IBM AS/400, now known as IBM i on Power Systems, is one of the most robust and reliable enterprise computing platforms in the history of information technology. Introduced in 1988 by IBM, the AS/400 (Application System/400) revolutionized business computing by integrating hardware and software into a unified system. Over the decades, despite advancements in technology and the emergence of cloud computing, AS/400 continues to hold relevance in many mission-critical environments across industries such as banking, manufacturing, insurance, healthcare, and logistics.
This article by Multisoft Virtual Academy delves into the history, architecture, components, key features, modern relevance, and future outlook of the IBM AS/400 Online Training platform.
The AS/400 system was introduced by IBM in June 1988 as a successor to its System/36 and System/38 midrange computers. The goal was to offer a reliable, scalable, and secure platform for small and medium businesses (SMBs) and departments within large enterprises. Over the years, IBM continuously improved the AS/400 architecture. Some key milestones include:
Despite name changes, many professionals still refer to it as IBM AS/400 training, reflecting its lasting impression on enterprise computing.
The AS/400 architecture is unique and one of its biggest strengths. It combines:
a. Integrated Operating System: IBM i
Formerly known as OS/400, the IBM i operating system is a fully integrated, object-based OS. Unlike traditional UNIX or Windows systems, IBM i treats everything—including files, programs, and devices—as objects, enhancing stability and security.
b. Technology Independent Machine Interface (TIMI)
One of the revolutionary features is TIMI, which abstracts the application from the hardware. This means programs compiled decades ago can still run on modern Power Systems without recompilation. It ensures upward compatibility, which is rare in the IT industry.
c. Single-Level Store Architecture
AS/400 systems use a single-level storage model that combines memory and disk storage into a single addressable memory space. This simplifies memory management and enhances performance.
d. Hardware – IBM Power Processors
Modern IBM i systems run on IBM Power processors, known for high reliability, performance, and RAS (Reliability, Availability, and Serviceability) capabilities. Power Systems can run IBM i, AIX (UNIX), and Linux side-by-side.
a. DB2 for i
The AS/400 includes an integrated relational database—DB2 for i—deeply embedded in the OS. Applications do not need separate database installations, and the integration ensures high performance and security.
b. Programming Languages
Common languages used on AS/400 include:
c. Work Management
IBM i uses a subsystem approach to manage workloads, isolating processes to optimize performance and resource management.
d. Security
The system is known for robust security features:
The IBM AS/400, despite being introduced over three decades ago, continues to maintain its relevance in today’s fast-evolving IT landscape due to its unmatched stability, reliability, and cost-efficiency. One of its greatest strengths lies in its ability to provide near-continuous uptime, with many businesses reporting over 99.999% availability—making it ideal for mission-critical operations in banking, retail, healthcare, and manufacturing. Its robust security model, built directly into the operating system, ensures object-level access control, audit capabilities, and integrated encryption, offering significantly better protection compared to many modern open systems. The AS/400's backward compatibility is another major advantage; applications developed in the 1980s and 1990s still run seamlessly on today’s IBM i systems without the need for recompilation, saving organizations significant time and money on redevelopment.
Moreover, its integrated DB2 database, combined with a unified hardware and software architecture, minimizes the need for external components and reduces overall system complexity. This not only lowers the total cost of ownership (TCO) but also simplifies administration and maintenance. Additionally, IBM has kept the platform up to date by introducing support for modern programming languages like Python, PHP, and Node.js, as well as web services, APIs, and cloud integration, enabling businesses to bridge legacy systems with modern digital tools. With features like IBM Navigator for i, enhanced SQL engines, and cloud-hosting capabilities, the AS/400 certification has transformed into a hybrid-ready platform without sacrificing its original strengths.
For enterprises seeking reliability, long-term application support, and secure, integrated environments, AS/400 (now IBM i) continues to be a powerful and future-ready choice. Its enduring legacy is a testament to IBM's strategic innovation and the platform's fundamental design principles that prioritize business continuity and operational excellence.
a. Open-Source Support
Recent versions of IBM i include support for:
These allow integration with modern development workflows and CI/CD pipelines.
b. IBM Navigator for i
A modern web-based GUI tool for system administration, replacing green-screen-only management.
c. Cloud Readiness
IBM i can now be hosted in the IBM Cloud, Microsoft Azure, Google Cloud, or private cloud, offering hybrid deployment models.
d. SQL Enhancements
DB2 for i has evolved to include SQL Query Engine (SQE) for enhanced performance, stored procedures, and integration with BI tools.
The AS/400 has been used extensively in:
Its reliability and ease of integration have made it a favorite for industry-specific applications.
Despite its strengths and longevity, the IBM AS/400 platform faces several challenges and criticisms in today’s modern IT environment. One of the primary concerns is the shrinking talent pool—as many seasoned AS/400 professionals retire, there’s a noticeable shortage of new developers skilled in legacy languages like RPG and CL, making system maintenance and development increasingly difficult. Another significant issue is the dated user interface; many AS/400 applications still rely on the green-screen 5250 terminal, which can be intimidating and inefficient for users accustomed to modern graphical or web-based interfaces. This often leads to resistance from younger IT professionals and end-users, impacting overall productivity and adoption. Additionally, businesses face pressures to modernize and align with digital transformation strategies, and while IBM i supports integration with modern tools, the process can be complex, costly, and time-consuming—especially for large, monolithic legacy applications. There’s also a perception problem: many stakeholders still view AS/400 as outdated or obsolete, overlooking the platform’s continuous evolution and modern capabilities.
Furthermore, while the system is known for its reliability, it can be challenging to integrate with newer technologies, such as microservices, containers, or AI/ML tools, without substantial customization or third-party middleware. Lastly, the licensing and upgrade costs associated with IBM hardware can be high compared to commodity x86 hardware or cloud-native solutions, deterring some businesses from investing further. These factors contribute to the debate around whether to retain, modernize, or replace AS/400 systems, making it critical for organizations to assess long-term IT strategy alongside operational needs.
When comparing IBM AS/400 to modern alternatives such as Windows Server, Linux-based systems, or cloud-native platforms, several distinctions become evident. The AS/400 excels in stability, offering unparalleled uptime and fault tolerance, which is especially critical for industries where system failures can result in significant losses. Its integrated architecture—with a built-in database (DB2 for i), operating system (IBM i), and development tools—reduces complexity and lowers total cost of ownership. In contrast, modern alternatives often require multiple software components and third-party tools to achieve similar functionality, which can introduce compatibility and maintenance challenges. Security is another key differentiator; AS/400 systems come with object-level security and audit capabilities embedded at the OS level, whereas newer platforms typically rely on layered security models that may be more vulnerable to breaches. However, modern alternatives offer advantages in scalability, user interface design, and developer availability, supporting a wide range of programming languages and frameworks. They also provide seamless integration with DevOps pipelines, containerization, and AI/ML workloads—areas where AS/400 still lags without extensive customization. While AS/400 is ideal for reliability and long-term application support, modern platforms offer flexibility, agility, and faster innovation cycles, making the right choice highly dependent on business needs and IT strategy.
Organizations running AS/400 today often follow one of these approaches:
The IBM AS/400 platform, with its legendary stability, integrated architecture, and business continuity strengths, remains a critical pillar in enterprise IT. While the name AS/400 may no longer be official, the system it represents has evolved significantly and continues to power key business processes around the world. For organizations that rely on security, uptime, and cost-effective computing, IBM i on Power Systems is not just a legacy—it is a strategic asset. The challenge lies in leveraging its strengths while embracing modernization and integration to meet the demands of today's digital business landscape. Enroll in Multisoft Virtual Academy now!
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12 Jul 2025 | 03 Aug 2025 | 24 | 06:00 PM - 09:00 PM | Sat, Sun | |
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