Installing and Configuring Hardware Devices

If it seems like it's been a long process to finally get to the actual installation and configuration of your new hardware, take comfort in the fact that you are ready to perform the installation and configuration in a safe manner. All of the prep work that has been done up to this point will help ensure that your Windows 2000 computers function properly and have no hardware incompatibility issues in the future. We will now examine the installation and configuration of hardware in Windows 2000.

Windows 2000 includes many enhancements over previous versions of Windows that greatly simplify device management. Some of these include Advanced Power Management (APM), Advanced Configuration and Power Interface (ACPI), and Plug and Play (PnP).

Plug and Play is a combination of hardware and software that enables a computer to recognize and modify its hardware configuration changes with minimal intervention from the user . The hardware device that you are installing must support the Plug and Play specification to be automatically configured correctly. You will find that some older devices that predate Plug and Play will not be recognized, and thus require that you manually configure resource settings as discussed in the "Configuring Support for Legacy Hardware Devices" later in this chapter.

With Plug and Play, a user can add or remove a device dynamically without manual reconfiguration and without any intricate knowledge of the computer hardware. For example, you can have a laptop in a docking station that contains an Ethernet network connection and later use the same laptop connecting to the network using a built-in modem, without making any configuration changes.

With Plug and Play, you can make changes to the Windows 2000 computer's configuration with the assurance that all devices will work and the computer will reboot correctly after the changes are made. When you install a Plug and Play device, Windows 2000 automatically configures the device to allow it to function properly with the other devices already installed in your computer. Windows 2000 assigns system resources to the device including the following:

• Interrupt request (IRQ) number

• Direct memory access (DMA) channel

• Input/Output (I/O) port address

• Memory address range

Each resource must be unique or the device will not function properly. When the device you are installing is not Plug and Play compatible, Windows 2000 has no way of automatically configuring the device settings. You may have to manually configure the device driver or use the installation program provided by the manufacturer.

If you must manually configure a nonPlug and Play device, the resources assigned become fixed. This reduces the flexibility that Windows 2000 has for allocating resources to other devices. If too many resources are manually configured, Windows 2000 may not be able to install new Plug and Play devices.

Resource settings should be changed only if you are certain that the new settings do not conflict with any other hardware, or if the hardware manufacturer has supplied a specific set of resource settings with the device.

You can configure devices using the Add/Remove Hardware applet in the Control Panel or by using Device Manager, which is located in the Computer Management tool within the Administrative Tools folder in the Control Panel.

With most Plug and Play hardware, you simply connect the device to the computer, and Windows 2000 automatically configures the new settings. Devices and the drivers that control them can support Plug and Play. The possible combinations expand to the following four support scenarios:

• Both the hardware and the driver support Plug and Play Full Plug and Play support is provided in this situation; this is the easiest combination and the most likely to have a successful installation.

• The driver supports Plug and Play, but the hardware does not In this situation, Windows 2000 provides partial Plug and Play support. Windows 2000 does not automatically configure the device drivers, but Plug and Play can manage resource allocations and interface to the power management systems.

• The hardware supports Plug and Play, but the driver does not Windows 2000 does not support Plug and Play in this situation, and the device is treated as a legacy device. This device requires manual configuration of all resource settings.

• Neither the hardware nor the driver support Plug and Play Windows 2000 does not provide any Plug and Play support for this hardware device. All resource settings must be configured manually.

Be sure to understand the difference between Plug and Play and nonPlug and Play compatible hardware. Know how installing each will affect your computer and what Windows 2000 does differently for each type.

For hardware that cannot be automatically identified, the Add/Remove Hardware Wizard provides a method of manually configuring the device resources or manually loading drivers. On the rare occasion that Windows 2000 does not automatically detect your Plug and Play hardware, you can manually initiate the Add/Remove Hardware Wizard if desired. Using the Add/Remove Hardware Wizard is discussed in some detail in the next section.

Using the Add/Remove Hardware Wizard

The Add/Remove Hardware Wizard , located in the Control Panel, is used to initiate automatic hardware installation of both Plug and Play and non-Plug and Play hardware devices. By following the steps that follow, you will initiate a search for a new Plug and Play hardware device. In the absence of any new hardware, you will be presented with a screen to add a new device or troubleshoot an existing device.

1. Click Start, Settings, Control Panel.

2. Double-click the Add/Remove Hardware icon to start the wizard.

3. Click Next to close the Welcome page.

4. Select Add/Troubleshoot a Device and click Next to start the wizard.

Windows 2000 searches for any new Plug and Play hardware and proceeds to install any that is found. If the wizard does not detect any new hardware installed in your computer, it displays a list of installed hardware for you to choose a device for troubleshooting (see Figure 4.5) or installation. The first entry on the hardware list is Add a new device , which provides you with an option to manually initiate the installation of a new hardware device.

Figure 4.5. Installing or troubleshooting hardware.

Configuring Support for Legacy Hardware Devices

If you need to manually install a non-Plug and Play hardware device, you must understand the resources the hardware device expects to use. In most cases, you can readily locate the information about what resources the hardware device requires by reading the provided manufacturer's product documentation. Given this information, you must then determine how to best fit the new hardware device into your existing Windows 2000 system. Table 4.1 describes the resources available in a Windows 2000 computer system that hardware devices use to communicate with the operating system.

Table 4.1. Hardware Device Resources

Resources	Description
Interrupts	Hardware devices use interrupts to indicate to the processor that they need attention. The processor uses this interrupt request (IRQ) as a way of determining which device is looking for service and what type of attention it needs. Windows 2000 provides interrupt numbers 0 through 15 to devices (IRQ 1 is always assigned to the keyboard).
Direct memory access (DMA)	DMAs are channels that allow the hardware device to access memory directly. This allows a device such as a disk drive or floppy drive to write information into memory without interrupting the processor. Windows 2000 provides DMA channels 0 through 7.
Input/Output (I/O) port	I/O ports are areas of memory that the device uses to communicate with Windows 2000. When the processor sees an IRQ request, it checks the I/O port address to retrieve additional information about what the device wants.
Memory	Many hardware devices have onboard memory or can reserve system memory for their use. Any reserved memory is not available for any other device or for Windows 2000.

Windows 2000 Shares Resources

Some resources that devices require must be specifically reserved for a single, specific device. Other resources can be shared between two or more devices, with Windows 2000 dynamically managing resources as required. Windows 2000 works with the computer's BIOS to share resources as follows .

The IRQ uses a Programmable Interrupt Controller (PIC) to request some service for the device. When a request is seen, the current operation is suspended and control is given to the device driver associated with the IRQ number (115). This resource therefore cannot be shared between devices.

The I/O port is a memory block used by the device to communicate the service it is requesting. This is tied to the IRQ number and therefore is dedicated to a device.

The DMA is a direct channel between the device and the computer's memory. The DMA controller supports a number of channels (usually seven) and they are shared between devices (one at a time).

A device memory block is a portion of system memory mapped to the internal memory of the device (usually). This is dedicated to the device and cannot be used by any other process, including Windows 2000.

Determining Available Resources

Once you know what resources your new hardware device requires, you can use Device Manager to display the resources available on your computer. To view the available resources list, double-click the System icon in the Control Panel and click the Hardware tab. Click the Device Manager button and select the Resources by Connection entry in the View menu. Figure 4.6 shows the Device Manager view of resources and their availability.

Figure 4.6. Hardware resources listed by connection in Device Manager.

Changing Resource Assignments

In the event that more than one hardware device in your computer requests the same resources, a conflict will occur. In some cases, these conflicts may only disable the affected devices and prevent you from using them. In other cases, your entire computer may become unstable or even cease to function properly. In any case, you must change one or more resource settings on the Resources tab in the device's Properties information. The following procedure allows you to modify a resource setting:

1. Click Start, Settings, Control Panel.

2. Double-click the System icon and then click the Hardware tab, or right-click the My Computer icon on the Desktop and click Properties from the shortcut menu.

3. Click the Device Manager button.

4. Expand the device type that you wish to change.

5. Right-click the specific device you wish to modify and select Properties from the context menu.

6. Click the Resources tab. If the Resources tab is not present, you will not be able to modify the device's resources.

7. Select the resource setting you wish to modify.

8. Clear the Use automatic settings check box if it is selected. If this box is dimmed, you will not be able to modify the device's resources.

9. Select the resource you wish to modify and then click the Change Setting button.

10. Change your resource settings as required and close the Properties dialog box when done.

After you complete this procedure, Windows 2000 uses the manually configured resource settings for the device. Remember, if this creates a resource conflict, you must solve it yourselfWindows 2000 cannot change any manually configured resource settings.

Changing Resources for NonPlug and Play Devices

Changing the resources assigned to a nonPlug and Play device will not actually change the resources the device uses. This only instructs Windows 2000 what the device configuration is. You must consult the manufacturer's documentation as to what jumpers or software switches to set on the device to conform to the resource assignment you have told Windows 2000 to expect.