42U rack with dimensions 600mm x 1000mm typically refers to a floor-standing server rack cabinet, designed to house standard 19-inch rack-mountable equipment. These racks are 42 rack units (42U) tall, with a width of 600mm and a depth of 1000mm. The "U" in 42U refers to rack units, where 1U is equal to 1.75 inches (44.45mm).