Abstract: A case for mounting slidably a data storage medium in a computer housing includes a metal upper casing part and a cover plate. The upper casing part has a top wall with opposite front and rear edges and opposite lateral edges that interconnect the front and rear edges. The top wall has opposite upper and lower surfaces. The upper surface of the top wall is formed with a plurality of heat dissipating fins. The upper casing part further has two lateral walls with top edges connected to the lateral edges of the top wall. The cover plate has opposite lateral portions connected removably to bottom edges of the lateral walls, and cooperates with the upper casing part to confine a receiving space for receiving the data storage medium therein such that the data storage medium is in contact with the lower surface of the top wall.