Abstract
Today, many enterprises are looking to modernize their IT landscape – including their AS400 systems (that run mission-critical legacy applications that are difficult to maintain and expensive to operate) – to gain higher scalability, agility and cost benefit.
This white paper analyzes the challenges of modernizing AS400 systems along with various modernization approaches and useful architecture patterns that maximize the benefit of AS400 modernization. This will be useful to an IT decision-maker in any organization looking to modernize their existing AS400 system.
Introduction
IBM AS400 (also known as ‘IBMi’ or ‘IBM iSeries’) is an application server with proven robustness, scalability, reliability, security and low cost of ownership compared to MIPS in IBM Mainframe (also known as ‘IBM z’). The advent of newer technologies forces an increased need to modernize AS400 systems to harness greater value.
Every company that uses AS400 systems wants to leverage and reap the benefit of the large volume of valuable information stored in it. However, limitations such as the monolithic nature of the code base, 5250-based ‘Green Screens’, tightly coupled Business Logic along with high cost of Server/OS upgrades, create greater challenges to the modernization of AS400 systems.
In the case of the AS400 system, unlike IBM Mainframe systems, IBM does not charge customers based on the number of transactions (MIPS – Million Instructions per Second), but it’s a sunk cost instead. In other words, the AS400 system is not an expensive server to maintain and hence the modernization should deliver benefits beyond reducing cost. AS400 systems need a customized approach that reduce Total Cost of Ownership (TCO), unlock insights from hidden data and increase system agility while delivering consistent business value.
Given the large AS400 footprint on the IT landscape and the variety of technologies, databases and supporting software involved, a one-size-fits-all solution for AS400 modernization is unlikely to succeed.
Modernization challenges
AS400 system modernization is complex and requires different approaches depending on the requirements, workload and risk profiles.
Common causes for delay in AS400 Modernization Projects are:
Modernization approaches
Re-hosting does not require any change to the existing interfaces or functionality and can run the existing AS400 applications on an x86-64 cloud-based instance using an AS400 emulator such as Infinite i – a suite of compilers, utilities and operating system services that allow applications programs (developed under RPG or COBOL for the AS/400 environment and database) to be migrated at the source code level, recompiled and executed on AWS including the complete replication of database DB2/400. Application components that use third-party tools such as Message Queues, Schedulers, Printing, Reporting, Backup and Tape Management are also migrated to the cloud environment. This allows the applications to execute as they did on their original platform without having to rewrite large portions of the code. Wipro works with multiple re-hosting and enterprise software partners to deploy and manage their software on the cloud environment.
Batch Jobs such as ETL data processing, EDI file processing and Ad-hoc report generation form a significant portion of AS400 applications that are business critical, however, mostly have low business value, resulting in lower agility and high cost and becomes a good candidate for migration to the following two distributed solutions on the cloud:
If the current AS400 application is no longer able to meet future-state business requirements (or) an agile, target architecture (or) does not qualify for a re-hosting solution, then the Re-Architecture approach is considered for similar or enhanced functionality and performance.
The above picture depicts Re-Architecting approach to cloud-native applications that involves four key elements:
Microservices:
Applications can run code without provisioning or managing the server while paying for the computing time only. This can be achieved by using a cloud-based API Gateway and server-less applications like AWS Lambda/Azure Functions. These discrete functions form the core of the Re-Architected application and allow wrappers to connect to the on-premises AS400 when needed. An application built using the server-less architecture follows an event-driven approach. An in-memory caching layer ensures faster response time for both read and write access to data, thereby solving data challenges that emerge within the microservices architecture.
Application, containers & queues:
Docker containers (the cloud container service) and message queues enable the workflows and other application-related services to decouple complex business functionalities and then can be deployed and managed at scale using open source and cloud native services.
Data persistence & data lake:
Persisting data in the cloud to services such as managed relational databased, NoSQL database, data warehouses, and cloud storages enable customers to effectively store and analyze data in ways that were previously not possible.
Data analytics, artificial intelligence & machine language:
Once data is persisted in the cloud, customers can leverage cloud-based Hadoop and Wipro HOLMES to get different insights from data. Wipro HOLMES is a machine learning and artificial intelligence powered platform that offers cognitive services that accelerate business processes through automation.
Rajaraman Mahadevan
Delivery Head for Application Modernization, Wipro limited.
He brings in 25 years of IT experience with core strength in analytical skills, extensive business knowledge of enterprise wide applications and experience in designing applications. He has led successful IT Delivery organizations serving global leaders in Banking & Retail industries.
