IBM Power Systems

Power Systems is IBM's Power Architecture-based server line.

Before the Power Systems line was announced on April 2, 2008, IBM had two distinct Power-based lines: the System i running IBM i (formerly i5/OS and OS/400) – and the System p series running AIX or Linux.

IBM had two distinct Power Architecture based hardware lines since the early 1990s:

They merged to use essentially the same hardware platform in 2001/2002 with the introduction of the POWER4 processor. After that, there was little difference between both the "p" and the "i" hardware; the only differences were in the software and services offerings. With the introduction of the POWER5 processor in 2004, even the product numbering was synchronized. The System i5 570 was virtually identical to the System p5 570.

In April 2008, IBM officially merged the two lines of servers and workstations under the same name, Power Systems, with identical hardware and a choice of operating systems, software, and service contracts. In February 2010, IBM announced new models with the new POWER7 microprocessor.

IBM Power Systems models:

...
Wikipedia