First of all, according to their own needs, the standard cabinet for 42U, which is the international common specifications, 1U = 44.45mm, the thickness of 4.445cm as the basic unit. 1U is 4.445cm, 2U is 1U 2 times 8.89cm, that is to say, the so-called "1U server", the standard The cabinet can store 18 1U servers, 42U is 2m high, 0.6m wide and 0.8m deep server cabinet, or it may be 2m, 0.6m wide and 0.96m deep server cabinet.