IBM i
| Main Menu of IBM i 7.1, shown inside a TN5250 client | |
| Developer | IBM | 
|---|---|
| Written in | C++, C, PL/MI, Java, Assembly language, Modula-2, PL/MP | 
| OS family | IBM CPF | 
| Working state | Current | 
| Source model | Closed source | 
| Initial release | August 26, 1988 | 
| Latest release | 7.6 / April 18, 2025 | 
| Marketing target | Minicomputer, midrange computer and enterprise server | 
| Available in | English | 
| Update method | Program temporary fixes (PTFs) | 
| Package manager | RPM and YUM for open source packages | 
| Platforms | IBM AS/400, IBM Power Systems | 
| Kernel type | shares many Microkernel (SLIC) and Virtual machine (TIMI) design philosophies | 
| Default user interface | Text-based user interface | 
| License | Proprietary | 
| Preceded by | System Support Program, Control Program Facility | 
| Official website | ibm | 
IBM i (the i standing for integrated) is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS in 2004, before being renamed a second time to IBM i in 2008. It is an evolution of the System/38 CPF operating system, with compatibility layers for System/36 SSP and AIX applications. It inherits a number of distinctive features from the System/38 platform, including the Machine Interface which provides hardware independence, the implementation of object-based addressing on top of a single-level store, and the tight integration of a relational database into the operating system.