SAN MATEO (03/17/2000) - Driven by the notion that "Processor megahertz get all the glory, but I/O bandwidth wins the game," the PCI-X Special Interest Group (SIG) has launched interoperability workshops in an effort to bridge the gap between increasing processor speeds and the less glamorous subject of server throughput.
A high-performance extension of the PCI local bus specification, PCI-X aims to deliver eight times the current I/O of standard PCI.
"PCI-X attacks the gap between ever-increasing processor speeds and server I/O," said Tom Bradicich, director of architecture and design at IBM's Netfinity server division, at the PCI-X Forum in San Jose, Calif., last week.
"The industry has matured enough to say, 'OK, the base architecture of the PC was laid out without a server in mind, and this is the weak link in the entire server area.' With PCI-X, [computer makers] are going to attack this."
PCI-X slots are backward-compatible to all 3.3-volt PCI cards, including 133MHz and 66MHz cards. Throughput delivered via this compatibility is equal to the lowest common speed of the card and PCI-X slot. Compaq and IBM plan to deliver PCI-X systems by the end of this year.
Bradicich said PCI-X, which has an I/O rate of 1GB per second, will "kick industry standard server technology up a notch" and provide immediate enterprise-level server performance until the arrival of InfiniBand, which offers a data throughput rate of 6GBps.
"It seems like the big hurdle was getting the previous I/O camps to meet together and agree on InfiniBand," explained Scott Hudson, an analyst at Cahners In-Stat Group, in Scottsdale, Ariz. "PCI-X looks like it will hold the industry over until InfiniBand, and will probably last beyond that."
InfiniBand, an I/O technology that combines all the best elements of switched fabric and system I/O, is expected in late 2001.
"PCI-X will be used for the I/O interconnects inside the actual server box," said Kenneth Jansen, director of server architecture and design at Compaq's industry standard server division. "When you go to the out-of-box experience, InfiniBand will arrive as the method of connecting the chassis."
The PCI-X SIG, in Portland, Ore., is at www.pcisig.com. IBM Corp., in Armonk, N.Y., is at www.ibm.com. Compaq Computer Corp., in Houston, is at www.compaq.com.
The PCI-X SIG's steering committee includes the following members.
* Phoenix Technologies
* Texas Instruments.