In 1988, the AS400 was introduced, changing how people do business forever. But what exactly is the AS400, now known as IBM i, and what role does it have in a modern enterprise?
Lateral’s early history was actually in selling AS400 hardware before specialising in software development. By supporting the AS400 hardware and developing software for it we know a thing or two about the platform.
In this guide, Lateral explains the AS400’s history, functionality, and why technology has moved on. You’ll also discover the importance of modernising these types of systems and how Lateral helps keep your organisation relevant in today’s fast-paced world.
Read on to learn the following:
The AS400 is IBM’s mid-range server platform launched in 1988.
The AS400 system evolved from the popular System 36 and System 38 platforms. IBM designed these systems to be high-performing while still being easy to use. IBM’s goal when creating the AS400 platform server was to enable small and medium-sized firms to set up and operate their own networks themselves, removing the need for specialized training.
With this system, IBM offered a powerful and scalable system that the general public could quickly adapt to and use. It used two base processors, the B10 and B20, which were designed to blend into existing systems easily. This means that organisations and companies could use the AS400 system without the need to change everything they were already using.
In short, the AS400 changed how business was done and continues to play a significant role in major industries. It was a glimpse of how the future of modern offices would look, with information moving at the speed of light. Banking, manufacturing, insurance, and retail for ERP systems, such as MAAPICS and JD Edwards, still use modernised AS400 systems. Lateral specialises in legacy application modernisation, ensuring you can continue to use your current system for years ahead, extending the lifespan of your investment.
The History of AS400?
The history of the AS400 traces its roots to the System/3, a midrange computer introduced in1969. This computer performed punched-card processing on a 96-column card, which offered more information per card while requiring less space for card filing and hardware. It was created to replace punched card applications such as payroll, billing, and accounts receivables, among others.
Almost a decade later, in 1977, the first ERP systems began to appear on the System/34. These ERP systems started the shift from paper-heavy, individual, and disconnected systems to tightly integrated solutions for accounting, payroll, and inventory. IBM described it as “a family of desk-top display stations, printers, and a powerful central processor.”
In 1978, the System/38 was launched, and it was a significant leap forward in terms of computing power and the number of users who could access the system. It also featured an integrated relational database and microcode.
Ten years later, in 1988, the System/38 evolved into the AS400, a mid-range server platform with thousands of applications, from banking, insurance, inventory management, manufacturing, and retail.
IBM had two main priorities when creating the AS400 - high performance and ease of use. A notable feature of the AS400 was that it worked with all models and was also backward compatible with most System/36 and System/38 applications, allowing firms to upgrade their networks without replacing existing software. IBM ensured that the barriers to entry for the AS400 were low so firms could easily use and adapt the IBM AS400 to fit their needs.
The AS400 has evolved into iSeries, System i, and today, it is known as IBM i on Power Systems. The platform remains essential to many organisations that want a stable, scalable, and secure network.
Off-the-shelf healthcare software may not always meet the unique requirements of medical institutions. Custom software development ensures:
It combines an operating system, hardware, and applications into one system, making it easy to use and upgrade as needed.
The AS400 system has a built-in relational database that provides organisations with an efficient way to manage and process data even with multiple users.
The AS400 uses RPG, or Report Program Generator, an IBM-developed high-level programming language used to develop business applications and generate reports, such as inventory management and CRM software.
The system uses microcode, a translation layer that transforms a system’s instructions into actions for the physical hardware to perform. The platform uses System Licensed Internal Code (SLIC) as the microcode that bridges the software and the hardware.
Cybersecurity is top of mind for most modern organisations. Robust security features, including object-level security, authentication, encryption, and a built-in firewall are well-known features of the AS400. These features help protect business data and keep important information safe from cyberattacks
While the AS400 is reliable, scalable, and built to support multiple users, it is just like any other system that requires modern day software approaches to breathe new life into it. This is where Lateral comes in. Our services focus on helping organisations bring their legacy systems, like the AS400 into the modern age. With our help, we can transform your almost-outdated tech into a relevant and modern system that fits your needs.
Is the AS400 still relevant today? The short answer is it is probably time to move on.
The AS400 remains relevant in specific contexts, however, it faces significant and growing challenges due to its age, skills shortage, and complexity integrating smoothly with modern cloud-native architectures and digital transformation initiatives.
30+ years is very long in tech terms. There has been a fundamental shift away from the integrated, monolithic style the AS/400 originally championed. New projects rarely select IBM i as the platform; modern paradigms favour cloud platforms like AWS, Azure, or Google Cloud. Its relevance is increasingly tied to legacy workloads rather than new development.
Modernising a core system like AS400 can feel daunting, but with the right partner, it doesn’t have to be. At Lateral, we bring deep expertise in legacy system transformation, offering tailored strategies that minimise risk and maximise value.
Whether it’s rearchitecting your backend, building intuitive web interfaces over legacy logic, or gradually replacing ageing modules with modern applications, we guide you through. We’ve helped clients build responsive web portals, mobile apps, and real-time dashboards that sit atop or replace AS400 backends, while ensuring business continuity.
Our approach is pragmatic, not one-size-fits-all. If retaining parts of your AS400 still makes sense, we will modernise around it. If a full migration is the goal, we’ll help re-platform your core systems with confidence.
If you’re still running on AS400, now is the time to consider your future.
At Lateral, we specialise in transforming legacy systems into high-performing, future-ready platforms. Let’s discuss how we can modernise your AS400 to position your organisation for what’s next.
Ready to modernise your own AS400 system? Contact us today to learn how Lateral can help.
ERP applications manage essential business functions such as accounting, finance, and human capital management. IBM i (today’s AS400) is often used to run ERP systems such as MAAPICS, JD Edwards, and Infor.
It also supports financial applications, such as banking systems, credit card processing, and loan management services.
Organisations use various supply chain management systems on IBM i to optimize their supply chain. These systems manage logistics, order processing, and inventory management to develop the best process for their specific requirements.
Aside from these applications, IBM i is also used in insurance applications, warehouse management systems, healthcare information systems, and more.
2. How does AS400 work?The AS400 integrates software, hardware, and applications into one robust, scalable, and secure mid-range computer system. All types of organisations can use it, from small and medium-sized businesses to large enterprises.
Some notable features include the following:
3. Is AS400 still relevant today?
In some case, yes, but increasingly, only as a legacy system being kept alive by necessity, not by choice.
While many AS400 systems are still in operation, they often represent technical debt. Businesses continue using them because of long-standing integrations and critical business logic built over decades, not because they’re fit for today’s fast-paced, digital-first environment.
The platform's biggest hurdles include a critical shortage of developers and administrators, making support and evolution difficult. Integrating its traditional architecture with modern cloud platforms, APIs, and digital workflows presents significant technical and cultural challenges. Furthermore, overcoming the perception of being "legacy" technology hinders both modernization efforts and attracting new talent.
Lateral specialises in modernising legacy systems, including your AS400. Correctly upgrading and updating any system takes time, effort, and, most importantly, expertise. It’s best to work with a reliable and knowledgeable partner like Lateral to ensure your organisation gets what it needs. See how we modernised an AS400 system.
Ready to modernise your AS400 system? Contact Lateral today, and let us help bring your system forward to get you where you need to be.