The IBM System p is a high-end line of RISC (Power)/UNIX-based servers. It was the successor of the RS/6000 line, and predecessor of the IBM Power Systems server series. History The previous RS/6000 line was originally a line of workstations and servers. The first System p server line was named the eServer pSeries in 2000 as part of the e-Server branding initiative. In 2004, with the advent of the POWER5 processor, the server family was rebranded the e''Server 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 again renamed to System p5. The System p5 now encompassed the IBM OpenPower product line. In 2007, after the introduction of the POWER6 processor models, the last rename under the System p brand dropped the p (numbered) designation. In April 2008, IBM announced a rebranding of the System p and its unification with the mid-range System i platform. The resulting product line was called IBM Power Systems. Hardware and software Processors Whereas the previous RS/6000 line 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, during the SuperComputing 2007 (SC07) conference in Reno, IBM introduced 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. Features All IBM System p5 and IBM e''Server p5 machines support DLPAR (Dynamic Logical Partitioning) with Virtual I/O and Micro-partitioning. System p generally uses the AIX operating system and, more recently, 64-bit versions of the Linux operating system. Models BladeCenter IBM BladeCenter JS12 (POWER6) IBM BladeCenter JS22 (POWER6) IBM BladeCenter JS23 (POWER6) IBM BladeCenter JS43 (POWER6) Main line eServer pSeries IBM eServer pSeries 610 (7028-6C1 & 6E1) IBM eServer pSeries 615 (7029-6C3, 7029-6E3) (1~2-core POWER4+ CPU) IBM eServer pSeries