After it is tightened with a snug torque TA, a bolt is tuned by a total turning angle \u03b8S equivalent to the sum of an initial-set turning angle \u03b8A and a corrective additional-turning angle. The host OS and the disk drive operating system can be run on a single processor. All of the user data, application programs, configuration data and the operating systems of the memory-programmable controller are stored on a central computer.