A capacity and a lifetime of laptop batteries have greatly improved in recent years. However, modern processors devour more energy, than these oldests. An each subsequent laptop generation introduces more amenities which require more energy (e.g. touch screen, built-in speaker etc.). Therefore, the energy management and increasing the battery runtime have became as significant as never. Fortunately, the intelligent policies of the Power Management can achieved a lot.
This solution is called the Advance Configuration and Power Interface (ACPI). It is open standard created by Intel, Microsoft, Toshiba, Phoenix and HP. ACPI enhances the capabilities of power management systems offered by the early termination. ACPI allows operating system to control the amount of energy, which is delivered to individual computer component (e.g. DVD/CD-ROM, hard drive or peripherals devices). It enables off them when they are not used and the save of energy is required.
The most popular part of the standard is typical power management. In this field ACPI introduces two significant improvements. At first, the power management was transferred to operating system. The previously used standard left power consumption issues to BIOS, so operating system had limited access to these settings.
The second important thing is an implementation of the power management principles. Nowadays, ACPI is implemented on mobile devices, domain desktops and servers. Every computer system can be moved into a state of extremely low power consumption. A power supply is disconnected even from the memory device. The system can be quickly placed in a state of full readiness to work with a simple interrupt (using the keypad, real time clock, modem, etc.). These features were common only for laptops until the standard was introduced.