Home »
Full Forms »
Computer Acronyms/Abbreviations
What is Advanced Power Management (APM)?
Advanced Power Management (APM): Here, we are going to learn about the advanced power management, its history, power management events, power states, etc.
Submitted by Anushree Goswami, on January 09, 2021
APM: Advanced Power Management
APM is an abbreviation of "Advanced Power Management". It is an API designed and created by Intel and Microsoft. In 1992, it is launched. It allows an operating system functioning an IBM-compatible personal computer to keep up the job with the BIOS, a component of the firmware of computer, to accomplish power management.
- Revision 1.2, which launched in 1996, was the last version of the APM design. ACPI is planned and projected as the descendant of APM.
- APM makes use of a layered method to administer and control devices.
APM-aware applications, which comprise device drivers, converse to an OS-specific APM driver. This driver makes a communication to the APM-aware BIOS, which manages and organizes the hardware. There is the potential to choose out of APM control on a device-by-device foundation, which can be used if a driver yearns to make a communication straightforwardly with a hardware device.
Power Management Events
There are overall 12 power management events, in addition OEM-defined events, that can be directed from the APM BIOS to the operating system.
The APM driver on a standard basis polls for event alteration notifications.
Power Management Events:
| Name |
Code |
| System Standby Request Notification | 0x0001 |
| System Suspend Request Notification | 0x0002 |
| Normal Resume System Notification | 0x0003 |
| Critical Resume System Notification | 0x0004 |
| Battery Low Notification | 0x0005 |
| Power Status Change Notification | 0x0006 |
| Update Time Notification | 0x0007 |
| Critical System Suspend Notification | 0x0008 |
| User System Standby Request Notification | 0x0009 |
| User System Suspend Request Notification | 0x000A |
| System Standby Resume Notification | 0x000B |
| Capabilities Change Notification | 0x000C |
Power management functions:
| Name |
Code |
| APM Installation Check | 0x00 |
| APM Real Mode Interface Connect | 0x01 |
| APM Protected Mode 16-bit Interface Connect | 0x02 |
| APM Protected Mode 32-bit Interface Connect | 0x03 |
| APM Interface Disconnect | 0x04 |
| CPU Idle | 0x05 |
| CPU Busy | 0x06 |
| Set Power State | 0x07 |
| Enable/Disable Power Management | 0x08 |
| Restore APM BIOS Power-On Defaults | 0x09 |
| Get Power Status | 0x0A |
| Get PM Event | 0x0B |
| Get Power State | 0x0C |
| Enable/Disable Device Power Management | 0x0D |
| APM Driver Version | 0x0E |
| Engage/Disengage Power Management | 0x0F |
| Get Capabilities | 0x10 |
| Get/Set/Disable Resume Timer | 0x11 |
| Enable/Disable Resume on Ring Indicator | 0x12 |
| Enable/Disable Timer Based Requests | 0x13 |
| OEM APM Installation Check | 0x80 |
| OEM APM Function | 0x80 |
Power States
The APM design power states comprises system power states and device power states:
System power states
- System Full On
- APM Enabled
- APM Standby
- APM Suspend
- System Off
Device power states
- Device On
- Device Power Managed
- Device Low Power
- Device Off
Reference: Advanced Power Management
Algo tagged in: Dictionary – 'A'