The question "is as400 the same as iseries" surfaces frequently among IT professionals and business owners evaluating legacy systems. It stems from a common confusion regarding IBM's nomenclature for their midrange server platform. Essentially, the terms refer to overlapping, but distinct, technological eras and marketing labels within the same robust hardware and software ecosystem.
Decoding the IBM Midrange Lineage
To clarify the relationship between AS400 and iSeries, one must look at the historical evolution of IBM's midrange computers. The AS400, which stands for Application System/400, was the groundbreaking architecture launched in 1988. It was designed as an integrated system, combining the operating system, database, and hardware into a single, tightly optimized unit. This holistic approach was revolutionary, aiming to reduce the complexity typically associated with IBM mainframe environments.
The Evolution to iSeries
Following the introduction of the IBM PowerPC processor, the platform was rebranded to reflect its new technological foundation. This led to the introduction of the iSeries in 2000, which marked a significant shift in marketing and underlying architecture. While the iSeries retained the core principles of the AS400—such as the integrated operating system now known as IBM i—it leveraged the power and scalability of the Power processor architecture. Therefore, asking is as400 same as iseries ignores the generational leap in hardware that occurred between the two labels.
Technical Continuity and Divergence
From a software perspective, the transition was designed to be seamless. Applications developed for the AS400 generally run without modification on the iSeries and its successors. This continuity ensures a high level of protection for a company's software investment. However, the hardware divergence means that an iSeries server cannot run the original OS/400 software designed specifically for the AS400's instruction set. The question is as400 same as iseries is best answered by recognizing that iSeries is the modern successor, not an identical twin.
AS400: Refers to the original 1988 architecture with its proprietary instruction set.
iSeries: Represents the PowerPC-based evolution starting in 2000, maintaining compatibility at the application level.
IBM Power Systems: The current hardware brand that continues the iSeries legacy with enhanced performance and cloud integration.
Modern Context and Relevance
Today, the iSeries brand has been folded into the broader IBM Power Systems family, often causing further confusion for those unfamiliar with the lineage. When discussing is as400 same as iseries, it is crucial to understand that the iSeries was a bridge between the old and the new. Modern IBM i runs on Power hardware and offers features like cloud integration, open-source support, and advanced virtualization that were unavailable on the original AS400 platform.
Why the Confusion Persists
The enduring nature of IBM i software means that many businesses still operate on systems originally called AS400, even if the current hardware is technically an iSeries or Power System. The term AS400 has become a colloquialism for the entire IBM midrange environment, much like "Kleenex" is used for facial tissue. This linguistic shorthand contributes to the persistent question is as400 same as iseries, as users interact with the interface rather than the hardware specifications.
Conclusion on Terminology
While the underlying technology has advanced significantly, the core philosophy of integration and reliability established by the AS400 remains central to the IBM i platform. Understanding that iSeries is the hardware successor to the AS400 helps clarify the relationship. For businesses, the critical factor is the continuity of the operating system and applications, allowing for a smooth evolution without the need for costly rewrites, even as the hardware generations change.
