What is advanced energy management?

Advanced Power Management (APM) is an interface of programming (API) that allows the operating system to operate an IBM compatible personal computer (PC) to interact with the basic input system (BIOS) to achieve and control energy management. It was created as a joint venture between Intel® and Microsoft® and was made available to the public in 1992. APM was largely replaced by a preliminary management system known as Advanced Configuration and Power Interface (ACPI).

BIOS is a simple program before it is firmly encoded to all personal computers (PC). It controls hardware at the basic level and can communicate with the operating system with any peripheral devices such as a hard drive. The operating system installs APM APM as part of its installation. The API is basically a piece of software that makes it easier to communicate between the operating system and the BIOS.

Whenever a peripheral device such as a monitor or hard disk is connected, a driver must be installed. The driver is SOFTware that allows the device to communicate with the operating system. The driver can be written according to APM specifications so that the power management options can have. An example would be a hard disk that has APM driver; The driver could allow the hard disk to turn off when it is not used.

In advanced energy management, there are basically two states: the state of the system status and the performance of the device. The system status can define five power states for the entire system. Full on and off are the easiest; Full means that the system is turned on and no devices are in energy saving mode and shutdown means that the computer is turned off.

6 APM enabled means that the computer is turned on and APM is available as needed. The standby mode means that most devices are in low power mode, the price for the TRA processing (CPU) is turned off or slowed and the system is stored; In this state, the computer can be started quickly. APMSuspend means that the condition of the system is stored, but most devices are turned off; In this state, the computer takes a longer time to reopen.

The power of the device that allows the equipment to use energy savings, the device is managed by the device power, low power supply and equipment. He and off mean the same as in the system state. In the managed power supply, the device is turned on, but not all functions are available. In the low power supply of the device, the device is not currently active, but the power connection is maintained to start or "wake up" quickly.

The only exception in the Advanced Power Management is a CPU. Only BIOS can control the CPU. The driver, either through a system or through a device, can only contact the BIOS; cannot provide an instruction to turn on. This is to protect the CPU from that it was closed by a poorly written driver.