CompTIA® A+ 220-701 and 220-702 Cert Guide, Second edition

Appendix D. Hardware Resources

As mentioned in Chapter 2, “PC Anatomy 101,” today’s computers use Plug and Play (PnP) configuration of hardware resources. However, you still need to understand how these hardware resources function. This appendix provides a brief overview of the following hardware resources:

• IRQ

• I/O port address

• DMA channel

• Memory address

The following sections introduce each of these resources and the possible conflicts that you might find in an older system.

IRQs

IRQs, or interrupt requests, are a series of 8 or 16 lines that run between the CPU and both built-in and expansion card devices. Most devices use at least one IRQ. As the name implies, IRQs enable devices to interrupt the CPU to signal for attention when ...