Abstract: A method and apparatus for controlling fan speed are provided. The method obtains a first PWM value and a second PWM value of the fan based on the temperature of the server component respectively through a PID regulation algorithm and an open-loop control algorithm, and controls the fan speed based on the larger value of the first PWM value and the second PWM value.

Abstract: A method and apparatus for controlling fan speed are provided. The method obtains a first PWM value and a second PWM value of the fan based on the temperature of the server component respectively through a PID regulation algorithm and an open-loop control algorithm, and controls the fan speed based on the larger value of the first PWM value and the second PWM value.

Abstract: An altitude correction method and system for regulating a fan of a server are provided. In the altitude correction method for regulating the fan of the server, a correction parameter calculation formula for a duty cycle of a fan is fitted based on air densities at different altitudes, and the correction parameter obtained according to the correction parameter calculation formula is inputted to a fan regulating program as a variable. The fan regulating program increases or reduces a duty cycle of the fan required for heat dissipation of the fan based on the altitude, and regulates a rotational speed of the fan based on the duty cycle of the fan. An altitude input interface is reserved in the fan regulating program, and an altitude is inputted through the input interface.