Mainframe applications are composed of extensive code bases, comprising millions of lines of code, with interdependent programs forming monolithic structures.

Development adhered to the Don’t Repeat Yourself (DRY) principle to minimize code redundancy. A similar pattern for data access is observed, where multiple applications access the same table without clear data ownership, which undermines deployment independence.

Applications are tightly integrated using transaction manager proprietary interfaces, resulting in strong coupling. They exhibit dependencies on specific platforms or middleware, with static parameters including credentials, Application Identifier (APPID), and IP addresses hardcoded, which limit flexibility. Proprietary APIs and tight integration further constrain applications, impeding adaptability to architectural changes.

Mainframe applications use proprietary gateways and outdated interfaces such as SNA, and 3270, resulting in non-standard integration with modern distributed systems. This implies changing code, configuration, and installing additional software for REST API enablement.

Mainframe applications use proprietary programming languages such as COBOL, PL/I, ASM, DL/I, REXX, JCL, CLIST, and proprietary file formats (VSAM, PS) datasets. Programs are compiled and delivered through non-standard or internal processes. Installation software has unique installation processes and requires specialized skills such as System Modification Program/Extended (SMP/E) skills.

Application code can remain untouched for years or even decades for various reasons. It consistently delivers the business value as expected, relies on backwards compatibility with existing systems, with often no comprehensive modernization plan.

It is common to encounter mainframe development practices which have seen limited architectural and code changes since the creation of the application. In addition, the applications rely on proprietary utilities with thousands of parameters that are complex and require strong expertise for effective utilization.

These aging code, practices, and complexity make it challenging to manage and maintain mainframe applications, and can make it difficult to find qualified personnel.

3270 Interactive System Productivity Facility (ISPF) is a software product used in mainframe development environments. The interface is less intuitive than new agile mainframe development tools.

Customers need cross-platform integration and unified development experiences to accelerate application modernization, and development team productivity.

Automation on the mainframe is achieved by using a set of scripts and batch JCL. It is used for application lifecycle tasks such as Initial Program Load (IPL), application restart, facilitating high availability and disaster recovery. Although automation is used around mainframe applications, there is not a unified and standard approach to deliver Infrastructure as Code for mainframes lacking templates describing mainframe subsystem infrastructure resources and configurations.

One example is the creation of on-demand testing environments. Testing on the mainframe is often manual and organizations have integrated internal and ad-hoc testing solutions, making it difficult to automate the creation of on-demand and elastic testing environments.

Mainframe application development, testing, and deployment teams operate in silos. This segregation hinders effective communication, knowledge sharing, and collaboration throughout the application lifecycle. The lack of coordination leads to inefficiencies and delays.

While there have been efforts to improve the mainframe development speed or improve the DevOps toolchain integration, modern tools are not widely adopted. They are continuously challenged by the mainframe integration and legacy processes that are blockers for collaboration.

Many mainframe systems are outsourced, with infrastructure and application maintenance handled by third-party vendors, managed service providers, or global system integrators.

Teams operating the mainframe environments are often siloed (databases, storage, operations, security, and performance) with no overall ownership.

This results in limited visibility into spending, observability, and end-to-end system control.

An application refactored with AWS Blu Insights Transformation Center results into agile services such as macroservices or microservices. The workload is decomposed into business domains and also decoupled into a 3-tier architecture (user interface, application, and data layers).

A replatformed application with Micro Focus and NTT DATA is decoupled into a 2-tier architecture (user interface/application, and data layers).

Modernized refactor or replatform workloads are independently deployed in a multi-tier architecture across elastic compute and database services in multiple AWS Availability Zones, and Regions. It removes affinities between components and improves resiliency with a focus on overall application availability.

By modernizing mainframe applications with the refactor pattern, organizations modernize mainframe programming languages, and benefit from popular technologies with a larger skills pool. AWS Blu Age Refactor creates via an automated process modern applications from mainframe source code. Applications in COBOL, PL/1 or NATURAL are transformed into modern distributed applications relying on Angular and Java/Spring. Standard interfaces such as REST/JSON APIs are created during the automated refactoring to Java.

By modernizing mainframe data structures (Db2 for z/OS, VSAM, IMS, IDMS), organizations adopt modern relational database and standard file systems.

Once modernized with AWS, the application stack benefits from AWS cloud-native fully managed services. It removes the heavy-lifting of configuring and managing infrastructure resources.

For example, refactored applications run on AWS Mainframe Modernization fully-managed runtime environments. Modernized relational database runs on PostgreSQL or other managed databases such as Amazon Aurora, Amazon RDS for PostgreSQL, Oracle database, IBM Db2. File systems run on managed Amazon Elastic File System or Amazon FSx.

For applications modernized with AWS Mainframe Modernization toolchains (AWS Blu Age, Micro Focus, NTT DATA), Integrated Development Environments (IDEs) are available for code development including smart editing, local build, unit testing, and debugging features.

AWS CLI, SDK, and CDK play complementary roles in the development lifecycle providing the developer tools to build, deploy, and manage applications on the AWS Cloud efficiently.

The IDEs toolkit has been strengthened with a generative AI–powered conversational assistant (Amazon Q), an AI Powered productivity tool (Amazon CodeWhisperer). Developers receive code suggestions or ask questions about building software directly from the IDE.

Serverless and cloud-native fully-managed services provide higher-level simplified APIs so that administrators don’t have to deal with the undifferentiated heavy lifting. These higher-level services and APIs are called and orchestrated using infrastructure-as-code, templates, and cloud development kits. It enables developers to focus more on building and improving applications rather than managing infrastructure manually.

Infrastructure-as-code allows managing, provisioning, and operating infrastructure components using definitions, templates, or code. Infrastructure-as-code provides automation, consistency, and traceability. It also avoids configuration drift. It’s a fundamental building block for supporting DevOps and SysOps pipelines and operations at scale.

AWS CloudFormation provides a powerful and scalable way to manage and provision AWS infrastructure. With AWS CloudFormation, you use a declarative syntax in simple text files called templates. These templates model all the infrastructure resources and configuration you need. Similar to application code, infrastructure as code is maintainable and versioned in repositories.

The surrounding services and processes introducing DevOps and SysOps at scale are also modernized with Infrastructure as Code. This is facilitated with the large choice of fully managed services for continuous integration, testing, and continuous deployment such as AWS CodePipeline.

Discoveries for both automated refactor (AWS Blu Insights) and replatform (Micro Focus Enterprise Analyzer) generate applications analysis, complexity and interdependencies reports. It gives more confidence to technical leaders and developers, to make faster changes.

Transformed and refactored applications to Java is documented with a generated Javadoc for technical documentation.

By modernizing processes with DevOps, SysOps, and enforced by a Cloud Center of Excellence, teams remove silos and increase processes observability for better knowledge sharing. This improves collaboration on projects to deliver on time, meeting organizations standards.

Modernizing mainframe data onto AWS and leveraging cloud-native services create new opportunities to unleash collaboration with data analytics, and AI teams to address new business requirements.

AWS Mainframe Modernization managed service removes the burden of managing mainframe infrastructure and enables organizations to focus on innovating and building new capabilities.

Customers have control over their AWS infrastructure with a range of services fostering observability with Amazon CloudWatch, and Security, Identity, and Compliance services.

Pay-as-you-go elastic pricing and no upfront or termination fee facilitate a low cost of entry and faster experiments for migration and innovation. In addition, you can select committed plans for additional savings.

AWS Cost Management tools provide visibility into spending and forecasting across business lines.

AWS Billing offers features to track, measure, review, and forecast the carbon emissions generated from your AWS usage using the AWS Customer Carbon Footprint Tool.

Opportunities to rearchitect any migrated workloads according to organization’s sustainability objectives may be considered. AWS provides guidance thanks to AWS Well-Architected Framework – Sustainability pillar.