The Power Management features are enabled by both the hardware's power-saving capability and the software provided with the Solaris operating environment. The exact nature of the power-saving mode your system goes into depends on your hardware and its compliance with Energy Star. To determine the version of Energy Star to which your system complies, use the prtconf -vp | grep energystar command.
Power Management-capable hardware provides the features discussed in the following sections.
The Energy Star 3.0-compliant SPARCTM hardware reduces power consumption by entering a low-power mode from which devices can resume full operation automatically. This hardware can turn off monitors and frame buffers, spin down disks, and drop the devices' power consumption significantly when they are idle -- all while leaving the system up and running, ready for use, and visible on the network. When a job appears on the system, either through a cron process, or an external demand through a network, the devices and other hardware snap back into full-power mode within seconds.
The earlier, Energy Star 2.0-compliant SPARC hardware does not have the capability of going into a reduced-power mode; after the designated minutes of idleness, the system completely shuts down. The exception to this are the monitors, which do have the capability of going into low-power mode and continuing to operate. Upon restart, the system takes a minute to reboot.
Systems that are noncompliant with Energy Star regulations perform power management for only the monitor; no other devices are power managed.