CICS COBOL to .NET Conversion

Typically the reasons for conversion are:

 

Cost – The cost to maintain and support a legacy platform is not competitive with newer platform and technologies available

 

Resources – The availability of resources to maintain and support legacy applications is non-existent/very limited or too costly

 

Agility – Legacy platforms typically do not have the sophisticated tools available, hence it takes longer to implement a change.

 

There are essentially two broad conversion approaches:

 

1- Migrate

Keep the same code base and design, but move to a new platform by using helper libraries and platform architected to map the original architecture

 

2- Re-Model

Re-architect the system into a new platform entails re-design of the application. The design and architecture is standard for the target platform

 

Migrate
- CICS COBOL to .NET Migration

• The migration process covers:

• Code
• Database
• Data Platform

 

Pros
- CICS COBOL to .NET Migration

• Exact Replication
• Maintainable by original developers
• Quick baseline
• Reduced risk
• Error handling & security
• Testing
• Some degree of automation possible
• Lower degree of end user involvement

 

Cons
- CICS COBOL to .NET Migration

• Exact Replication
• Error handling & security
• Testing
• CICS Application Server
• COBOL .Net
• JCL Migration
• Maintainability (resulting code looks like original)
• Client server -> web based
• Not fully automated

 

Suited when:
- CICS COBOL to .NET Migration

• Target platform is similar to original
• Maintenance & Testing staff is on hand
• Well documented

 

Approach
- CICS COBOL to .NET Migration

• Planning – Prepare project plan
• Data Model – Model equivalent data structure in the new platform
• Pilot – Do a pilot conversion of the code and migration of data
• Test & Tune – Review results of the pilot and fine tune
• Migrate – Carry out mass migration of the application
• UAT
• Deploy

 

Migrate - Planning
- CICS COBOL to .NET Migration

During the planning phase:

• Inventorize – Develop a complete inventory of the source code of the application version that is running in production, (Natural programs, maps, data areas, etc.)
• Clean compile – Clean compile the source code and compare to the version in production. This step is to ensure that the inventory is complete.
• Exceptions – If during the previous 2 steps any issues were found address them to ensure that all source codes exist and are the correct version.
• Cross reference – Develop a comprehensive cross reference (program to program/maps, program to file, etc.)
• Data definition – Develop a detailed data definition including all multi-value fields, group fields, etc.
• Batch processes – Develop a detailed list of batch processes, and JCLs targeted for conversion
• External interfaces – Develop a detailed list of external interfaces and trigger points
• Change management – Develop a planned strategy for change management for during migration and code freeze
• Project Plan – Based on the above a detailed plan is developed to track and monitor the project

 

Migrate – Data Model
- CICS COBOL to .NET Migration

Data Modeling involves:

• The primary objective of the data modeling is to develop an equivalent data model that closely resembles the original application in the target platform.
• Multi-values fields needs to be flattened out
• Group fields need to be mapped to multiple tables
• Multiple record formats need to be mapped to multiple tables
• Naming conventions for tables and columns
• Data type changes

 

Migrate – Pilot
- CICS COBOL to .NET Migration

The pilot phase involves the following:

• The purpose of the pilot conversion is to establish a baseline for the conversion and test and tune that baseline
• All key decisions are made during the baseline conversion and the baseline determines how the resulting application will look like and perform
• The pilot must include the migration of the code as well as the data
• Code Migration

• CICS conversations converted to TXSeries/NeoKicks equivalent
• CICS maps are converted to ASP screens
• COBOL programs are converted to COBOL.Net
• VSAM calls are replaced with SQLs
• JCL conversion to batch files
• Substantial session state usage

• Data Migration

• Develop data mapping
• Develop ETL programs

 

Migrate – Test Pilot
- CICS COBOL to .NET Migration

Different types of testing needs to be carried out on the migrated application:

• Test Plan – The test planning is a critical part of the overall testing. Development of a test plan early on in the project will help organize for this activity, as the migration can happen quickly and the users need to be ready for this.
• VSI QA – VSI will carry out some testing at their facilities before the application is shipped out, but this testing is limited to white box as detailed application domain knowledge would not be available.
• UAT – This is the critical testing to be carried out by the users to verify the correctness and accuracy of the converted application, and accept the converted application. Some of the test cases may need to be modified to match the new version of the application.
• Stress Test – Once the application has past UAT, stress testing needs to be carried out to fine tune its performance.

 

Migrate – Migrate/UAT/Deploy
- CICS COBOL to .NET Migration

This is the last step of the project:

• Migrate – Conversion of the complete application is carried out, based on the strategy developed. At this time a code freeze needs to be put into effect till the converted application is taken into production
• UAT – User testing of the migrated application and acceptance of the converted application
• Deploy – Finally the converted application is deployed in the target environment

 

Re-Model
- CICS COBOL to .NET Migration

The Re-Model process covers:

• Application functionality
• Database Design
• Data Migration

 

Pros:
- CICS COBOL to .NET Migration

• Technical and functional uplift
• Can be maintained by anyone in the new platform
• Error handling & security
• Testing
• .Net Application Server
• C#/VB.Net
• Maintainability
• True web based (MVC, SOA)
• Change management and code freeze is not needed

 

Cons:
- CICS COBOL to .NET Migration

• Not an replication it is a new app
• Upfront heavy requirements and design phases
• Higher risk
• Error handling & security
• Testing
• Not automated
• Higher degree of end user involvement

 

Suited when:
- CICS COBOL to .NET Migration

• Target platform is different to original
• Maintenance & Testing staff are not available or have limited knowledge of the code
• Poorly documented or documentation not up to date

 

Approach:
- CICS COBOL to .NET Migration

• Requirements Engineering – The application functional requirements are documented
• Re-design – The application is designed in the new platform
• Data Model – Model the database in the new platform
• Develop – The application functionality is coded in the new platform
• Data Migration – Existing data from the legacy database is migrated into the new data model
• UAT
• Deploy

 

Requirements
- CICS COBOL to .NET Migration

Gather functionality of the existing application and business requirements. This will involve VSI BAs working with IT and business teams, as well as study of the existing application. At this time functional uplift, such as new and enhanced features can be considered.

 

Design
- CICS COBOL to .NET Migration

The design of the application can now take place irrespective of the original design and architecture and modern design elements can now be introduced such as relational data model, MVC, SOA enablement etc.

 

Develop
- CICS COBOL to .NET Migration

Once the design has been developed and approved, the application is developed. The development for large size application typically takes place in phases, along with testing and deployment.

 

Test & Tune
- CICS COBOL to .NET Migration

Once developed the new application is first tested by the end users for acceptability and then fine tuned for performance.

 

Data Migration
- CICS COBOL to .NET Migration

Data mappings and ETL programs are developed to migrate the data from the source to the target. A test run of the data migration is first carried out before the final migration into the new platform at the time of deployment.

 

Deployment
- CICS COBOL to .NET Migration

Finally the new applicationis deployed in the new environment.

 

Visionet’s Reengineering Methodology Technical Uplift
- CICS COBOL to .NET Migration

• Abstraction of data and UI into generic model
• Replacement of UI elements in the business layer by the model above
• Removal of direct DML operations from the business layer
• Identifications of patterns in the business layer
• Refactoring of business layer to new design
• Conversion of required business components in to compliant SOA modules
• Removal of Business layer calls from UI
• Binding UI elements with the generic UI model
• Improving the user experience through custom developed rich UI controls
• Maintaining the desktop hangover by employing client side caching and AJAX call

 

 

 

back to CICS COBOL to .NET Migration