An industry group has formally christened a faster second-generation version of the PCI technology that's used to plug everything from video cards to InfiniBand adapters into computers. PCI-SIG, the special interest group responsible for PCI Express industry-standard I/O technology, said that the final version of 2.0 specification is available. The improved input/output technology provides higher bandwidth as well as some other features required by the upcoming generations of hardware.

The total capacity of the PCI Express 2.0 bus will be 5Gbps, twice the old standard, and an x16 connector will now be able to achieve transfers as high as 16Gbps. It will be backwards compatible with PCIe 1.1 cards, making it simple for motherboard manufacturers to transition to it in the future. Intel is expected to release its first PCIe 2.0 supporting chipsets, members of the 'Bearlake' family, next quarter.

In addition to the faster signaling rate, PCI-SIG working groups also added several new protocol layer improvements to the PCI Express base 2.0 specification which will allow developers to "design more intelligent devices to optimize platform performance and power consumption while maintaining interoperability, low cost and fast market introduction".

These architecture improvements include:

* Dynamic link speed management allows developers to control the speed at which the link is operating;
* Link bandwidth notification alerts platform software (operating system, device drivers, etc) of changes in link speed and width;
* Capability structure expansion increases control registers to better manage devices, slots and the interconnect;
* Access control services allows for optional controls to manage peer-to-peer transactions;
* Completion timeout control allows developers to define a required disable mechanism for transaction timeouts;
* Function-level reset provides an optional mechanism to reset functions within a multi-function device;
* Power limit redefinition enables slot power limit values to accommodate devices that consume higher power.

PCI Express (PCIe) 2.0 probably will first arrive about a year from now, said Al Yanes, chairman of the PCI SIG.

written by Robert M.