ClearPath Next-Generation Server Architecture Debuts on OS 2200

The ClearPath Dorado Model 400 Servers are the first members of the Dorado family of servers based on the ClearPath Next-Generation Server Architecture. They currently include two entry-level models:

Dorado Model 400 servers debut support for the OS 2200 operating system running on Intel® Xeon® Dual-Core processors. The systems were announced in the spring of 2007 and have been shipping since mid-2007.

Many OS 2200 clients have expressed interest in the entry-level Dorado Model 420 and 430 systems to replace older OS 2200 platforms, as well as to support development and test activities. But let's be honest — there's a healthy bit of skepticism among OS 2200 aficionados when it comes to running their applications and OS 2200 executables on an Intel® processor, particularly without recompiling. Compatibility is very important to ClearPath customers — and always has been.

Unisys understands these concerns, and our engineering teams have done a tremendous amount of work to make the transition to Intel® processors a transparent one. Let's take a look at the testing that's been done behind the scenes to enable a smooth transition to ClearPath Next-Generation Architecture for the OS 2200 operating environment.

Testing, Testing, One — Two — Three
Our compatibility goal with Dorado 400 servers is the same as with any new ClearPath server model — provide a seamless migration path such that all existing programs run on the new platform without recompiling or re-linking. And, we have achieved that goal.

First, we rigorously tested the Dorado 400 systems with the complete central complex and I/O test suite that was used with previous Dorado 300 systems. What's more, we developed additional tests that focused on:

  • The new infrastructure layer that Unisys developed to adapt the OS 2200 operating system to the Intel® processor-based platform
  • The management interfaces to that infrastructure layer
  • Error recovery in the infrastructure layer software

For example, we wanted to confirm that real-time runs on a software-implemented Instruction Processor (IP) would receive their true share and priority from the Intel® processors. So, tests were created and executed to verify that the software-implemented OS2200 IPs had the same behavior as our custom Dorado IPs. The results showed that the behavior was the same. Other tests were developed to look for any communications degradation or performance quirks when running through the Intel® network I/O infrastructure — and it was found that performance met or exceeded that of previous Dorado systems.

We also ran product function tests for the compilers, BIS, EAE, and databases. For example, BIS function testing included accessing RDMS, as well as remote databases (Oracle, Microsoft SQL Server, etc.) via MRI. And, we resurrected several 30-year-old absolutes from very old products, such as Fieldata FORTRAN, and found that all of these ran without a hitch on the Dorado 400.

Finally, an existing compatible disk subsystem, complete with programs and data, was cross-connected to the Dorado 400 and successfully run.

In all these cases, the ClearPath Dorado Model 400 Servers came through with flying colors!

Testing: Parts 2 and 3
We also invited several of our partners to test their software on the Dorado 400 server platforms. So AIS (Applied Information Sciences), Sightline, SMA (Software & Management Associates), and TeamQuest did just that — and, again, the results were perfect. We provided access to Dorado 400 servers inside the Unisys firewall, so partners could load software and run tests — all from the comfort of their own offices. The feedback and results from this innovative approach were so positive that we plan to do more of it in the future.

Finally, we tested a large, complex COBOL application provided by one of our customers. The program performs sophisticated insurance rate calculations, including some heavy-duty math. The insurer sent Unisys its applications and databases and our Roseville QA team took it from there. The tests ran for several hours and the output was compared to that of the insurer's "home" Dorado server. The results matched up to a "T" on the very first try. Needless to say, the customer was delighted.

Monster Mix
Of course the real test of a ClearPath server is showing that the system can sustain a stressful, intensive workload. So, we developed the concept of a "Monster Mix," which includes high-volume, simultaneous batch and online workloads that are repeatedly and extensively run on the Dorado 400 Server. The following is one example of the workload, duration, and performance (run for 12 hours on a 420 MIPS (6 IP) system):

  • 150 Batch runs, 514 Demand runs, 4,000 TIP terminals, 120 transactions per second, and 21 percent real-time concurrent workload
  • Peaked at over 3,000 I/Os per second and 22,000 Interrupts per second — and kept all 2200 processors 100 percent busy for 10 hours during the 12 hour run.

This convinced us that we could handle the kind of workload expected by the customers who purchase a Dorado 400 Server. It also confirmed that the platform delivers the level of reliability expected for OS 2200.

Changes Were Needed
In the interest of full disclosure, 12 of the nearly 200 OS 2200 system software products required changes. Now, if you're thinking "12 is 12 too many!" please allow us provide a bit of context.

First, there are six products that we have to change for every new Dorado platform, not just the 400 — because they gather, graph, and report performance metrics. And second, there are certain products that must read the system log. There were new entries in this log for the Dorado 400, so those programs had to be updated and recompiled.

Where Do Things Stand Today?
EMC Corporation has been running a Dorado 400 server since the first of May and has not experienced any Dorado 400-unique stops. In addition, Unisys is using a Dorado 400 system to support a number of its programmer teams with outstanding stability in this complex and variable environment.

More importantly, we have completed the installation of two Dorado 400 servers for a customer in Europe and one for a customer in the United States. The installations have gone very smoothly and both are planning their production cutover in early 2008.

The Bottom Line
ClearPath Dorado Model 400 Servers are ready for primetime!

If your organization has a goal to only purchase commodity (Intel® processor-based) hardware, then the Dorado 400 Server with ClearPath Next-Generation Server Architecture and Intel® technology satisfies that objective. Plus, it provides a well-priced option to replace older ClearPath platforms, particularly for smaller OS 2200 shops. Finally, it's a great choice as a development and/or test platform for larger organizations that are looking to get some experience with Next-Gen.

For more information about Dorado Model 400 servers, visit the eCommunity at