Overview

Much of the demand for PCs is based on the many available add-on peripheral devices, ranging from common cards such as graphics cards, modems, network cards and sound cards, to technologies including digital cameras, scanners, and external storage devices.

The most common peripheral devices use the PCI, CardBus, USB, and 1394 buses. ISA devices are nearly obsolete. ISA devices were introduced with the first PCs more than 20 years ago, but have become undesirable because of low ISA bus throughput rates, difficult auto-configuration, and lack of power management. The PC 99 System Design Guide recommends eliminating ISA slots, a recommendation followed by many current generation motherboards.

PCI bus devices are the majority of the devices used in PCs today, and receive the main emphasis for new power management features. USB devices are rapidly gaining market share, and will replace the majority of today s slow ISA devices. Popular USB peripherals include keyboards, mouse devices, joysticks, monitors, speakers, scanners, and cameras. The USB specification supports power management and wake up capabilities. USB modems are now capable of signaling to the system that a phone call is incoming, waking the computer to service the call.

The IEEE 1394 bus is a serial interface used by the consumer electronics industry to interface digital cameras or storage devices to personal computers, with data rates planned to reach over 1 Gbps. Additions to the IEEE 1394 standard for power management support and wake up capabilities have been incorporated into the IEEE 1394a-2000 and capabilities...