3. Designing an I/O bus requires more than a protocol definition and electrical interface specification .While these are two very important aspects of any bus architecture, other issues must also be addressed, such as system design. In the past, a bus had to be made wider for higher performance through higher bandwidth. But the ever-shrinking desktop and server form factors required by IT and consumer markets has made this design methodology both unrealistic and expensive, both in terms of actual costs and power consumption.