6. PCIX
Managers of enterprise networks should get help increasing bandwidth and minimising performance bottlenecks in 2001 from the new PCIX bus architecture, which has the potential to dramatically increase I/O performance in enterprise servers.
Since its development in the early '90s, the PCI local bus has been a fundamental component in most computer systems. It replaced the legacy ISA bus as the de facto peripheral bus in all systems, from home computers to enterprise servers.
Most PCI buses now in use are 32-bit and limited to speeds of 33MHz and 133M-bps throughput. Faster enterprise servers are built with the 66MHz PCI buses with 64 bits of bandwidth, but even those servers can't keep pace with the components around them. The latest processors handle transmissions considerably faster than a 66MHz PCI bus can, as do peripheral devices based on Fibre Channel, Gigabit Ethernet or Ultra160 SCSI.
The proliferation of distributed computing is also driving demand for a faster bus architecture. As enterprise sites add clustered server farms and shared storage with switched-fabric storage area networks to meet demand for greater scalability and higher availability, bus speed becomes critically important.
To break the current PCI speed barrier, Compaq, Hewlett-Packard and IBM joined forces in 1998 to develop the 64-bit PCIX bus architecture, which will run at 133MHz and attain throughput of 1,066M bps.
An important aspect of the new PCIX bus architecture is backward compatibility with the current PCI standard. A PCI adapter will function in a PCIX system and vice versa, but a PCIX adapter used in a PCI bus will be limited to standard PCI speeds.
The PCI Special Interest Group approved the PCIX standard in September 1999, and vendors are expected to ship the first PCIX-enabled product at the end of this year or early next year.
Although it will improve throughput significantly, the PCIX architecture will eventually be replaced by the InfiniBand interconnect architecture that is now in development. With InfiniBand-based products still two to three years away, the HAL 9000 supercomputer will likely miss its 2001 ship date, but the PCIX bus will become part of the IT landscape.
