Many organizations maintain large legacy applications which are both mission critical
and increasingly difficult to maintain. Typical challenges associated with the support
of legacy applications include:
- The lack of application documentation
- Limited knowledge transfer between development staff
- Non-standard database – limited system integration options
- System instability – application ‘bugs’ persist and are difficult to resolve
- Lack of confidence in application data – reconciliation errors, report second guessing
Modular development, n-tier architecture and web services have rendered many legacy
applications obsolete. Many haven’t considered re-engineering their applications
for fear that the costs and business interruptions will be too much for the organization
to handle. A disciplined legacy application re-engineering approach mitigates many
of the risks associated. MethodFactory employs its client proven, low-risk development
methodology (MDM) for all re-engineering engagements.
- Application Orientation: This phase
includes application architecture knowledge transfer and business process documentation.
- Application Re-Design: This phase
mirrors the Planning phase in the MethodFactory Development Method. A system design
document is developed after a detailed review of current application functionality
and the conclusion of functional workshops.
- Application Development: The new
application is developed while the legacy application is maintained. A control version
of the legacy application is used as a baseline for new application testing. In
some cases modular development allows elements of the new application to be introduced
into legacy application.
-
Legacy Application Retirement: This
phase includes new application testing & deployment, legacy application data
migration, parallel production system use and final system cutover.