Rack server mounting systems have stayed the same, but as technology continues to improve, the servers mounted within the rack have changed greatly. The rack can mount several types of hardware inside it. These are known as rack-mount, rack-mount instrument, rack mounted system, rack mount chasses, sub-rack rack mountable, or a shelf.
Racks are used for many types of businesses, but the general idea is to have several computers within one. This creates a more powerful machine and saves floor space.