Hardware Reference
In-Depth Information
the configuration process, the configuration registers (in flash BIOS) on the cards and the ESCD are
updated with the new configuration data.
PnP Device IDs
All PnP devices must contain a PnP device ID to enable the OS to uniquely recognize the device so it
can load the appropriate driver software. Each device manufacturer is responsible for assigning the
PnP ID for each product and storing it in the hardware.
Each manufacturer of PnP devices must be assigned an industry-unique, three-character vendor ID.
Then the device manufacturer is responsible for assigning a unique product ID to each product model.
After an ID is assigned to a product model, it must not be assigned to any other product model
manufactured by the same company (that is, one that uses the same vendor ID).
Note
For a comprehensive list of PnP device IDs, see the Microsoft Plug and Play ID page at
ACPI
ACPI stands for Advanced Configuration and Power Interface, which defines a standard method for
integrating power management as well as system-configuration features throughout a PC, including the
hardware, OS, and application software. ACPI goes far beyond the previous standard, called
Advanced Power Management (APM)
, which consists mainly of processor, hard disk, and display
control. ACPI controls not only power, but also all the PnP hardware configuration throughout the
system. With ACPI, system configuration (PnP) as well as power management configuration are no
longer controlled via the BIOS Setup; instead, they are controlled entirely within the OS.
The ACPI specification was created by Intel, Microsoft, and Toshiba; version 1.0 was released in
1996. ACPI became one of the major requirements for Microsoft's PC'97 logo certification program,
causing motherboard and BIOS manufacturers to work on integrating ACPI into systems during that
time. Intel integrated ACPI support in chipsets starting in April 1998 with the PIIX4E southbridge,
and Microsoft added ACPI support in Windows starting with the release of Windows 98 (June 25,
1998) as part of what Microsoft called “OnNow” design. By the time Windows 2000 was released
(February 17, 2000), ACPI had universally replaced APM as the primary power management and
control interface on new systems.
ACPI enables the system to automatically turn on and off peripherals (such as optical drives, network
cards, hard disk drives, and printers), as well as external devices connected to the PC (such as
DVRs, televisions, telephones, and stereos). ACPI technology also enables peripherals to turn on or
activate the PC. For example, a DVR can turn on the PC, which could then activate a large-screen
television and high-fidelity sound system.
ACPI enables system designers to implement a range of power management features with various
hardware designs while using the same OS driver. ACPI also uses the PnP BIOS data structures and
takes control over the PnP interface, providing an OS-independent interface for configuration and
control. Microsoft has included support for ACPI in Windows since Windows 98.
During the system setup and boot process, Windows versions supporting ACPI perform a series of
checks and tests to see whether the system hardware and BIOS support ACPI. If support for ACPI is
