Iseries

iSeries refers to IBM’s family of midrange computer systems that has carried several names over its history. The line began as AS/400 in 1988, was later marketed as iSeries from 2000, and then rebranded as System i in 2001. Since 2008 the platform has been marketed primarily as IBM i running on IBM Power Systems, with the branding iSeries appearing mainly in historical or colloquial contexts.

Hardware and software foundation

iSeries systems are built on IBM Power processor technology and are designed for medium-sized businesses requiring reliable, integrated computing environments. A core feature is IBM i, the operating system that evolved from OS/400 and includes a tightly integrated database (DB2 for i), security, and system services. The architecture emphasizes ease of administration, high availability, and consolidated development and execution environments.

Programming and ecosystem

IBM i supports multiple programming languages, including RPG, COBOL, CL (Control Language), C, C++, Java, and PHP. It offers a unified development experience with integrated DB2 for i, enabling consolidated application logic, data, and user interfaces. The system supports modern interfaces and connectivity through APIs, JDBC/ODBC, and web services, as well as batch processing for enterprise workloads.

Deployment and virtualization

Power Systems running IBM i support virtualization through PowerVM, including logical partitions (LPARs) and resource management features that enable multiple isolated environments on a single physical server. IBM i emphasizes backward compatibility and robust performance for line-of-business applications, batch jobs, and critical financial and manufacturing workloads.

Current status

While the iSeries branding is largely historical, IBM continues to develop and market IBM i on Power Systems. The platform remains in active use in many organizations, valued for its integrated DB2 database, reliability, and integrated development environment.