Rack units

This rack diagram example was redesigned from the Wikimedia Commons file: Rackunit.svg. [commons.wikimedia.org/ wiki/ File:Rackunit.svg]
Rack with sample component sizes including an A/ V half-rack unit.
"A rack unit, U or RU as a unit of measure describes the height of equipment[which?] designed to mount in a 19-inch rack or a 23-inch rack. The 19-inch (482.6 mm) or 23-inch (584.2 mm) dimension reflects the width of the equipment mounting-frame in the rack including the frame; the width of the equipment that can be mounted inside the rack is less. One rack unit is 1.75 inches (4.445 cm) high. (This equates to one vershok, an obsolete unit of measurement used officially in Russia until 1924.)
The size of a piece of rack-mounted equipment is frequently described as a number in "U". For example, one rack unit is often referred to as "1U", 2 rack units as "2U" and so on." [Rack unit. Wikipedia]
The example "Rack with sample component sizes including an A/ V half-rack unit" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rack Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.

Server rack diagrams visualize the the rack mounting of computer and network equipment as the drawing of frontal view of the rack with equipment installed. They are used for choosing the equipment or racks to buy, and help to organize equipment on the racks virtually, without the real installation.
"A 19-inch rack is a standardized frame or enclosure for mounting multiple equipment modules. Each module has a front panel that is 19 inches (482.6 mm) wide, including edges or ears that protrude on each side which allow the module to be fastened to the rack frame with screws." [19-inch rack. Wikipedia]
"A rack unit, U or RU is a unit of measure that describes the height of equipment designed to mount in a 19-inch rack or a 23-inch rack. The 19-inch (482.6 mm) or 23-inch (584.2 mm) dimension refers to the width of the equipment mounting frame in the rack including the frame; the width of the equipment that can be mounted inside the rack is less. One rack unit is 1.75 inches (4.445 cm) high.
The size of a piece of rack-mounted equipment is frequently described as a number in "U". For example, one rack unit is often referred to as "1U", 2 rack units as "2U" and so on.
A typical full size rack is 42U, which means it holds just over 6 feet of equipment, and a typical "half-height" rack would be 18-22U, or around 3 feet high." [Rack unit. Wikipedia]
The rack diagram template is included in the Rack Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.