Power Management Controller. Part I

In the mid-1990-s all computers were produced according to the Energy Star standard which indicated the availability of the energy saving functions. This standard has been jointly developed by Microsoft and Intel Companies and its logo is on all brand computers, monitors, printers and other peripheral internal and external devices which meet the set values on power saving. At around the same time, the parameters of power management “Advanced Power Management” (APM) were added to BIOS. These parameters offered a broad range of possibilities that, unfortunately, in most cases have not been in use because of poor-quality processing in these operating systems.

The further development of APM was “Advanced Configuration and Power Interface” (ACPI) that has been jointly developed by Intel, Toshiba and Microsoft Companies. This standard had been integrated into Windows98. As a result, we have a manager which not only controls the power but enables to control the entire system. Here are some opportunities of ACPI standard:

  • Monitoring the system Events. A system that uses this standard enables to respond flexibly to changes in power consumption or the temperature of a processor or an air inside the case, to control the turning of system devices on/off.
  • System Power Management. A system is automatically or forcibly able to access the lower levels of power consumption until a complete power disconnection with the further restoration of working capacity.
  • Processor Power Management. A system is automatically able to switch off a processor during the down time. This has favorable impacts on the processor’s resource productivity.
  • Device Power Management. A system is able to control and reallocate the modes of power consumption depending on the requirements of a system, the software and a user.
  • Thermal Management. A system enables to monitor the temperature in different devices (in most cases, a processor or a system unit) using special sensors.