Scope

IO interface bus technologies keep getting faster and more complex in order to provide more bandwidth.

The trend for PC bus technologies has been from a relatively slow asynchronous, parallel bus (ISA bus operating at 12 MHz and 16 bits) to synchronous and faster parallel busses (PCI operating at 66MHz and 64-bits and PCI-X at 133MHz and 64 bits).

Parallel bus technologies have experienced an exponentially increasing bandwidth, but this technology is reaching its practical limitation for offering more bandwidth. Therefore, the trend in PC bus technologies is a move towards new, high-speed serial buses.

PCI Express is an emerging serial bus technology that is expected to dominate the desktop and server market by 2005. There are several issues that make development for PCI Express radically different than development for parallel buses. These differences create a series of new challenges which designers and developers need to consider when entering into this new technology. Some of those are covered in this article.