|Source model||Closed source|
|Latest release||7.2 TR3 / November 20, 2015|
|Marketing target||Minicomputer and enterprise server|
|Kernel type||shares many Microkernel (SLIC) and Virtual machine (TIMI) design philosophies|
|Official website||IBM i|
IBM i is an EBCDIC-based operating system that runs on IBM Power Systems and on IBM PureSystems. The name was introduced in 2008, and it is the current evolution of the operating system, previously named i5/OS, and originally named OS/400 when it was introduced with the AS/400 computer system in 1988.
The early IBM System/36 and IBM System/38 series customers were a key target of the AS/400, so OS/400 (and its descendants i5/OS and IBM i), have built-in subsystems that provide backward compatibility with these earlier IBM general business systems. IBM i programs, like System/38 programs before them, contain both processor-independent "virtual" binary code and processor-dependent executable binary code. Compilers for IBM i produce the processor-independent code as their output; the operating system automatically translates the processor-independent code into the processor-dependent code as needed, without the need for source code or attention by IT personnel. Notably, when migrating from a legacy processor, the only effect that most organizations notice is that the program runs somewhat longer when it runs for the first time on the new computer. Migration consists of taking a backup from the old computer, and restoring it on the new.
IBM designed IBM i as a "turnkey" operating system, requiring little or no on-site attention from IT staff during normal operation. For example, IBM i has a built-in DB2 database which does not require separate installation. Disks are multiply redundant, and can be replaced on line without interrupting work. Hardware and software maintenance tasks are integrated. System administration has been wizard-driven for years, even before that term was defined. This automatic self-care policy goes so far as to automatically schedule all common system maintenance, detect many failures and even order spare parts and service automatically. Organizations using i sometimes have sticker shock when confronting the cost of system maintenance on other systems.
Another peculiar feature is that this system was one of the earliest to be object-based. Unlike traditional OSes like UNIX and Windows NT there are no files, only objects of different types. It implemented one of the earliest-known systems for persistent objects. Further, the objects persist in very large, flat virtual memory, called a single-level store.
The IBM i Access licensed product includes iSeries Navigator, a client-based and web-based graphical tool for administration of the system, database, Apache web server, and WebSphere Application Server. IBM Systems Director Navigator for i now can be used to manage target servers running IBM i 5.4, 6.1 or 7.1 from a single browser environment with the IBM i 7.1.
In 1999, IBM introduced logical partitioning (LPARs) with i5/OS to support multiple virtual systems on a single hardware footprint.
In 2007, IBM and MySQL AB announced a joint technology and reseller agreement to bring support for the MySQL open source database and DB2 for i as a certified MySQL storage engine to the IBM i platform, which was later in 2011 dropped by MySQL AB.
In 2013, IBM and PowerRuby Inc. announced PowerRuby as a commercially supported port of the Ruby programming language and the Ruby on Rails Web application framework for IBM i. PowerRuby will be offered as a free download to be installed on customer machines.
When IBM announced the new Power Systems line of servers on April 2, 2008, they renamed the operating system from i5/OS to IBM i and changed the version identifier format from VxRxMx (Version, Release, Modification, e.g. V6R1M0) to the more standard format (e.g. 6.1).
The latest version of IBM i is 7.2, announced on April 28, 2014 and released on May 2, 2014 (Version Support Schedule).
With 7.1, IBM started delivering new updates to the operating system via Technology Refreshes, where number 10 was released in May 2015.
Version 7.2 latest refresh TR3 was released in November 2015.
User groups have played a major part in the evolution of the IBM i. The largest such group is COMMON. The Young i Professionals (YIPS)  is another group that has been significant in influencing the direction of the IBM i.
- Soltis, Frank, "Inside the AS/400"; Frank Soltis was the AS/400 system architect.
- "Node.js". IBM i Technology Updates - Open Source Technologies.
- IBM Introduces the First in a New Generation of Power Systems
- "Planned Availability Date". IBM i 7.2 TR3 and IBM i 7.1 TR11 offer performance, usability, and integration enhancements.
- "COMMON". COMMON. Retrieved 2013-11-13.
- "Young i Professionals (YIPS)". YIPS. Retrieved 2013-11-13.
- IBM i at ibm.com
- IBM Systems IBM i Magazine
- IBM developerWorks: Articles, tutorials, and technical resources for IBM i users
- IBM i Wiki: A collaborative environment for the sharing of technical information related to IBM i
- IBM developerWorks Article: New to IBM i