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What is a Legacy System?

Need to review a legacy system for an information management strategic plan and want some practical timesaving suggestions?

Legacy system is a term we apply to older computer systems andLegacy System applications. They may have been developed in the late 1960’s and 1970’s but the term also applies to some systems that were developed much later than that.

These systems have usually been in production for a long time. They are typically found in organizations such as financial institutions and large government departments
and continue to meet original requirements.

Why is a legacy system review important?

Information management is all about getting the right information, in the right hands, at the right time, to make the right decision. The trend today is to get a consolidated look at information to help manage things like customer relationships.

Older systems are frequently called “silo’s”—They don’t talk to each other easily. That means we need new information management systems to extract data from several source applications, integrate it for storage and reporting purposes, and present it for business intelligence use.

We need to look at existing systems and technology to fully understand the complexity of information management. In other words, we need to get an idea of how much data integration work will be required to manage information stored in these “silo’s”.

Why don’t we just replace all the old systems?

That’s a good idea and some organizations have made significant investments to upgrade or replace older systems.

Owners are generally reluctant to replace or re-write these for a variety of reasons including:
  • Prohibitive cost;
  • Re-training;
  • No real cost/benefit; and
  • The system is “mission-critical” and the business cannot operate without them.
Can you imagine an airline operating without a reservation system? How long would they stay in business?

How about a bank? Think of the increase in customer service calls if on-line banking were interrupted for even a brief period.

The systems may be old, and require a lot of maintenance, but they still work and meet requirements—So replacement involves too much risk for now.

In my opinion
Many of these systems will be replaced as we find it more difficult to keep them running with hardware and software that is starting to become “dated” or even “obsolete”


What is important for an information management strategic plan?

I generally like to gather the following information:
  • The system name;
  • IT owner;
  • Business owner;
  • A brief description of what the system does;
  • An understanding of metadata components, which means I look at "is meta data available and current"
  • What is the perceived data quality?
  • What is the cost of maintaining the system?
  • What are the skill levels of the production support staff?
Finally, to complete the information management strategy documentation, we need to map the entities from the entity relationship diagram to each existing system. For each entity, ask if the system:
  • Creates the entity?
  • Reads it?
  • Updates it; or
  • Deletes it?
Summary...

Legacy systems will be here for a long time and we need to understand them so we can assess the complexity of extracting data for business intelligence purposes.

The more information we can gather at the strategy stage means the less work we need to complete later.