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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 and
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.
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