98 Troubleshooting Your System
Checking the Equipment
This section provides troubleshooting procedures for external devices attached
to the system, such as the monitor, keyboard, or mouse. Before you perform any
of the procedures, see "Troubleshooting External Connections" on page99.

Troubleshooting IRQ Assignment Conflicts

Most PCI devices can share an IRQ with another device, but they cannot use an
IRQ simultaneously. To avoid this type of conflict, see the documentation for
each PCI device for specific IRQ requirements. Table4-2 lists the IRQ
assignments.
The USB diskette drive activity
indicator.
See "Troubleshooting a USB Device" on
page102.
The USB CD drive activity indicator. See "Troubleshooting a USB Device" on
page102.
The optical drive activity indicator. See "Troubleshooting an Optical Drive" on
page110.
The hard-drive activity indicator. See "Troubleshooting a Hard Drive" on
page111.
An unfamiliar constant scraping or
grinding sound when you access a
drive.
See
"Getting Help
" on page127
.
Table 4-2. IRQ Assignment Defaults
IRQ Line Assignment
IRQ0 System timer
IRQ1 Keyboard controller
IRQ2 Interrupt controller 1 to enable IRQ8 through IRQ15
IRQ3 Available
IRQ4 Serial port 1 (COM1 and COM3)
IRQ5 Available
Table 4-1. Start-Up Routine Indications (continued)
Look/listen for: Action
book.book Page 98 Thursday, August 30, 2007 3:30 PM