APRIL 6--The PCI Industrial Computer Manufacturers Group (PICMG; Wakefield, MA; www.picmg.org) has approved and released Revision 2.0 of the CompactPCI Hot Swap Specification, PICMG 2.1 R2.0. The 'hot swapping' of components in CompactPCI-based systems allows the removing and replacing of components without having to turn off the power to the system. This capability proves important for applications that require systems to be continuously operational at some level. CompactPCI is an industrial computer platform based on the standard PCI electrical specification in rugged Eurocard packaging using a 2-mm pin and socket connection.
Revision 2.0 includes enhanced software connection architecture, 3.3-V and 66-MHz support, protection against unexpected board extraction, and PCI-X compatibility. 'The revision satisfies a need for clarification of the hot swap state transitions and enhancements to Hot Swap control logic, which has become evident in implementing the initial specification,' says Richard Somes, director of standards at Force Computer Inc. and PCIMG vice president for technology.
The Hot Swap specification provides a framework for designing CompactPCI components, such as boards, backplanes, ICs, and platforms. This framework endows vendors with flexibility to choose the features appropriate for their products and still operate with all other CompactPCI components (Hot Swap and non-Hot Swap).
The basic purpose of the Hot Swap additions to CompactPCI is to permit the orderly insertion and extraction of boards without adversely affecting system operation, the repair of faulty boards, and the reconfiguration of a system. Moreover, Hot Swap offers programmatic access to services, which allows system reconfiguration and fault recovery with no system downtime and minimum operator interaction. As well, it allows the system to isolate faulty boards so that the system can continue operation, possibly with reduced capability, in the event of a failure.