Jumping on the PCI Bus: Part 2 of a 2-Part Series

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As we learned in last week's article, IBM's shipment of POWER4 iSeries servers and OS/400 V5R2 will have big implications for owners of System Product Division (SPD) expansion units and I/O cards. However, upgrading your current systems to POWER4 servers will have different implications for your I/O infrastructure than upgrading them to OS/400 V5R2.

To understand the migration issues you'll be facing, let's sort out the options you'll have once IBM ships OS/400 V5R2 and POWER4 servers. (This event will likely occur between the middle and the end of the third quarter.) Here are three choices you could make for the servers at your site:
  • Replace them with a POWER4 server or a newer, non-POWER4 server
  • Upgrade them to a POWER4 server or a newer, non-POWER4 server
  • Upgrade your servers to OS/400 V5R2, but don't upgrade the hardware


Let's examine these choices in order so we can better understand their consequences.

Replacing and Consolidating Servers

Today, thousands of AS/400 customers own older systems that they cannot upgrade. For instance, owners of 4xx/5xx and 6xx/Sxx series cannot upgrade their systems because IBM no longer offers upgrades for them. Model 150 and 170 owners face the same situation because these servers have never been upgradeable.

If you own any of these models and need more capacity, you can always buy additional servers off the used equipment market. Before you do that, however, consider replacing all of your older systems with a single server. While the initial cost of this alternative will be higher, chances are good that your total cost of ownership over time will be significantly lower. In particular, you could realize significant savings on hardware maintenance, power, and cooling expenses.

The issue, of course, is determining which server you should consolidate to. If you consolidate onto a POWER4 server, you won't be able to migrate over any of the following devices and peripherals that you may currently own:

  • Disk drives that rotate at less than 10,000 RPM or that have less than 8 GB capacity
  • Any SPD expansion towers (Note: The 5065 and 5066 expansion towers will not directly migrate, but they can be converted to 5074 and 5079 towers that will be POWER4-compatible)
  • Any migration towers, such as the 5033 or 5077
  • Any SPD I/O adapters (IOAs) or I/O processors (IOPs)


Upgrading to POWER4, therefore, will involve replacing these devices with newer ones. You'll also have to rekit any 10,000 RPM disk drives running in SPD expansion towers (at $150 apiece) and replace some older PCI IOAs and IOPs that are not PCI-node compatible. These replacements will cost anywhere from $425 to $1,925 each.

Of course, many customers have none of the above devices or just a handful of them. If you're such a customer, replacing your older servers with a POWER4 system may be the best option. However, if you have many of these devices, your replacement costs could put you over budget. In such cases, your best bet may be to consolidate your older servers onto an AS/400 7xx or iSeries 8xx. These servers will support your old SPD devices either directly or, in the case of the iSeries 8xx, via a migration tower. They will also support OS/400 V5R2 and allow you to run V5R1 and V4R5 systems in secondary LPARs. Note, however, that the 7xx series only supports full-CPU LPARs rather than the fractional LPAR capabilities of the 8xx.

Consolidating onto an iSeries 8xx may be your best option if you have short- or intermediate-term plans to upgrade to POWER4 (say, within two years). Since the 8xx supports SPD (via migration towers) as well as PCI, it allows you to convert your SPD devices and expansion towers to PCI-node components running over High Speed Link (HSL) interconnects, and do so over a period of months or years. In this way, you can create an I/O infrastructure around the 8xx that is fully compatible with POWER4 server requirements, but "amortize" the cost and effort over time. Then, once you're ready to upgrade to POWER4, all you have to do is upgrade the system unit.

Upgrading Rather than Replacing: Considerations for Model 7xx Owners

Unlike owners of the older systems discussed above, those of you who are 7xx owners can still upgrade to a newer system and avoid the tedious task of unloading and reloading data. Like the owners of older models, however, you face the dilemma of whether or not to upgrade to POWER4.

If you're in this position, do what I described above: inventory the outmoded disk drives and SPD devices you own and determine the cost and effort involved in converting them to PCI and HSL. If the cost busts your budget, consider upgrading to an 8xx and "amortizing" your SPD to PCI conversion over time.

By the way, those of you who know accounting rules may be wondering about the balance sheet implications of an upgrade from a 7xx or 8xx system to a POWER4 server. As you might know, IBM's RS/6000 and pSeries customers cannot keep the serial numbers of their existing systems if they upgrade them to POWER4-based "Regatta" Model p690s. Losing a serial number can force a company to account for an upgrade as if it had disposed of the upgraded system, an event that can cause a substantial balance sheet loss. By contrast, I don't expect this to happen to 7xx and 8xx owners who upgrade to POWER4. As the old saying goes, "Don't ask me how I know this or I'll have to kill you." Let's just say that IBM has a history of preserving AS/400 serial numbers, and I'm relatively certain that the company will do so once again.

Upgrading to OS/400 V5R2 on Existing Systems

If you don't need additional processor capacity but want the added functionality of OS/400 V5R2, you'll be able to upgrade to the new release on any Model 150, 170, 250, 270 6xx, Sxx, 7xx, or 8xx. As we discussed last week, this option will not force you to convert your SPD devices to PCI. Realize, however, that you will only be able to do a single-step upgrade to OS/400 V5R2 from V4R5 or V5R1. As such, it is important for you to be on one of these releases to avoid multiple-step upgrades or a complete OS/400 reload.

Just as importantly, you need to be on one of these two releases by July 2, 2002. That's the final date when you can order single-step upgrades to V4R5 from V3R2, V4R1, V4R2, V4R3, or V4R4. If you're on V4R4, however, you'll also be able to upgrade directly to V5R1 after July 2, 2002. IBM has yet to set a date when this upgrade option will expire.

Final Thoughts

Of course, there is a fourth option you can take in response to IBM's upcoming announcements: Do nothing. By now, however, I hope you can see that doing nothing could hurt you. If you plan on increasing your servers' capacity in the future, chances are good that consolidating on a newer server and migrating to PCI (even if it takes a couple of years) could save you money in the long run. And if you don't act by early July to bring older OS/400 releases up to date, you could add needless complexity to future upgrades. Keep these possibilities in mind as you plan your upgrade strategies over the coming months.

Lee Kroon is a Senior Industry Analyst for Andrews Consulting Group, a firm that helps mid-sized companies manage business transformation through technology. You can reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..

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