PICMG-3 mixes features, extends apps

PICMG-3 mixes features, extends apps
The newest enhancement to the CompactPCI spe-cification, PICMG 3, may provide an answer for a growing range of applications that remain without an effective open-architecture solution. Such applications require a combination of support for ever-faster, power-hungry processor components; built-in availability assurance mechanisms; and fast, scalable intrachassis interconnects.

The specification remains at the time of this writing in its early development stage. The PICMG 3.x architecture builds on some of the basic concepts of CompactPCI by its liberal reuse of existing technologies and adherence to accepted industry practices. The backplane interconnect definition will be structured to support several existing protocols and topologies as well as others expected to emerge in the next five to eight years.

Interconnect links will support redundant connection schemes and allow implementation of a number of standard protocols. Systems can be constructed using Ethernet, Infiniband, 3GIO, Fibre Channel and any number of other interconnect technologies in a switched fabric topology. Applications can thus be integrated using the appropriate switching and data-processing "blades" to meet the needs of a given application. "Blade" is increasingly being used to describe plug-in board and system architectures. Invoking the Swiss army knife, the term refers to multiple utilities that are efficiently packed together in an integrated, accessible configuration.

The interconnect definition will also provide upward bandwidth scalability as devices emerge (10 Gigabit Ethernet and various Infiniband speeds).

Applications requiring very fast, direct blade-to-blade communication will also be supported. The PICMG 3 architecture will provide full-mesh interconnect specifications allow-

ing any blade to communicate directly with any other blade in a system. System architectures will be selected by the designer to provide the best combination of performance, scalability and cost.

As the specification matures, expect products supporting popular protocols to emerge for applications demanding off-the-shelf embedded building blocks.

The PICMG 3 power distribution architecture will support dual dc feeds to each blade in a system with power conversion provided on individual blades. Common dc feed voltages will conform to telco central-office conventions, where -48-volt dc power distribution is common, although exceptions exist and some variations will be accommodated.

"Out-of-band" system management interconnects will also be specified for the backplane. Redundant buses that comply with the Intelligent Platform Management Interface (IPMI) will allow central system management components to monitor, control and report module and system status.

Separate, redundant management power feeds will also allow modules to be queried and identified independently of system power and will control access to the main data interconnects. For example, if it is detected that an incompatible blade (based on embedded electronic ID information) has been installed in a system, that blade may be prevented from "powering up" or connecting to system buses.

Upon completion, the specification may also provide additional features for robust, secure system management.

Ultimately, the PICMG 3 specifications will define an architecture allowing the emergence of a variety of off-the-shelf system building blocks. The resulting capabilities will enable the rapid development of high-performance, highly available, cost-effective embedded systems for use in a wide range of application segments.

Products based on the specification are expected to emerge in late 2002 and early 2003. In the meantime, a broad selection of solutions, based on other open standards such as CompactPCI, are available today with varied combinations of performance and features.