The DSD line requires OS/400 V4R4, and supports only Domino R5.01 and above. A license for Domino is not included with DSD boxes. IBM's position on the license is that some customers will want to move an existing Domino license to the DSD box.

If you are interested in doing applications that require data integration or Domino must co-exist with an existing AS/400-based business application, you should be examining the red-stripe "regular" AS/400e line.

If you are interested in doing only Domino mail, calendar/schedule work, and applications, you should examine the new DSD line.

It's imperative that you correctly size the AS/400 to be sure it will fit your existing environment. IBM's AS/400 for Domino Web site includes sizing information and assistance. This information can be found at: http://www.as400.ibm.com/domino/D4szintro.htm.

Enough of the history and product offerings, let's get back to where we started, primarily, "Why would you consider the AS/400 as your Domino platform?"

Why the AS/400?
IBM's AS/400 platform has been around for over ten years, a relatively long time for any product line in the computer industry. The IBM AS/400 evolved from the IBM System 36 and System 38, minicomputers designed to support business applications running on green screens. The AS/400's longevity can be attributed to its unique architecture in which the operating system, OS/400, is separated from the machine's hardware by a layer of microcode. This separation allows the operating system and applications to remain hardware independent, meaning that major upgrades to hardware only require replacement of the microcode.

Simply put, this means that the transition to a 64-bit environment was relatively simple for AS/400 customers and application vendors. Current versions of AS/400 systems are completely 64-bit capable -- this includes applications running natively in the AS/400 environment. Compare this to what it will take to move existing NT or Unix applications to a 64-bit environment (once available). At the most, 32-bit Wintel applications will require rewrites, and at the least, compilation and debugging of new 64-bit versions.

Reliability
The AS/400's biggest advantage is its reliability and availability. Simply put, AS/400s do not crash (a hard concept for technical people working in NT environments to believe). Much of this reliability can be attributed to the high level of integration between the operating system, hardware, and application layers on the AS/400.

Independent study has shown that the AS/400 has a downtime of less that three tenths of one percent per year, which translates into approximately six hours of downtime per year. This is an extremely important quality for sites requiring operation for 24 hours a day, seven days a week.

Protection and partitioning
I'm going to leave a full explanation of these two assets(i.e., protection and partitioning) for a future article. However, to understand what they provide, consider having the ability to separate your mail server from your application server within the same machine. At the same time, you have the ability to separate memory pools and priorities, meaning that you can protect a single Domino server environment from consuming all available resources. This provides separation of mail, application, and Web environments.