Glossary

IBM Power5 Glossary

IBM Power5, IBM i, and Power hardware history and migration terminology, defined in plain English.

C

• Capacity on Demand (CoD) ... IBM's licensing model that lets a Power server ship with more processor or memory capacity installed than activated, with additional capacity unlocked temporarily or permanently as needed.
• CPW ... IBM's relative performance benchmark for IBM i systems, used to compare processing capacity across different Power hardware generations and models.

E

• End of Service (EOS / EOSL) ... The date IBM stops offering standard hardware maintenance for a given system, after which factory parts, contracted field service, and firmware updates are no longer available through IBM directly.
• eServer i5 ... IBM's POWER5-based product line for IBM i (then i5/OS) workloads, the direct descendant of the AS/400, later renamed System i.
• eServer p5 ... IBM's POWER5-based product line for AIX and Linux workloads, sharing processor silicon with the eServer i5 but sold as a separate brand, later renamed System p.

I

• i5/OS ... The name used for the AS/400 lineage's operating system from 2004 to 2008, between OS/400 and IBM i, tied to the POWER5 processor generation it launched alongside.
• IBM i ... The current name of the operating system that ran the AS/400 as OS/400 and later i5/OS. Renamed to IBM i in April 2008, alongside the Power Systems brand unification.

L

• LPAR ... A logical partition: an independent, virtualized instance of an operating system running on a shared physical Power server.

M

• Micro-Partitioning ... A POWER5-era virtualization capability allowing a single physical processor core to be divided into multiple logical partitions at sub-whole-processor granularity.

P

• POWER4 ... IBM's processor generation that preceded POWER5, the last generation before Micro-Partitioning and simultaneous multithreading were introduced to the Power line.
• POWER5 ... IBM's processor generation released in 2004, the successor to POWER4, notable for introducing Micro-Partitioning and simultaneous multithreading to the Power line.

S

• Simultaneous Multithreading (SMT) ... A processor design technique allowing a single physical core to execute instructions from more than one thread at once, introduced to the Power line with POWER5.
• System i ... IBM's rebranded name, from 2006, for the eServer i5 product line, before the 2008 unification into Power Systems.

T

• Third-Party Maintenance (TPM) ... Hardware maintenance and support provided by a company other than IBM, typically used for hardware past IBM's own end-of-service date.