Computer numerical control (CNC) is a computer "controller" that reads G-code and M-code commands and drives a machine tool, a powered mechanical device typically used to fabricate components by the selective removal of material. CNC numerically interpolates the points along a cutting tool's toolpath and directs the servomechanisms that translate the data into movement. The operating parameters of the CNC can be altered via the Master Control Unit (MCU) of the machine.A series of CNC machines may be combined into one station, commonly called a "cell", to progressively machine a part requiring several operations. CNC machines today are controlled directly from files created by CAM software packages.G-codes are known as preparatory and movement codes. Depending on the number directly following the G, they can perform an extremely wide range of commands. The G00 code for example, stands for Rapid Traverse, which moves the machine to a given point at top speed. In the industry it is known as the WFO command. The G01 command is the most common command, in which it tells the machine to move in linear interpolation to a given point. The G02/G03 (clockwise/counter clockwise) command is circular interpolation allowing the machine to make near perfect circles with one move.