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Managing Hardware on Portable Computers
The Plug and Play support in Windows 2000 allows the operating system to configure devices quickly without requiring you to restart the computer. As a consequence, you can add or remove a device from the computer while it is running; and Windows 2000 allocates resources, loads the appropriate device drivers, and enables the device. Full Plug and Play support is useful for portable computers because the device configuration frequently changes to accommodate the user's environment (docked or undocked) and the user's needs (work remotely online, or work offline). For portable computers that are ACPI enabled, Plug and Play makes the following functionality possible:
Hot docking and undocking.Hot swapping of integrated drive electronics (IDE) devices in device bays, such as hard drives, floppy drives, and CD-ROM drives.Automatic creation of docked and undocked hardware profiles.Dynamic configuration of PC Cards and CardBus cards without restarting the computer.
This section discusses the functionality presented in the preceding list and also hardware management issues such as surprise removal. For more information about installing, configuring, and troubleshooting devices, see "Device Management" in this book. For more information about hardware management, including power management and Plug and Play, see "Hardware Management" in this book.
NOTE
Full Plug and Play support is possible only if both the device and the device drivers support Plug and Play and the computer is ACPI-based. For computers that are not ACPI-based, Plug and Play recognizes hardware changes, but only after the computer is restarted.
Hardware Profiles
Windows 2000 uses hardware profiles to determine what drivers to load when the system hardware changes. Hardware profiles are an important feature for portable computers that use a docking station. Windows 2000 uses one hardware profile to load drivers when the portable computer is docked and another when the computer is undocked. Windows 2000 automatically creates these two hardware profiles for portable computers.The profiles are created when Windows 2000 queries the BIOS for a dock serial ID and then assigns names for the docked and undocked configurations. By default, the docked and undocked profiles are called Undocked Profile and Docked Profile. If a portable computer is fully Plug and Play–compliant, you do not need to use any other hardware profiles except these. Also, you do not have to designate which profile to use when the computer starts. The computer is aware of the docked or undocked state and chooses the appropriate profile.If a portable computer is not fully Plug and Play–compliant, you might need to create a new hardware profile. You can then configure the profile by enabling and disabling devices.To create a new hardware profile
From the Start menu, point to Settings, and then click Control Panel.Double-click System.On the Hardware tab, click Hardware Profiles.Under Available hardware profiles, click a profile, and then click Copy.In the Copy Profile dialog box, enter a name for the new profile.
To configure a hardware profile
From the Start menu, point to Settings, and then click Control Panel.Double-click System.On the Hardware tab, click Device Manager.Double-click the device you want to add or remove from the hardware profile, and then under Device usage select the setting you want.
NOTE
Do not reconfigure the Docked Profile or the Undocked Profile if your system is Plug and Play-compliant.
Dynamic Device Configuration
Dynamic device configuration allows portable computer users to add or remove PC Cards and IDE devices without restarting the computer. However, this is possible only if the device and the device drivers support Plug and Play and the computer is ACPI-enabled. For computers that are not ACPI-enabled, Plug and Play support recognizes hardware changes, but only after the computer is restarted.
PC Card Devices and CardBus Devices
In Windows 2000, Plug and Play support for the PC Card socket is enabled for CardBus devices and PC Card devices. To take advantage of Plug and Play, a PC Card device or a CardBus device must contain the information that Windows 2000 can use to create a unique device ID for the card. This is called the card information structure (CIS). If a CIS is present, Windows 2000 configures the device, loads the appropriate drivers, and enables the device without requiring you to restart the computer. If the computer is not ACPI-based and the device and its drivers are Plug and Play–compliant, this happens after you restart the computer.You can implement PC Card device drivers and CardBus device drivers in three possible scenarios:
A standard Plug and Play device driver for PC Card (the preferred driver) can handle dynamic configuration and removal and receive configuration information from the operating system without knowledge of the card in the PC Card bus. The recommended choices are NDIS version 5.x drivers for network adapters and miniport drivers for Small Computer System Interface (SCSI) cards. Generic Windows 2000 device drivers are supported automatically for such devices as modems and disk drives. if the card contains complete configuration information, the operating system initializes the device and passes configuration information to the driver. Manufacturer-supplied drivers are required for device classes that Windows 2000 does not natively support.
If Windows 2000 includes supporting drivers for the PC Card device or CardBus device, installation and configuration should be automatic. Otherwise, you might be prompted for the device drivers. Also, device drivers (saved in .cab files) are installed on the hard drive during setup. You do not need the Windows 2000 operating system CD to install drivers that are included with Windows 2000.Although Windows 2000 dynamically configures PC Card devices and CardBus devices, notify Windows 2000 before you remove these types of devices from the computer. This notification, which tells Windows 2000 to stop the device, ensures that your system remains stable. You can stop devices by using Add/Remove Hardware in Control Panel.To stop a PC Card or CardBus device
From the Start menu, point to Settings, and then click Control Panel.Double-click Add/Remove Hardware, and then click Next.Click Uninstall/Unplug a device, and then click Next.Click Unplug/Eject a device, and then click Next.Select the device you want to remove, and then click Next.Confirm that you want to remove the device by clicking Next.Click Finish.
You can also stop a device by clicking the Unplug/Eject icon on the taskbar. The icon appears by default whenever a PC Card device or CardBus device is installed. You can hide the icon by configuring the properties of the icon.To hide the Unplug/Eject icon in the taskbar
Right-click the PC Card icon in the taskbar, and then click Properties.In the Unplug or Eject Hardware dialog box, clear the the Show Unplug/Eject icon check box on the taskbar.
IDE Devices
Windows 2000 supports hot swapping of IDE devices such as floppy drives, CD-ROM drives, and hard drives. As with PC Card devices, this is only available if the computer is ACPI-enabled. Non-ACPI-enabled computers can swap IDE devices, but to do so requires restarting the computer. Also, you should stop IDE devices by clicking the Unplug/Eject icon or Add/Remove Hardware in Control Panel before you swap them or remove them.
IMPORTANT
Some ACPI-enabled machines may not be fully ACPI compliant or support the ability to hot swap mass storage IDE-based devices without rebooting. In these cases, removing an IDE-based device without first shutting down the computer could physically damage the device.
Docking and Undocking
There are three methods of docking and undocking a portable computer: cold, warm, and hot. A cold dock or undock means that the computer has been shut down before it is inserted into or removed from the docking station. A warm dock or undock means the computer has been put into standby mode before it is inserted into or removed from the docking station. A hot dock or undock means that the computer is running, with or without programs and documents open, when it is inserted into or removed from the docking station.
CAUTION
Do not undock portable computers while they are in hibernate mode. Hibernate mode saves the system's state to a file, including the current hardware configuration. When a computer resumes from hibernate mode and the actual hardware configuration is different from the hardware configuration at the time it went into hibernate mode, errors result and the system might behave erratically.
Hot Docking and Undocking
There is only one way to perform a hot dock. But there are two ways a user can perform a hot undock—by using the Eject PC command in the Windows 2000 user interface, or by physically removing the portable computer from the docking station using whatever mechanism the docking station provides. The latter method is not recommended.
NOTETo perform a hot dock
Hot docking and hot undocking can only be performed on computers that are ACPI-enabled.
While the computer is running, insert it into the docking station.
To perform a hot undock
From the Start menu, click Eject PC, and then eject or remove the computer from the docking station. The Eject PC command appears only if a computer is ACPI-enabled.
You can also use Group Policy to disable hot docking, in which case the Eject PC command does not appear, not even on ACPI-based computers. For more information about using Group Policy, see "Undocking Portable Computers" later in this chapter.
Warm Docking and Undocking
Windows 2000 adheres to the ACPI specification in terms of warm docking and undocking. If a portable computer supports warm undocking, the Eject PC command instructs Windows 2000 to unload the device drivers for the devices in the docking station and then put the computer into standby mode. After the computer enters standby mode, the user can undock the computer. The original equipment manufacturer (OEM) can help you determine whether the BIOS in a portable computer supports warm undocking.
IMPORTANTSome manufacturers use warm undocking as an alternative to hot undocking if low battery power is detected. In these cases, when a user attempts a hot undock using the Eject PC command and the system detects that there is insufficient battery power to maintain the system after it undocks, Windows 2000 checks the BIOS to see if it supports warm undocking. If it does, the device drivers for the devices in the docking station are unloaded and the computer is put into standby mode.There is only one way to perform a warm dock.To perform a warm dock
You cannot manually put the computer into standby mode or hibernate mode and then undock. This is because Windows 2000 does not unload the device drivers for devices in the docking station when standby mode or hibernate mode are activated manually or through a timer event.
While the computer is in standby mode, insert it in the docking station.
Likewise, there is only one way to perform a warm undock.To perform a warm undock
From the Start menu, click Eject PC.After the computer enters standby mode, remove or eject the computer from the docking station.
NOTE
Warm undocking can only be performed on computers that are ACPI-enabled and that have a BIOS that supports warm undocking functionality.
Cold Docking and Undocking
Cold docking means that the computer is completely shut down before it is docked or undocked. Cold docking and undocking should be used if you have a non-ACPI-based computer, including an APM-based computer. Also, when you shut down the computer before a cold dock or undock, you must use the Shut down command, not the Hibernate command or Stand by command.To perform a cold dock
While the computer is shut down, insert it into the docking station.
To perform a cold undock
While the computer is shut down, remove or eject it from the docking station.
Surprise Removals
A surprise removal is when a PC Card or CardBus device is removed from a portable computer while the computer is running and Windows 2000 is not notified before the device is removed. ACPI-based computers can usually recover from surprise removals because ACPI allows Windows 2000 to dynamically reconfigure hardware. However, surprise removals are not recommended. Instead, stop a device, and then remove it.To stop a device
Double-click the Unplug/Eject icon on the taskbar.In the Unplug or Eject Hardware dialog box, select the device you want to stop, and then click Stop.Remove, eject, or unplug the device from the computer.
Surprise removal can also occur when a computer is running and someone undocks it without first using the Eject PC command. Or it can occur when someone puts a portable computer into standby mode or hibernate mode and then physically removes the computer from the docking station without first shutting down the computer.
WARNING
Removing a portable computer without using the Eject PC command is not supported in Windows 2000 and can result in hardware damage and data loss. To avoid this, use the Eject PC command to perform a hot undock, or shut down the system and perform a cold undock. Undocking a portable computer while it is in standby mode or hibernate mode is also not supported in Windows 2000. Although doing this might not incur hardware damage, it is likely to result in data loss and system instability. To avoid this situation, use the hot undock or cold undock procedures described in the preceding sections.
