between first, second and third positions. In the first position, the first lobe can be inserted through an eccentric opening in the base, and then rotated to the second position to lock the cover to the base. In the third position, the module can be inserted into the computer and when the lever and cam assembly is moved back to the second position, the second lobe locks the module in the computer. A mechanism in the computer inhibits the movement of the lever and cam assembly into the first position, thereby preventing the disconnection of the base from the cover when the module is installed in the computer.