The Business Value of Legacy Migration

Reducing Costs and Improving Agility Through Legacy Migration

06 Dec, 2010

Summary

Legacy applications are usually the most valuable software systems many large organisations possess. During the twenty, thirty or more years they have been used much effort has gone into making sure they deliver value, integrate with other applications and implement the methods and style of the organisation. The term ‘legacy’ does not usually refer to the functionality these applications deliver, but indicates aging software and hardware infrastructure that is expensive to maintain and inhibits change. Separating the inherent value of an application from its restrictive infrastructure is the main task associated with legacy migration. Moving an application to a contemporary hardware and software infrastructure has many benefits associated with it:

• A migrated system is more amenable to change, enhancing the agility of the
  organisation.
• Software licensing costs are dramatically reduced.
• Hardware infrastructure costs are reduced.
• Integration with other systems becomes less costly and easier.
• Application runtime performance is enhanced - which can deliver large productivity
  gains.
• Access to more productive development tools.
• Access to a larger skills pool.

Having decided that a legacy application is too costly and inflexible, management have
several options available to them - legacy migration being just one of them. All options have their
associated benefits, costs and risks, but in many instances migration will be the lowest risk, and
lowest cost option. The main options are:

• Total rewrite on a new hardware and software platform. This is probably the highest risk option in many cases. Not only is a large design and programming
  effort involved, which by its nature will introduce many teething problems, but the
  organisation is presented with a new set of unfamiliar technologies which have to be
  understood at the same time development is taking place - effectively doubling the
  uncertainty. Rewrites are not short projects; the organisation can expect a project
  of this nature to take at least three years and often longer. Meantime the existing
  systems have to be maintained and modified as the business changes. These changes
  have to be replicated in the new systems and developers often find themselves
  aiming at a moving target.

• Buying a solution can also be an option for some applications.
  In some ways this is riskier than the rewrite option. While the technical risks are lower the operational
  risks are higher. The organisation is presented with a wholly new way of working,
  and not until all the pieces are in place and the application is used will management Reducing Costs and Improving Agility Through Legacy Migration know whether the packaged solution provides a suitable option. Operational
  disruption is always experienced when wholly new applications are implemented
  and sometimes this can become chronic. There are many well documented examples
  of packed applications bringing an organization to its knees - and in rare cases
  causing it to fail.

• Legacy migration is much speedier than a rewrite (possibly by a factor of three or
  four) and the operational risks are low - simply because the functionality is already
  familiar. It will almost certainly be the lowest cost option and depending on the new
  software and hardware platform, may provide the lowest ongoing operational costs.
  If managers are unhappy with the functionality a legacy application provides then
  legacy migration is probably less appealing.

The technologies to achieve legacy migration have moved on considerably during the last
decade. Much of the process is automated and sophisticated workflow systems help the migration
team deliver the resulting application much more rapidly and with fewer teething troubles. We
expect this development in migration technologies to continue as the need for legacy migration
increases.It is our opinion that legacy migration is a low risk, speedy route to move applications
from aging infrastructure that should be preferred to more radical solutions in many instances.

To view this document in its entirety, please download The Business Value of Legacy Migration PDF