Power Management; G3 Mechanical Off; G2/S5 Soft Off; G1 Sleeping - NCR RealPOS 70XRT User Manual

1-26 Chapter 1: Overview

Power Management

The BIOS supports the supports the Advanced Configuration and Power Management
Interface (ACPI) 3.0b specification. A key feature of ACPI is that the operating system, not the
BIOS, configures and implements power management. The 7403 terminal supports the Global
system power states defined by ACPI:

G3 Mechanical Off

A computer state that is entered and left by a mechanical means
Example: Turning off the system's power through the movement of a large red switch.
Various government agencies and countries require this operating mode. It is implied by the
entry of this off state through a mechanical means that no electrical current is running through
the circuitry and that it can be worked on without damaging the hardware or endangering
service personnel. The OS must be restarted to return to the Working state. No hardware
context is retained. Except for the real-time clock, power consumption is zero.

G2/S5 Soft Off

A computer state where the computer consumes a minimal amount of power. No user mode or
system mode code is run. This state requires a large latency in order to return to the Working
state. The system's context will not be preserved by the hardware. The system must be
restarted to return to the Working state. It is not safe to disassemble the machine in this state.

G1 Sleeping

A computer state where the computer consumes a small amount of power, user mode threads
are not being executed, and the system appears to be off (from an end user's perspective, the
display is off, and so on). Latency for returning to the Working state varies on the wake
environment selected prior to entry of this state (for example, whether the system should
answer phone calls). Work can be resumed without rebooting the OS because large elements of
system context are saved by the hardware and the rest by system software. It is not safe to
disassemble the machine in this state.

G0 Working

A computer state where the system dispatches user mode (application) threads and they
execute. In this state, peripheral devices (peripherals) are having their power state changed
dynamically. The user can select, through some UI, various performance/power characteristics
of the system to have the software optimize for performance or battery life. The system
responds to external events in real time. It is not safe to disassemble the machine in this state.
ACPI Sleep States (S0 – S5)
Under the G1 sleeping state ACPI defines levels of system sleep state support. The 7403
supports the following sleeping states:
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S0: Normal Powered-On state
S1 (Standby): The S1 sleeping state is a low wake latency sleeping state. In this state, no
system context is lost (CPU or chip set) and hardware maintains all system context.