A power-management design initiative from Microsoft that combines innovation in PC hardware and software to produce a computer that is always on but appears to be off and that responds immediately when a user or application makes a request.
For example, an incoming telephone call could wake the computer and start a TAPI-enabled application. OnNow is designed to make personal computers function like appliances in the sense that they respond instantly to user action instead of requiring a warm-up period or boot process.
OnNow is based on the Advanced Configuration and Power Interface (ACPI) specification developed by Intel, Microsoft, and Toshiba.
Microsoft Windows 98 directs its power-management functions through the OnNow system. Instead of having the system BIOS control the power state of the system devices and peripherals, OnNow lets the operating system control it.
The operating system can place various devices in a sleep state to conserve power and wake them to full power instantly when a user or application issues a request.
For OnNow to function as designed, the system must have peripherals and applications that support OnNow power-management functions and the system BIOS must support ACPI.