Some installation software can read the IRQ settings and adjust the IRQ assignment
for its device. However, this is rare, and you should always verify the system resources
assigned by a manufacturer’s installation software and check for resource conflicts.Setting an IRQ with the Windows Device Manager
About the only time you use the Windows Device Manager to configure IRQs is after a
Plug-and-Play device or proprietary installation program has created a conflict by as-
signing a new device to an IRQ already in use by another device.
When you open the Device Manager, its default view lists the PC’s devices by type,
which means the general category of each device, as shown earlier in Figure 13-1. By
clicking the plus sign (+) next to each category, you can expand the device list to show the
devices installed in a category.
If there are any problems with the device, it is indicated with one of three symbols: A yellow circle with a black exclamation point This symbol before a device
name (see Figure 13-6) indicates a possible resource conflict.
A redX This symbol before a device name indicates the device has been
disabled, removed, or that Windows is unable to locate it.
A white circle with a blue lowercasei This symbol before a device name
indicates only that automatic settings are disabled and the device was configured
manually, possibly under software control. There is no problem, necessarily; this
symbol is just a reminder.(^290) PC Hardware: A Beginner’s Guide
Figure 13-5. An illustration of a DIP switch block