In Hot Pursuit of Hardware

On special assignment in Rochester, a look at the new AS/400 servers

There’s a lot of new hardware being introduced this year and we’d need a full day and a small book just to begin to get into all of it. But unfortunately, we only have a few minutes of your time and a few pages in which to work, so here it is in a nutshell.We’d also like to mention that as of this writing, there are still changes taking place in the final announcements, so we apologize in advance for any quantitative errors. And we strongly recommend that you consult the System Handbook, System Builder, or call your IBM Sales Specialist for the current limits.

Passing the Northstar

Each year, without fail, the speed at which computers process data, access data and communicate with each other increases. There seems to be no end to this trend. Not surprisingly, IBM’s AS/400 is once again raising the bar for business computer processor performance, storage capacity, speed and communications. This year IBM is introducing two new processors to the AS/400 line, the PULSAR, and the I-STAR.

New to some of the Model 270s, and all larger servers, is support for Hot-Pluggable PCI. This allows for the installation and removal of PCI devices (cards and disks) while the system is still running.
The PULSAR drives the new entry-level AS/400 servers, replacing the Northstar processor. PULSAR processors use on-chip copper wiring technology and integration provided from IBM's CMOS7s technology. Copper's better conductivityas compared to Northstar’s aluminum technologypermits thinner wires to be used, enabling the transistors to be packed closer together. The denser configuration allows for additional micro architecture methods and more on-chip cache, which improve performance.

The I-STAR processor that powers enterprise-level AS/400 servers introduces, in addition to on-chip copper wiring, Silicon on Insulator technology (SOI). With SOI, the transistors are built within and on top of a thin layer of silicon that sits on top of an insulating layer. The insulating layer is fabricated by implanting a thin slice of oxide beneath the primary silicon surface of the wafer. The resulting processor consumes less energy and increases performance from 20 percent to 30 percent.

In the AS/400 world we measure power in Commercial Processing Workload (CPW) and not MHz because we know that, just as in automobiles, there is more to performance than the top speed of your engine. This year, with e-business becoming more popular, it’s necessary to point out that the AS/400 MHz rating has doubled, which means cycle intensive activities such as some Java applications and Domino just got an additional performance boost. We’re expecting a similar increase again in another one to two years.

Riding the Bus Just Got Faster

This year the AS/400 has finally completed its transition to PCI. Many think this is a step back from the robust but proprietary SPD technology that the AS/400 world has come to believe in and rely on for its business needs. However, after a slightly bumpy start we believe the AS/400’s PCI technology will prove itself the better of the two. With the complete integration of PCI you’ll notice performance increases in the I/O processor and adapter cards, and hopefully in the coming years we’ll also see the lower cost of production for PCI reflected more in the cost of purchase.

The AS/400 bus architecture was updated with an extremely high-speed data crossbar switch complex that reaches speeds up to 36GB per second with up to 14independent buses that can each be dedicated to either memory, processors, or I/O from the PCI bus.
IBM found that, in order to complete what it calls “balanced system concept,” a new and faster data transportation mechanism was necessary in order to keep the processors busy. So the AS/400 bus architecture was updated the with an extremely high-speed data crossbar switch complex that reaches speeds up to 36GB per second with up to 14 independent buses that can each be dedicated to either memory, processors, or I/O from the PCI bus. The result is higher throughput and less competition for bus resources.

Putting the techno soup aside, what the customer will see is a high-end performance increase of 3.6 times over last year’s high-end models, as well as an increase in the maximum main storage (memory) available of up to 96GB, and increased DASD maximum, up to 18.5TB. Enhancements to disk I/O and tape backup are also expected, but final details were not available at the time we wrote this article.

More Bang For Your Buck

Two entry-level, three enterprise-level, and four custom servers make up this year’s new AS/400 models. The entry-level servers are the Model 250basically a repackaged Model 170and the Model 270.

The Model 250 is aimed at replacing the Model 150 with two processor points and a top performance rating of 75 CPW for batch and 20 CPW for interactive workload. It has a maximum of 1GB main storage and up to 10 DASD units, six of which would be located in the #7102 expansion unit. There are six PCI card slots, with an additional nine available in the #7102 expansion unit, and up to two Integrated Netfinity Servers can be supported.

The Model 250 includes a special preloaded software package made up of OS/400, Client Access, Query and DB2 Query Manager, and SQL Development Kit. All in all this is a small introductory AS/400 based on last year’s technology with little room for growth. While it has its place in the market, we wouldn’t recommend it for any core business applications where expected growth is more that 50 percent. It’s also important to note that the Model 250 will not have an upgrade path outside of the box, and most of its feature cards will not migrate to the Model 270 and 8xx servers.

The new Model 270 has been introduced to fill the rather large boots of last year's popular Model 170 Server. As the new entry-level e-business solution for small businesses, the Model 270 offers much more room for growth than its predecessor. It has performance points that range from 150 CPW to 2000 CPW (a two-way processor) with interactive ratings from zero to 70 CPW.

There is room for seven PCI cards in the system unit and another seven in the expansion unit, three of which may be Integrated Netfinity Servers. It has a maximum of 8GB main storage and 421GB of DASD (24 disk units). In order to reach maximum capacity, however, the Model 270 Server requires the system unit expansion with 12 additional disks, and an expansion tower with six additional disks.

New to some of the Model 270s, and all larger servers, is support for Hot-Pluggable PCI. This allows for the installation and removal of PCI devices (cards and disks) while the system is still running. Optional concurrent maintenance for disks can be purchased for the Model 270s that do not support Hot-Pluggable PCI. The Model 270 does not include an internal battery and does not support CPM so a UPS solution is highly recommended.

Reinforcing IBM’s vision of the Model 270 Server as the ideal e-business solution, it has a minimum interactive feature with CPW of zero, which allows for system administration by a single interactive job, Operations Navigator, and any job submitted to batch without penalty. If you try a second interactive job, however, you might consider going for coffee on the moon while you wait for your response. This limitation does not hinder e-business workloads, which don’t normally require 5250 interactive workloads. Workloads such as Domino, server-side Java, e-commerce tools, and a multitude of other e-business offerings generally see a higher ratio of CPU to I/O utilization, but with no need for 5250 interactive applications, will not be affected by an interactive CPW rating of zero. End result: more bang for your buck if you’re only interested in e-business.

Mini Mainframes and Domino Dominance

Three new enterprise-level serversModels 820, 830 and 840boast performance increases of 45 percent to 800 percent over the Model 7xx Servers and all sport Hot-Plugable PCI.The Model 820 has four main processor choices: two 1-way processors, a 2-way, and a 4-way. These four processor points give the Model 820 performance ratings from 370 CPW up to 3,200 CPW with a 16GB maximum for main storage. A maximum interactive performance value of 2,000 CPW can be purchased if the base 35 CPW is not enough. It will support over 4TB of DASD and 12 Integrated Netfinity Servers.

The Model 830 comes in three flavors: 2-way, 4-way, and 8-way. Performance ranges from 1,850 CPW to 7,350 CPW and interactive maximum of 4,550 CPW. It can contain a maximum of 32GB of main storage and 10.8TB of DASD with 16 Integrated Netfinity Servers. It comes with RAID5 protection standard in the system unit if you order at least four disk units, two hot swap power supplies and an internal battery for redundancy.

The new Model 840code named Goliathis big and powerful with the entry processor coming in at twice the CPW rating of the biggest Model 740. There is a 12-way processor with 10,000 CPW, a 24-way with 16,500 CPW, and many interactive features to choose from which will give you as much processing power as you can handle. With an upper interactive feature of 16,500 CPW, matching the non-interactive workload, we had to double check to see if it would be a repeat of last years 4,550 CPW feature. The technicians at the lab hold firm that it has been tested at the full 16,500 CPW and we think they mean it.

In addition to the standard server models there are six new Dedicated Server for Domino (DSD) machines. These new DSD machines use the Model 270 box and Model 820 box, with a Simple Mail Users (SMU) top-end support of 14,400 users and Mail and Calendaring Users (MCU) top-end support of 8,910. There are two Custom Servers: an SB2 with an 8-way processor and an SB3 with a 12- or 24-way processor choice. The SB2 Server is basically a top end Model 830 server with support for only four DASD units. The SB3 is one of the two Model 840 servers with support for only six or eight DASD units.

Tying it all Together

Having briefly described the new processor and bus technology and AS/400 server choices for this year we’d like to take a few sentences to introduce HSLHigh-Speed Linkand discuss the withdrawal of CPM.

High-Speed Link is the new cabling mechanism that will replace Opti-Connect for attaching towers to the System Units. HSL is made up of pairs of ports and each tower is attached to a single port, then looped back to that port's pair. If a break occurs anywhere in the loop, the system unit will talk to the tower on the other HSL port, thus providing redundancy. HSL can transmit data in both directions at 500MHz with an effective data rate of approximately 350MB/second for an overall throughput of 750MB/second.

Because this is new technology it’s wise to expect some exceptions on the performance and redundancy in migration environments with a mix of old and new models.The Model 270 supports one loop and one tower on that loop. The Model 820 also supports one loop but a total of five towers on the loop. The Model 830 supports four loops with a total of 13 towers and the Model 840 supports eight loops with 24 towers. There are performance limitations that need to be considered when arranging towers on the HSL loops, obviously the more towers per loop, the less performance.

Continuously Powered Main store (CPM) support will no longer be available. When we first heard this we were in shock. How could IBM drop such a key part of the AS/400’s availability technology?

In answer, here are the main factors in this decision. First, due to the increase in main storage capacity the batteries required to keep CPM running were becoming extremely heavy and expensive. Couple this with the fact that most users with availability issues have good UPS solutions and shouldn’t need it, and you see a little light at the end of the tunnel. As well, IBM is confident that other enhancements such as System Managed Access Path Protection (SMAPP), new highly reliable directories, and faster IPLs will reduce system down time should it ever occur. What about that data in main storage that didn’t have time to be written to disk when the UPS solution failed? Gone! So sorry, hope you had journaling. Anyway, this is a long discussion and we only had a couple of hours at IBM Rochester to hear and discuss the reasoning behind this withdrawal, so we will have to leave you with our opinion.

While we can see and agree with the reasoning on its requirement being much lower and the impacts being minimal, we still think it would be nice for the customer to have the choice. In IBM’s defense however, how many other vendors include CPM?

IBM's new AS/400 announcement is about hardware. The hardware boasts breathtaking technologyindustry’s leading edge shared across IBM systems and, in the case of the AS/400, optimized for mixed transaction servers. It’s tuned for a mixed bag of e-business functionality coupled with the rock solid reliability required for a back-office transaction engine. In the case of this announcement, IBM has gone out of its way to not abruptly change or force updating of models, but rather to emphasize an AS/400 family.

Not surprising is that in the foreseeable future, the customer will pay for performance and not for whatever the underlying technology is. The more performance you need, the better the technology gets, and the more you’ll pay. You pay for what you need, and what you need is what you get.

Related Editorial:

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