IBM will announce its latest line of midrange and high-end servers based on its Power5 technology this week. The new eServer p5 systems will be available later this year and are expected to come in two, four, eight and 16-processor boxes.

The servers are another step in IBM's effort to converge its two 64-bit server lines - the pSeries, which runs AIX and the iSeries, which runs the i5/OS operating system. The i5/OS is an updated OS/400 that was introduced with the eServer i5 systems in May. IBM began shipping eServer i5 servers last month.

"The hardware for the p5s and the i5s is virtually identical on this fifth-generation product line," said Nathan Brookwood, an analyst at Insight 64. "The i5 is typically a little more expensive because it has the i5/OS bundled into it, but if you strip out the OS, customers will see that the p5 and i5 are identically priced."

The i5 and p5 will each support AIX, i5/OS and Linux, which gives users greater flexibility. They also will share features such as micro-partitioning and IBM's virtualisation engine, which lets multiple instances of an operating system run a single box.

"Now the Unix or OS/400 choice is just a choice of software, not of hardware," says James Governor, principal analyst at RedMonk. "These systems can run each other's applications and operating environments. This is huge flexibility and will be a major win for any shop running both platforms."

Like the i5 servers, the new eServer p5 will rely on modular components, sources say. For example, the four-processor modules can be tied together to build much larger machines, giving customers the ability to increase the number of processors and the resulting processing power of the systems.

The Power5, like the Power4, is a dual-core chip, meaning that there are two processors on one core. But on the Power 5, each processor can run two application threads simultaneously, reducing idle time and making the server more efficient.

Brian Perlstein, senior technical consultant in the Design and Infrastructure group at Oakwood Healthcare Inc. in Dearborn, Mich., says he's eagerly awaiting the p5 systems because of the increased power, flexibility and partitioning capabilities.

"It's going to make workload management more usable," he says. "That's the next step in server consolidation. It's similar to what you did with storage consolidation when you started using a storage-area network. You didn't buy 30 percent or 40 percent of overhead upfront. You allocated pretty much what you needed and then as growth happened you added it. When you need more disk, you allocate it. Now, when you really need more CPU you allocate it. You don't just have it sitting there idle because then you're paying for idle CPU."

The new IBM p5 systems will compete with products from Sun and HP, such as the Sun Fire V series and HP Integrity rx7620-16, which HP is migrating to the Intel Itanium platform. HP says that its Itanium road map is much more defined, in that it supports not only several versions of Unix but also Windows and Linux.

IBM also is expected to announce later this year an IBM TotalStorage Enterprise Storage Server (codenamed Shark) based on the Power5 processor.