IBM aims to boost Unix server line against Sun

IBM's acquisition of Sequent Computer Systems will bear fruit a year from now with the arrival of a new Unix server code-named Regatta that will incorporate as many as 32 CPUs.

The new server will bolster IBM's effort to grab business from Sun Microsystems. Though IBM's Unix server business has been growing--it expanded 30 percent last quarter--Sun's is bigger. Hewlett-Packard, Compaq Computer, SGI and Unisys, too, are striving to capture more of the market to fill the server appetites of big businesses and Internet companies.

The new design, a highly complex confluence of several hardware and software developments, illustrates both the difficulty of designing high-end systems and the lengths to which computing companies are going to satisfy demand for them.

Regatta will combine several new technology advances, said David Turek, vice president of deep computing and Web servers at IBM. First will be the Power4 chip, which, as reported, joins two CPUs in a single processor package.

Sets of four Power4 chips will be nestled together in eight-CPU packages, Turek said. As many as four of the modules can be joined together in Regatta.

Second will be a high-speed switch used to connect these eight-CPU modules, Turek said. The switch comes from IBM's current RS/6000 SP Unix server design. IBM's newly released SP uses the same "Colony" switch that appears in IBM's ASCI White supercomputer at Lawrence Livermore National Laboratory, but Regatta will use a next-generation switch code-named Federation.

Third will be nonuniform memory architecture (NUMA) technology from Sequent. NUMA is a computer design that spreads memory around in separate chunks near different CPUs. NUMA contrasts with symmetrical multiprocessing (SMP), which uses a single "flat" chunk of memory shared by all the processors.

SMP designs are used in high-end Unix servers from IBM, Sun, Compaq and HP. But designs from SGI, Sequent and EMC's Data General division use NUMA. SMP has survived much longer than many expected it would, but it's still limited by the bottleneck of having numerous CPUs sharing the connection to memory.

One difficulty with NUMA is dealing with memory that is located at different spots around the system, which results in different delays when a CPU is trying to read or write from memory. IBM's new switch means these delays, called latencies, will be measured in mere billionths of a second, as opposed to the millionths of current systems, IBM said.

"We'll be trying to make the NUMAness as invisible as possible," Turek said.

Regatta will use chips with IBM's copper and silicon-on-insulator technology. They'll run faster than 1 GHz and will each have a whopping 170 million transistors.

Sun's new high-end server, code-named Serengeti and due next year, also deviates from the straight SMP approach. At the other extreme, SGI's new 256-processor Origin 3000 is SGI's third-generation NUMA design.

A high-end Regatta server will debut in the fall of 2001, Turek said. A midrange version will arrive in the spring of 2002.

Setting the stage for Regatta will be a new version of IBM's Unix, called AIX. The new version, previously known as Monterey, will officially be released under the name AIX 5L, IBM said.

Monterey used AIX at its core and added contributions from versions of Unix from Sequent and Santa Cruz Operation. Though the alliance initially was portrayed as a marriage of equals, IBM was in fact in the driver's seat, as reflected by the software's ultimate name.

AIX 5L will run both on servers using IBM's Power chips and on Intel's upcoming IA-64 chip family, which launches next year with the arrival of the Itanium chip. Though higher-level software can be written identically for AIX on either chip type, it will have to be "recompiled" to run on the two different chips.

IBM--a company so large it's difficult to count how many operating systems it supports--also is an avid fan of Linux, a relatively young clone of Unix.

IBM believes Linux will become the standard foundation of most programming efforts. SAP, for example, has settled on Linux as the basic operating system for developing its high-end accounting, sales and manufacturing control software, Turek said.

Counter to this assumed ascendency of Linux is IBM's view that Linux isn't as good as AIX or other versions of Unix at high-end tasks such as staying up and running as much as possible or running efficiently on systems with dozens of CPUs.

To accommodate this contrasting popularity but high-end immaturity, IBM AIX 5L will be able to run Linux software that has been recompiled for AIX, Turek said. Doing so will mean Linux software can take advantage of AIX's multiprocessor abilities and other advantages, he said.