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IBM application modernization is a way to transform monolithic legacy applications into cloud-based alternatives. It helps maintain agility and reduce costs.


IBM Application Modernization: The Future of Legacy Systems Optimization

Posted by Angela Davis on March 29, 2023
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Software development is an ever-evolving field with a continual need for innovation. At a certain point, applications and software become outdated and stop serving users in the way they were intended.

Instead of replacing these legacy applications, it’s possible to move or integrate them into modern infrastructure such as a cloud platform. 

Below are just some of the reasons why you might modernize your legacy systems, software, or applications:

  • Easy and secure data management
  • Improved reliability and scalability for rapid growth
  • Streamlined deployment of apps
  • Compliance
  • Breaking down silos
  • Improved resiliency and security

For IBM computer systems, IBM application modernization means apps can continue to serve the needs of your business. 

Let’s discover what it’s all about.

Understanding IBM i and AS/400 modernization

IBM i or AS/400 is a system for building business applications. While it’s not in itself a monolithic architecture, many of the applications developed on it have become so in the years since its launch. This has made modernization necessary to continue using these legacy applications while ensuring maximum efficiency, security, and agility.

Happily, this computing platform allows for flexibility and continual modernization in terms of application development and testing, as well as licensing. Modernization simply means using tools and services to upgrade existing applications, leading to a more modern technology ecosystem. You might implement this as part of a digital transformation of your IT infrastructure.

This process is also known as AS/400 or IBM i modernization in place, particularly with reference to application servers. AS/400 systems are integral to mission-critical software for many businesses, as they store large amounts of valuable information (as well as core business logic for running enterprise apps).

That’s why modernizing applications based on the IBM i AS/400 operating system is generally managed with a phased approach for minimum disruption to business-critical functionality. Modernization techniques include testing and user-oriented design processes.

Now, let’s look at the difference between the IBM mainframe and AS/400.

Software coding example.

Image source

Understanding IBM mainframe modernization

While IBM i or AS/400 is a mid-range server, an IBM mainframe (like those from IBM Z systems) is a high-end server used to store large amounts of data and run centralization applications. First produced in 1952, these highly complex systems have undergone continual modernization to the present day. 

IBM mainframe modernization in place is the process of integrating and enabling large computer systems and apps with up-to-date software. It allows entire business systems to enjoy improved longevity and handle higher workloads.

Alongside a longer shelf life, the modernization of IBM mainframes can provide:

  • Improved compatibility with cloud-based systems
  • Improved user experience and compatibility with browsers
  • The ability to communicate effectively with other systems and applications (modern or legacy)
  • Easy cloud adoption (such as hybrid architecture) 

Ultimately, the goal of IBM application modernization is to optimize legacy systems—which may contain decades of data and vital business processes—so they remain functional and compatible with the new technology you introduce.

Modernizing mainframe-based applications is a critical element in successful hybrid cloud strategies. It allows  decades of data and vital business processes to be turned into the best competitive asset an organization can have by leveraging, opening, and exposing it. This makes the modernization process crucial for business survival.  

It also allows for greater speed and efficiency when rolling out consumer applications. If customers/clients are using your app, you will need to fault-proof (as far as possible) your software and ensure all data—including metadata—is secure. Modernization allows for easier deployment of applications so you can stay on top of customer expectations.


Why OpenLegacy is advantageous for IBM legacy systems modernization

It’s vital to choose the right tools and processes for legacy modernization because of the potential consequences of data and functionality loss. IBM offers its own solutions, such as IBM Garage, Z/OS Connect, and IBM Cloud Paks, but these are dedicated to IBM systems only. They’re also limited to specific servers and IBM server users/developers. As a result, they lack a more holistic view of the organization and its users and developers. 

Enter OpenLegacy. OpenLegacy is a cloud-native platform that bridges the gaps between legacy systems and apps and new systems and apps, using APIs and data-driven integration policy to do this. 

OpenLegacy is beneficial for IBM legacy systems modernization because it's native to all legacy systems, designed to handle multiple systems, and adaptive to any modern or cloud target architecture. Because of this, its features minimize disruption to existing business technology and processes. It can be deployed on-site at your premises, in the cloud for reduced hardware costs, or as a hybrid system.

The primary methods to consider for IBM legacy systems modernization are the following (both of which can be easily achieved with OpenLegacy):

  1. A phased approach. This method is less risky and more cost-effective than the big-bang approach and involves rolling out legacy systems integration gradually. You can do this for one or more processes simultaneously and by department, location, or whatever suits you best.
  2. The parallel method. This is where you implement a new system while still running your legacy systems. Using hybrid integration reduces risks and complexities significantly and is non-intrusive.

In contrast to other modernization processes or alternatives, OpenLegacy doesn’t require changes to your mainframe or IBM i systems. These can be modernized with minimal disruption to business processes or operations, and changes leave the basic functionality of the system intact. 

They also occur outside the modern environment, removing the need for intrusive alterations to legacy applications. 

The upsides of OpenLegacy include:

Simplified integration

When legacy applications don’t easily communicate with new software, it can be difficult or impossible to integrate different apps and modernize business systems. 

However, OpenLegacy’s native connectivity to any legacy system allows you to build user-friendly integrations automatically through the front-end interface using a no, low, or full code methodology of your choice in any modern language. Mainframe applications don’t need to be changed for its integration. 

This provides a simpler integration experience and maintains useability with easy testing and maintenance. 


Example of data analytics

Image source


Your application systems, including legacy systems, contain large sets of metadata, which provide vital information about other data in your applications.  

OpenLegacy’s integration and application modernization platform is able to read multiple types of metadata, including COBOL, PL1, and RPG code and files such as PCML, VSAM, etc. This means it can be applied to many types of legacy systems within a business, streamlining your apps and bringing them up to scratch. 

Easy to maintain

OpenLegacy Hub platform is consistent in applying the same integration and modernization patterns for any legacy systems, including IBM mainframes and midrange applications such as IBM i (AS/400). It generates the low or full code of your choice (C#, .Net, Java, etc.) to run your applications, avoiding additional application service or runtime layers known as “middleware”, which can complicate maintenance processes. 

OpenLegacy essentially creates a repository of your assets, providing a modern representation of your legacy assets in one place with versioning, so you can share, reuse, and modify them at any time. It also has templating for your standardization of choice. 

OpenLegacy technology can also operate in design time, generating standard APIs and microservices, Kafka, MQ, gRPC, etc. directly from core systems to be deployed anywhere and in multiple target environments. Hence, with only the necessary code and functionality in place and without duplicating or replicating business logic, software applications can be streamlined without the need for excessive code or proprietary run time. 

Cost-effective integration

Certain methods of integration or app modernization require a specialist team to implement the right code and user interface. While this may be the best option for certain industries, it can quickly become expensive and cumbersome. 

OpenLegacy Hub platform, especially for IBM modernization, is cost-effective as it relies on automated API generation, allowing different parts of the system to communicate with one another as well as with other applications in your ecosystems. 

The program parses metadata from your legacy system and generates related APIs, microservices, and other endpoints. All services generation and platform usage can be handled by a single developer with no proprietary knowledge and with no need for specialized legacy system skills or know-how.

On average, OpenLegacy delivers a 75% lower total cost of ownership (TCO) compared with traditional modernization methods. 

Fast services performance

In the absence of “middleware” and proprietary run time, your legacy systems (including IBM mainframe and IBM i), APIs, and microservices are in direct communication with one another. Without this interference and with a direct connection, OpenLegacy enables faster performance of your services than traditional application modernization. 

Essentially, the OpenLegacy methodology enables you to de-layer your architecture and use smart caching mechanisms, resulting in simple, fast, and effective service operations. This improved performance translates into easier deployment to consumers or across your team, allowing for improved productivity and working efficiency and a better user experience.

DevOps ready

DevOps is becoming increasingly popular with software development teams as a set of practices and values that allow businesses to deliver high-quality, high-velocity software products with greater efficiency than traditional software development methods. 

OpenLegacy enables easy alignment and integration with DevOps principles and pipelines. When your mainframe or IBM i applications transition from monoliths to microservices and generate microservices architecture—leveraging containers, Kubernetes, and AWS—it becomes easily deployable for efficient testing and maintenance. 

The simple, clean interfaces offered by OpenLegacy’s integration and modernization platform allow developers to test systems without assistance from mainframe development teams. This speeds up DevOps pipelines and the software development lifecycle.

Multiple deployment options

OpenLegacy’s APIs, microservices, functions, and other endpoints can be deployed in any target environment and across various platforms, including on-premises, for direct access to your architecture. Alternatively, it can be deployed over the cloud (including private cloud, public cloud, and multi-cloud platforms), reducing the need for hardware costs and space. This is excellent news for industries moving toward hybrid or remote working. 

Your updated core, IBM, and legacy systems can even be deployed as a hybrid system with minimal intrusion and/or changes to existing applications. You can make use of popular open-source tools for hassle-free deployment too.

OpenLegacy enables you to deploy Java, .Net, C#, Node.js, Python, and microservice-based APIs for internal and external integrations and serverless functions, or create a low-code/no-code service and deploy it on RedHat OpenShift, VMware, Anthos, etc.

Application modernization tools market revenue worldwide from 2018 to 2027

(in billion U.S. dollars)

Data sourced from Statista


OpenLegacy: The key to IBM legacy systems and applications modernization

OpenLegacy has advanced features to help you unlock the potential of IBM legacy systems and applications modernization. With solutions for every industry, including finance, insurance, retail, manufacturing, telecommunications, and governments, you can produce additional application services without changing the underlying system, avoiding an increase in technical debt.

Through modernization with OpenLegacy, your IBM i AS/400, mainframe, or other legacy and core systems will be flexible, cost-effective, easy to maintain, and deployable on and in multiple platforms and cloud environments. OpenLegacy is also DevOps-ready, speeding up your software development pipeline and adding business value. This enables maximum optimization without disrupting operations.

Start your legacy application modernization and legacy systems integration journey now with the help of OpenLegacy.


FAQs about IBM application modernization

What is IBM i / AS/400?

IBM i / AS/400 is an application operating platform targeted toward small and mid-sized businesses. Sometimes called a “mid-range server”, IBM i (also referred to as AS/400) provides infrastructure for running apps and storing data for those who don’t require the capacity of a mainframe. 

While an IBM mainframe operates as one large system, an IBM i or AS/400 system is an isolated piece of technology. 

What is an IBM mainframe? 

An IBM mainframe is hardware, systems, and architecture that are used for running apps and software systems. Also known as a “high-end server”, it powers centralized application operations and stores large amounts of data.  

IBM mainframes are popular with larger organizations because they’re powerful, reliable, and secure. They’ve been in use for longer than most other types of application architecture and are generally viewed as dependable and safe.  

In contrast to an IBM i or AS/400 system, an IBM mainframe is formed from many interacting parts, which create a gargantuan processing system.

How do you modernize an IBM i application?

IBM i is a mainstay of application systems but was not designed to interact with so many other technologies in business ecosystems due to its age. Ergo, it sometimes requires modernization to allow the introduction of modern technologies and cloud functionality. 

Two of the main ways you might go about IBM i (AS/400) application modernization are:

  • Updating useability. You can modernize applications by improving the user-end capabilities of your software. For example, updating your green screens (or “re-facing”) toward a browser-based user experience model or exposing its functionality via APIs and microservices.
  • Updating development. Another common modernization method is to adapt the way in which you approach software development, typically by adopting new development or integration tools such as OpenLegacy or updating an existing report program generator (RPG). 

How you modernize your apps will depend on what capability you need from your software, your software development capacity, and your existing infrastructure. 

What are the two most common examples of application modernization?

IBM legacy application modernization has several uses, with two of the most common being cloud adoption and/or cloud migration and improving automation. 

IBM cloud modernization and migration allow legacy application systems within an organization to be exposed or moved to a cloud infrastructure that runs on cloud functionality. No data or business processes/logic must be lost during the integration or transfer, as this may impair the function of the system. With cloud popularity growing, this is a widespread use case for IBM cloud modernization for apps. 

The technique is often used to improve automation functionality too. Automation is highly useful in business systems for testing and continual monitoring, but certain legacy systems are not compatible with it. However, IBM mainframe modernization can be used to facilitate automation within a system.


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