PSeries

The System p, formerly known as RS/6000, was IBM's RISC/UNIX-based server and workstation product line.

In April 2008, IBM announced a rebranding of the System p and its unification with the System i platform. The resulting product line is called IBM Power Systems.

RS/6000 was originally a line of workstations and servers. The server line was then renamed to the eServer pSeries in 2000 as part of its e-Server branding initiative.

In 2004, with the advent of the POWER5 processor, the family was rebranded the eServer p5. In 2005, following IBM's move to streamline its server and storage brands, worldwide, and incorporating the System brand, with the Systems Agenda, the family was renamed yet again as System p5.

The System p5 now encompasses the IBM OpenPower product line. After the introduction of POWER6 processor models, the new models were released under the System p brand, dropping the p (numbered) designation.

Whereas RS/6000 used a mix of early POWER and PowerPC processors, when pSeries came along this had evolved into RS64-III and POWER3 across the board—POWER3 for its excellent floating-point performance and RS64 for its scalability, throughput, and integer performance.

IBM developed the POWER4 processor to replace both POWER3 and the RS64 line in 2001. After that the differences between throughput and number crunching-optimized systems no longer existed. Since then System p machines evolved to use the POWER5 but also the PowerPC 970 for the low-end and blade systems.

The last System p systems used the POWER6 processor, such as the POWER6-based System p 570 and the JS22 blade. In addition IBM introduced during the SuperComputing 2007 (SC07) conference in Reno a new POWER6-based System p 575 with 32 POWER6 cores at 4.7 GHz and up to 256 GB of RAM with water cooling.

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