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      Gain Valuable Answers to All Your AS400 Mainframe Questions

      AS400 mainframe
      • Are you seeking to leverage the power of the IBM AS/400 Mainframe for your organization?
      • But wondering if investing in mainframe applications is becoming outdated?

      Here’s an inside story: Mainframe AS400, despite being a 90’s brainchild, is very much alive and kicking – owing to its enduring reliability and adaptability.

      Curious to know more about IBM AS400 (Application System/400) and mainframe?

      In this extensive read, we’ve compiled answers to the top questions around AS400 mainframe system that frequently arise in the minds of AS400 users, developers, and decision-makers, like yourself.

      But first, let’s quickly revisit the history of AS-400 Mainframe. (Feel free to skip the history as you may already be familiar. But don’t skip the read as there is a lot about AS400 mainframes present & future, to unveil.)

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      Let’s begin.

      Dynamic History of AS 400 Mainframe (Skip if you’re already well-versed)

      Created on June 21, 1988, the AS400 system (An integrated system of hardware (AS/400) and an operating system (OS/400) was introduced to the world as a new family of easy-to-use computers.

      Alongside AS-400, you must have come across the term AS400 Mainframe. To clarify any confusion between the two, let’s delve deeper.

      Mistakenly perceived as synonymous, the two terms refer to the same computer system, but the key difference is AS 400 is a mid-range server and the latter is a high-end server.

      Regarding the AS400 IBM Mainframe system, please note that on April 7, 1964, IBM revealed its mainframe computer system known as System/360.

      Interestingly, this family of computers was developed to serve a wide range of scientific and commercial applications, from small to large.

      We hope this has cleared the clouds of confusion between the AS400 and AS/400 Mainframe.

      Wondering – “Is AS400 still used today?”

      While many businesses have moved their server systems to the cloud, the primary technology from the original AS400 is still widely used by multiple companies across industries. Over 39% of IBM i users report that they currently run 75%-100% of their core operations on IBM i – according to a survey of IBM i users.

      AS/400 continues to evolve and retains support for applications written even 30 years ago.

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      Is AS400 A Mainframe? Let’s Figure It Out!

      As per IBM, Mainframes are large-range data servers designed to process up to 1 trillion web transactions and simple calculations every day, in real-time, with air-tight security and reliability.

      The mainframe has a unique architecture and design that nurtures high-performance, high-efficiency computing tasks and mission-critical operations where downtime and data integrity are crucial concerns.

      If you are accessing modern business applications, know that you are indirectly interacting with the mainframe computer working behind the curtains to handle crucial functions.

      On the contrary, AS-400 is a mid-range server, not a mainframe (high-end server). Its unique architecture and operating system carve its niche in business applications, database management, and integrated solutions; a diverse set of tasks compared to traditional mainframes.

      AS/400 or AS400 Mainframe: Which Is Right for Your Business?

      There’s persisting confusion about AS400 and Mainframe because they belong to the same computer system. But they differ in various ways.

      Let’s look at the primary disparities between AS400 vs Mainframe to make an informed decision.

      Size and Power

      A) AS400

      It’s a commodity server undersized than a mainframe, meant to perform special tasks. It comes in small as well as rack-mounted computers.

      It boasts a powerful processor that efficiently runs small and medium-sized business operations.

      B) Mainframe AS400

      It’s a refrigerator-size server that can handle 1 trillion web transactions and simple calculations in a day, without compromising the security.

      Thousands of users can process large chunks of data effortlessly, making them suitable for enterprise-level critical operations.

      Cost Factor

      A) AS-400

      A typical AS400 system can range up to a couple of 10s of thousands of dollars.

      B) AS 400 Mainframe

      A typical mainframe system can go up to hundreds of thousands of dollars.

      User Capacity

      A) AS400

      The server supports limited users as it is meant to handle small-to-medium workloads, however, the users can scale the support up and down as per their needs.

      B) AS/400 Mainframe

      The AS400 mainframe computer can easily take up thousands of users and a massive workload while assuring fast and uninterrupted transactions per second.

      Business Utility

      A) AS 400 system

      Typically, the system is used to host business applications, manage databases, business analytics, and more.

      B) AS400 Mainframe System

      The mainframe performs thousands of transactions per second while accessing numerous resources. Mainframe runs critical functions, such as telecommunications or scientific research where dependability is the top priority.

      Let’s understand the AS400 vs Mainframe difference with the help of this illustration:


      Let’s say there is a retail chain in need of a robust inventory management system to manage the stock levels, purchase and sales data, and supply chain operations across their 1340 warehouses.


      The decision-makers choose to implement the inventory management system on the AS400 platform.


      AS400’s business applications and database management capabilities offered them the leverage required.

      Furthermore, the platform has enabled a seamless flow of data across the organization, with real-time inventory tracking, reporting and data processing advantages.

      Similarly, they are looking for an all-in-one solution to manage their entire financial transaction process across the 1340 stores.

      The business leaders of the company opt for the AS400 mainframe for its exceptional reliability, high processing power, and high storage capacity, serving many thousand users, while protecting the integrity of the inventory information.

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      What Is the Strategic Advantage of Investing in AS400 Mainframe In 2024?

      Here are the ground-breaking strengths that make the AS 400 Mainframe computer a precious asset in 2024:

      Dependable Reliability, Availability, and Serviceability (RAS)

      The AS400 mainframe system makers lay great emphasis on Reliability, Availability, and Serviceability (RAS), which plays a crucial role in data processing.

      It’s a boon for modern businesses that demand a rock-solid foundation for effortless operations and critical data processes.

      Robust Security

      Data is the oil of the digital economy.

      From customer information, billing and payment information, social media activities, and whatnot. This critical data must be managed, controlled, and protected from cyber villains while using it efficiently.

      The mainframe AS400‘s security capabilities protect the data while allowing multiple authorized users to access the data without any hassle.

      Assured Scalability

      Thanks to its robust hardware and software capabilities, as your business grows in terms of partners, customers, and staff, you need not worry about the scalability of the mainframe.

      It’s a reliable technology that evolves with your business needs, while you focus on the business growth. This feature has also enabled many corporations to reap the benefits of reduced total cost of ownership.

      Compatibility Across Generations

      Some mainframe applications were written ages ago while some were created yesterday, and the beauty of the AS400 mainframe system boasts the ability to adapt both, ensuring compatibility across generations.

      What Does a Mainframe Look Like?

      Traditional mainframes needed a lot of physical space (even dedicated rooms) and were very noisy. However, modern upgrades have led the mainframe computers to fit in almost all environments.

      How Does the AS400 Mainframe System Work?

      One of the popular questions asked is – how does the mainframe system work?

      Let’s demystify its unique engineering:

      Versatile Operating Systems

      The mainframe is designed to run on versatile operating systems such as Linux or Windows alongside special operating systems such as IBM z/OS, and software that reaps the benefits of unique hardware capabilities.

      High Transaction and Data Processing

      The mainframe AS400 excels in supporting a massive number of concurrent transactions and data processing, along with built-in capacity on demand, and built-in shared memory for direct application communication.

      Air-Tight Security

      The mainframe computer offers the best security blanket including built-in cryptographic cards and innovative software. Its users can perform over 1 trillion transactions without breaking a sweat.

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      Resilience and Redundancy

      Mainframe resiliency is engineered with multiple layers of redundancy for every feature, from CPUs, cryptography modules, power supplies, cooling, etc. while possessing a stronghold in the ever-evolving landscape of technology.

      Who Still Uses AS400 Mainframe System in 2024?

      Thinking IBM iSeries Mainframe is done and dusted?

      Instead, many companies are still using the mainframe they invested in years ago, and even investing in more.

      It builds a solid foundation for modern businesses such as government organizations, financial institutions, healthcare companies, and many others.

      Read on to know – “Who still uses AS400 system?”

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      Finance and Banking

      Over 44 of the leading 50 banks continue using IBM Z mainframe, according to IBM.

      • Atm withdrawals
      • Transaction processing
      • Regulatory compliance
      • Online account updates
      • Customer account management


      The IBM AS/400 mainframe is used by the top 10 insurers across the globe, according to IBM.

      • Set prices
      • Claims processing
      • Administer policies
      • Invest in the right markets
      • Conduct actuarial and risk analysis


      Aircraft manufacturers highly depend on mainframe computers for the timely arrival of planes and people, as per IBM.

      • Ticket reservation systems
      • Handle intricate operations
      • High reliability and continuous service
      • Protection of sensitive passenger data


      23 out of 25 biggest United States retailers continue to use mainframe, says IBM.

      • Highly efficient transaction processing
      • Complex inventory management
      • Point of Sale (POS) systems
      • E-commerce integration
      • Production planning
      • Quality control

      What are the Features of the Mainframe?

      The AS400 Mainframe computer boasts a powerful range of features including:

      Multiple Input/Output (I/O) Cards

      The mainframe AS400 is equipped with 160 I/O cards to ensure redundancy and fault tolerance. The card acts as a replacement if another card is malfunctioning.

      Impressive Storage Capacity

      The system has massive storage capacity, allowing users to process large volumes of data, get it interpreted and after processing, receive perfect answers.

      Two Powerful Processors

      One of the special features of the mainframe AS400 is that it has 2 different processors – The primary processor and The System Assistance Processor / SAP. Both the CPUs possess particularly designed cores for enhanced productivity.

      Uninterrupted Functioning

      Typically, users have to pause the system to perform different crucial tasks like updating software on the system which can cause productivity loss.

      In the case of a telecommunications company, it could even cause panic among the customers because of the inability to process. The AS400 mainframe system is developed to function effortlessly all day and all night long for a worry-free experience.

      Advantages of More Than 1 Operating System

      The AS/400 mainframe users enjoy the luxury of hosting various operating systems on a single mainframe. For instance, users can effortlessly host and use z/TPF in coexistence with z/OS.

      Fault-Tolerant Computing

      This is a special feature of the AS400 Mainframe computer which ensures that a large volume of data transported from or to a system doesn’t hurt its ongoing operations.

      Moreover, the system ensures error-free data transfer while moving massive data inside the database. It manages the massive data, processes, and applications, comfortably.

      Clustering Technology

      AS400 mainframe computer supports Parallel Sysplex clustering, a feature that promotes a bunch of up to 32 IBM z/OS systems to be connected as a unified computing system.

      The exceptional function is that even if 1 system crashes, the work will be continued and completed on the next live system without any performance damage.
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      What are the Challenges Mainframe As400 Faced in the 21st Century?

      Along with benefits, the limitations are an integral part of the AS/400 mainframe.

      Challenges Mainframe As400

      Let’s take the plunge.

      Mainframe Applications are Majestic Elephants That Are Hard to Catch

      Updating and enhancing the extensive legacy mainframe applications pose a serious challenge due to a lack of documentation and expertise.

      Furthermore, the high interdependency of applications makes it prone to downtime and complicated entanglement.

      Limited Automation and Increasing Expense of Testing

      As against the modern development pipelines, limited automation and soaring expense pose a testing challenge in AS 400 mainframe system applications. Additionally, there is no scope for individual component testing because of the complex physical hardware dependence.

      Mainframe Development Requires an Exclusive Stage

      As opposed to the modern software development pipelines that simplify changes with automated testing, the AS400 mainframe computer with its dedicated stage calls for a structured process to mitigate the risk.

      Scarcity of Younger AS400 Mainframe Developers

      Over 60% of mainframe professionals have reached the final chapter of their careers and very few computer science graduates are replacing them.

      While the developers are popularly advancing in modern languages, very few curious minds are interested in understanding the depths of COBOL, RPG, and procedural code.

      Mainframe Maintenance Is Very Costly

      The mainframes aren’t cheap.

      Many participant companies reported an average annual spending of $65 million simply on its maintenance, as per the 2022 mainframe modernization business barometer report.

      This doesn’t mean you bid farewell to the decades-long-companion — AS400 mainframe system.

      A proficient and seasoned AS/400 application development partner comes to your rescue to modernize your mainframe applications, derive value from your current systems – ensuring a future-proof pathway forward.

      Is AS400 Mainframe Computer Still Relevant in the Modern Business Landscape?

      Despite their decline due to the emergence of modern technologies like the Cloud and low-cost x86 servers, the mainframe continues to make strides in the world of IT infrastructure as emphasized below.

      • The global mainframe market is projected to grow and reach a startling figure of $2.90 billion by 2025, says Allied Market Research
      • 67 of Fortune 100 enterprises continue to use mainframe for their most crucial business functions, as per IBM.
      • Over 74% of respondents believed that the mainframe has a long-term practical use as a strategic medium for their enterprises, as per a Deloitte survey

      With these numbers at your disposal, it’s evident that the ‘big iron’ is here to stay unless the computers start baking cakes.

      What is the Working of Modern AS400 Mainframe?

      Unlike legacy mainframes, modern IBM AS400 mainframes have a sophisticated architecture of a central processor complex (CPC) combining specialty processors designed to serve unique purposes.

      The modern AS400 IBM Mainframe comprises crypto, network, compression, and storage cards with their own memory and processors.

      Furthermore, it has System Assist Processors (SAP) to accelerate the data transfer between the operating system and the input/output devices and processors for running Linux, Java, and other workloads.

      This sophisticated architecture enables the modern IBM AS 400 Mainframe to function at its peak efficiency while handling high throughput volumes.

      The modern AS400 Mainframe solutions are also designed to support 21st-century cutting-edge technologies like artificial intelligence, big data and analytics, quantum computing, cloud computing, and more.

      Can Cloud Replace the Mainframe AS400?

      The community of naysayers may think the cloud has taken over the mainframe. On the contrary, the cloud is just a polished way of offering the same functionalities that mainframe has been offering for ages.

      It won’t be an exaggeration to say that mainframe computers are the real clouds.

      When you doubt that modern technology will wipe out the existence of mainframe, consider these statistics by IBM:

      • 4/5 Top Airlines
      • 8/10 Top Insurers
      • 7/10 Top Retailers
      • 8/10 Telecom Companies
      • 67/100 Fortune Companies
      • 45/50 Banks continue relying on the AS/400 mainframe.


      Because it is secure, scalable, and dependable — that has set it apart from modern tech for the past many years and will set it apart for the next many.

      What are the Future Trends of AS400 Mainframe Technology?

      Here is a sneak peek into the future of the AS400 mainframe.

      Big Data Analytics

      Mainframes are likely to play a key role in the future of big data. With the growing importance of data, enterprises will require a potent platform such as Mainframe, to process and analyze it faster, with accuracy.

      AI & ML

      Along with Big Data Analytics, the mainframe has joined hands with Artificial Intelligence (AI) and Machine Learning (ML) to train and deploy models.

      AS/400 Mainframe with its integral capability to support the requirements will be an ideal choice, making it a vital part of the future.

      Integrative Systems: One-Stop Shop for IBM i/AS400 Services

      As you are armed with the nitty-gritty of the AS400 mainframe, its history, present, and possible future, benefits, and challenges, you are all empowered to make the decision by yourself.

      Still have queries?

      We, at Integrative Systems, are a team of AS/400 professionals with 25+ years of development experience. Reach out to us at [email protected] with your plans, doubts, or ideas for a FREE consultation and we will help you turn them into solutions.

      Our Range of AS400 Services include –

      Dig deeper: 52 Types of IBM i AS400 Services Offered by Integrative Systems

      Frequently Asked Questions about AS400 IBM Mainframe and Mainframe Applications

      Is AS400 a Server or Database?

      AS400 is a mid-range server released in 1988 by IBM and has undergone multiple rebranding initiatives. In 2008, it was named IBM Power Systems. AS/400 has a dedicated database – DB2 employed by organizations to store and retrieve data from critical software applications.

      What is AS400 in Mainframe?

      AS 400 is a mid-range server and shares similarities with the AS400 Mainframe, a high-end IBM server. AS/400 is widely used by small and medium-sized businesses along with large-sized businesses, whereas the AS400 IBM mainframe is widely used by large enterprises with demand for high-processing power and security.

      Who is an AS400 Mainframe Application Developer?

      AS/400 Mainframe Applications developer or a programmer is responsible for:

      • Developing applications on the IBM iSeries mainframe platform
      • Writing, testing, and debugging code
      • Implementing best practices
      • Performing maintenance and troubleshooting tasks
      • Providing training and technical support to the end-users
      • Updating and enhancing the AS/400 mainframe applications

      Does IBM Still Make Mainframes?

      There was a time when the mainframe market was dominated by multiple players. Today, IBM is the only mainframe manufacturer conducting business at scale.

      Will AS400 Mainframe be Replaced?

      Over 92% of participants expressed confidence in the mainframe’s long-term growth prospects and suitability for managing new workloads, as per a BMC Survey 2023. This affirmation means that despite the emergence of new technologies, the AS400 Mainframe shall continue to stand strong and will not be replaced anytime soon.

      Do People Still Buy AS400 IBM Mainframe?

      AS/400 Mainframe remains a cornerstone of enterprise computing, used by large enterprises and Fortune 500 companies to handle critical tasks such as performing large-scale transaction processing, managing terabytes of information in databases, tackle large-bandwidth communication, etc.

      Who Still Makes Mainframe Computers?

      Currently, IBM is the biggest manufacturer of mainframe computer systems. With products like AS400 Mainframe, IBM continues to lead the charge of this iconic domain.

      What is a Good Example of a Mainframe Computer?

      IBM zSeries is one of the best examples of a mainframe computer in 2024.

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