PCI Express and Thunderbolt

Abstract

PCI (Peripheral Component Interconnect) is a high-speed bus developed by Intel, in the early nineties, to replace various older and slower bus technologies such as EISA, ISA, MCA, and VESA. The term PCI is often used to describe the family of technologies based on the original PCI specification. Throughout this chapter, when we refer to PCI, we refer to commonalities found in the PCI-based technologies; namely, PCI Express, Thunderbolt, and to a lesser extent ExpressCard. Most people associate PCI with expansion boards plugged into a computer, but it is worth noting that PCI is fundamental to many computer systems—even those without PCI slots, such as iMacs— that have internal PCI buses that connect the CPU to USB, Firewire, and SATA controllers. Recent PCI-based advancements (like Thunderbolt) allow the PCI bus to be extended outside of the computer, much in the same way as USB and Firewire.