By Dan Jones
Advanced Micro Devices Inc’s ambitions for its Athlon processor in the enterprise server market have been given a shot in the arm by Hotrail Inc, which has announced that it is developing four and eight way symmetrical multiprocessing (SMP) chipsets for the CPU. The San Jose, California-based firm, formerly known as Poseidon Technology, is claiming a technology lead over Intel’s Corp’s Corollary Profusion chipset, with its simultaneous switched matrix design. President and CEO, Rick Shriner, says that Hotrail design can handle four memory transactions when the Intel system is dealing with one.
The problem with the Corollary design, Shriner explained, is that it uses a shared bus set-up that marries two Intel four ways in the Corollary eight way ‘crossbar’. This means that instructions are handled one line at a time but stacked eight deep, leading to bottlenecks, Shriner claimed. He said using the crossbar design; the Intel chipset could support a bandwidth of up to 1.6Gb per second per processor. The multiple pipes of the Hotrail would support 3.2Gbps, he claimed, or a total bandwidth of 12.8Gbps in a four way design.
The key to the Hotrail SMP design is the Flow Control Unit (FCU), a central staging area which ensures that the CPUs can work simultaneously. In other SMP chipsets, each time an action is required, all the processors are snooped to determine which has the capacity to deal with the task. In the Hotrail design, the FCU holds the records of what each processor is doing, saving time over systems that first have to check the processor’s status. The FCU can decide ‘on the fly’ which path is most efficient for carrying data or instruction between the CPU and, for example, a location in the main memory. So, in the Hotrail design, the FCU, not the central bus, becomes the main focus of system activity and the FCU is connected to each CPU, I/O bridge and memory interface. This means that it need not solely be used for servers.
Shriner said he felt the technology could also come into play in internet data processing and telecommunications applications. He envisaged it being used in edge routers – a convergence between servers and routers – a technology he said was being driven by the internet, which required intensive computing power plus the routing of network packets. He said that the design’s ability to select high bandwidth and low processing power or vice versa would also make it suitable for telecommunications applications.
However, the Hotrail SMP design will be initially targeted at the server market. Shriner was keen to stress that the design is processor agnostic although he claimed to be in lockstep with AMD at the moment. He expects that Hotrail could ride on AMD’s coat tails and gather around 10% of the SMP market. For a small start-up like ourselves that would be very, very good business, he commented. And despite Intel’s problems in delivering the Corollary chipset to market – Intel now says that product will be available in late summer – Shriner thinks that Intel will welcome Hotrail to the party. They’re not going to be negative on someone else developing the marketplace, he said. And he didn’t rule out developing chipsets for Intel in the future. Alpha-based systems may also be a possibility as the system has been developed to make the transition to Alpha processors as easy as possible according to Shriner.
The company will start to validate the chipsets early in 2000. Shriner did not want to give a definite answer on when the chipsets would be generally available, saying: this is really difficult stuff to do …the likelihood is that there’ll be product in mid 2000. Hotrail, a fabless company, is looking to IBM Corp’s Burlington plant as its primary foundry but also has a deal with Taiwan Semiconductor Manufacturing Company. The first chipsets will built on a 0.25 micron process but will go to 0.18 micron after around a year’s production. Shriner says that the four way chipsets will be the first produced but that once the four way is operable the eight way is easy.
The company has so far scored $16.1m in funding to support the expensive process of semiconductor-related development. The company, which started in 1993, has ex-employees from Apple Computer Corp, Digital Equipment Corp and Sun Microsystems among its number. Shriner says that 80% of the company’s employees are involved in the firm’s SMP development work.
