BCM Advanced Research
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The IN440EX supports the ACPI specification and its key elements; The Operating System Directed Power
Management (OSPM). ACPI evolves the existing collection of power management BIOS code, APM APIs, PNP
BIOS APIs, and so on into a well-specified power management and configuration mechanism. It provides support
for an orderly transition from existing (legacy) hardware to ACPI hardware, and it allows for both mechanisms to
exist in a single machine and be used as needed. ACPI evolves the existing motherboard configuration interfaces
to support these advanced architectures in a more robust, and potentially more efficient manner.
OSPM provides a new appliance interface to customers. In particular, it provides for a sleep button. This sleep
button is a “soft” button, which does not turn the machine physically off but signals the OS to go into a ‘soft off’
or sleeping state. ACPI defines two types of these “soft” buttons: one for putting the machine into sleep mode and
one for putting the machine into ‘soft off’ mode.
This gives the OEM two different ways to implement machines: A one or a two-button model. The button on the
one-button model can be used as a power button or a sleep button as determined by user settings. The two-button
model has an easily accessible sleep button and a separate power button. In either model, an override feature that
forces the machine to turn off or to reset without OS consent is also needed to deal with various rare, but
problematic, situations.
ACPI is neither a software nor a hardware specification, although it addresses both software and hardware and
how they must behave. ACPI is actually an interface specification.
