Rack server

A rack server, comprising:

• a chassis, having a baseplate, a front end, and a rear end;
• a partition board, disposed in the chassis and perpendicular to the baseplate and also perpendicular to the front end and the rear end to divide the chassis into a first chamber and a second chamber, the partition board having a routing port;
• a mother board module, disposed in the first chamber;
• a hard drive module, disposed in the second chamber, comprising:
• a hard drive cage, adapted to be slidably disposed in the second chamber from the front end, the hard drive cage having a first side and a second side parallel to the partition board, and the second side having a hard drive port;
• a hard drive backplane, vertically fixed to the first side of the hard drive cage;
• and
• a plurality of hard drives, pluggably disposed in the hard drive cage and electrically connected to the hard drive backplane, wherein when the hard drive cage is extended out of the chassis, the hard drives are mounted in or withdrawn from the hard drive cage via the hard drive port;
• an extendable/retractable support arm, horizontally disposed above the hard drive cage, with both ends pivoted to the partition board and the hard drive cage, respectively;
• and
• a wire set, arranged inside the support arm, wherein as the support arm is extended/retracted, one end of the wire set is electrically connected to the hard drive backplane and the other end is electrically connected to the mother board module through the routing port.