Lot’s of companies, from small firms to large enterpises are running old software; sometimes very old.
When such software itself usually working fine and does its job, maintaince of it quite often is expensive and required resources and efforts the companies want to minimize or avoid completely.
POS software, ATM front-end and back-end, industrial application etc are just tine part of possible examples of widely-used old software.
The essential part of virtually all applications is some type of database engine. When user interface, network-related routinies, hardware — servers, working stations — are easily upgrading from time to time, the database structure is the most stable and constant part of the application design.
The problem is that maintaining outdated or some kind of unique database engines required hiring qualified software engeneers with all the consequences. Sometimes database engine support is not available anymore. Sometimes the support is excessively expensive.
Our client, a large health insurance company (they didn’t allow us to disclose their name), wanted to complete unification of databases and asked us to migrate their DBs and corresponding business application to MS SQL. These were Sybase Adaptive Server, Informix, old Oracle’s and DB/2.