What is the difference between a server rack and server cabinet?

A server rack is a frame into which 19inch rackmount servers, storage and associated networking devices are mounted or ‘rack mounted’. The frame may be 2 or 4-pillar in design. Equipment suitable for a server rack is termed ‘rack mount’ or designed for ‘rack mounting’. A server rack with side panels and a front and rear door assembly can be called a server cabinet. The front door may be solid metal, perforated hex mesh or glass. The rear door is typically solid or perforated hex mesh. The doors and side panels do not just make the server cabinet more secure but also assist air flow management. Server racks and cabinets are defined by their height in ‘U’ where 1U=45mm and their width and depth with typical sizes being 600, 800, 1000 and 1200mm.