It’s summer in Rochester, so it must be announcement time for IBM’s AS/400 line of minicomputers. And now that the RS/6000 division has more or less been moved to Minnesota, it must be time for RS/6000 announcements as well. The latest word on the street has IBM debuting new AS/400s on or about September 1, although that date could slip as far as mid-September or be moved ahead to late August. Around the same time, IBM is set to announce a new series of RS/6000 servers that are based on AS/400 technology, much as it did late last year with the RS/6000 S70 Raven server. Both the AS/400s and the RS/6000s using Northstar are set to ship in the third quarter.
By Timothy Prickett Morgan
IBM first started talking officially about Northstar and its follow-on, Pulsar, at the end of May (CI No 3,341), but it didn’t say a whole heck of a lot. Both Northstar and Pulsar apparently use design elements from the AS/400’s Apache chip (from 1997) and Muskie chip set (from 1995). The Northstar and Pulsar chips are also being referred to as the Power3 and Power3+ on IBM’s PowerPC roadmap. Both chips will be used in IBM’s AS/400 and RS/6000 lines and are the centerpieces of its ASCI Blue and ASCI White multiple teraflops supercomputers, which will be employed by Lawrence Livermore Laboratory to perform nuclear weapons tests that skirt around the Nuclear Test Ban Treaty. IBM says that Northstar will be made using Big Blue’s 0.25 micron CMOS-6X process and that Pulsar will use the 0.2 micron CMOS-7S copper chip process that IBM announced late last year. It says that the Pulsars will crank up to 600 megahertz and contain up to 15 million transistors. It is likely that the Northstars will have clock speeds between 225 and 300 megahertz; exactly where depends on how well IBM gets the two integer execution units on the chip to work together. (Most chips have only one integer unit, but the ill-fated PowerPC 620 and the AS/400 A30 Muskie chip set had two.) Pulsar will probably ship this time next year, maybe even a little later, and is rumored that the Pulsar servers in the AS/400 and the RS/6000 lines will be able to support up to 24 engines in a single SMP server. Even though more than half the MIPS of that 24-way Pulsar server would go right up the chimney, that machine would still be able to process between 100,000 and 130,000 TPC-C TPM (the lower number is with AIX, the higher number is with OS/400 V4R4). That puts Pulsar on par with even the most optimistic estimates for Intel’s first 64-bit processor, Merced, which is due about eight months after Pulsar hits the streets. IBM hasn’t said when it will finally dump the 32-bit PowerPC 604e chips for either the Northstar or the Pulsar, but there’s little doubt in anyone’s mind that the 604e has, at least as far as the workstation and server business is concerned, gone about as far as it can go. If IBM wants to compete against the onslaught of Pentium II Xeon workstations, it has got to get 64-bit PowerPC chips in the RS/6000 line. The Raven server, which is the only 64-bit machine, is not enough. Moreover, it has got to get a fully-fledged 64-bit AIX out the door; AIX 4.3.1 has enough 64-bit functionality to be branded with the 64-bit Unix 98 specification, but it still has a 32-bit kernel (much as Sun’s Solaris still does). That means that much of AIX is running in 32-bit mode on the 64-bit PowerPC chips like Apache, Northstar and Pulsar (this backwards compatibility is provided in those chips’ hardware), and this slows it down.
Blackbird
According to IBMers familiar with the Northstar, an RS/6000 S70 Blackbird using twelve of these new PowerPC chips will be able to process over 7,000 HTTP operations per second on the SPECweb96 benchmark test. This compares quite favorably to the Blackbird’s predecessor, the twelve-way S70 Raven server, which rated only 4,075 HTTP operations per second. The Blackbird similarly bested SGI Origin 2000s, Sun Ultra Enterprise 4000s and Fujitsu 7000s on the same SPECweb96 test, but it did so mainly because it had four more engines, not because those engines were appreciably faster on web workloads. While the Northstar is a very powerful processor, where the rubber hits the road on the information highway – the web server – at least for RS/6000s, Northstar doesn’t give customers as much power as the raw specs for the chips will suggest when it is announced in September. On more traditional online processing tests like TPC-C, expect the Blackbird to have just shy of twice the performance of the Raven. That puts Blackbird at around 34,000 TPC-C TPM compared to 18,000 TPM for Raven. The Blackbird will be shipping in the third quarter, very likely simultaneously with the AS/400 650 model that will be exactly like the Blackbird except that it will use the AS/400’s faster and proprietary memory and I/O subsystems. With transaction rates between 45,000 and 50,000 TPC-C TPM, the AS/400 version of Blackbird will be big enough to handle all but the most ridiculously large ERP workloads or the most poorly written code. The former is only important for IBM’s biggest AS/400 customers, while the latter will be more important for the base as a whole as the Year 2000 approaches and all AS/400 shops scramble to make their RPG programs and DB2/400 data bases century friendly.
