It’s not easy to maintain legacy systems, let alone improve them. The biggest legacy technology challenge for many organizations? The mainframe.

Often incredibly complex due to significant amounts of historical development and, as they’re built using aging technology, a lack of access to knowledge and skills tends to be the biggest obstacle to modernization. These issues are part of the reason as to why so many are fearful of modernization programmes.

Mainframes have certainly served a valuable purpose over time, and they continue to do so as they remain business critical. However, these monoliths are holding organizations back due to their inflexibility – severely affecting business agility and a firm’s ability to adapt to market conditions and meet customer expectations. This will continue to be the case until an organization modernizes their legacy systems and embraces modern technologies, which serve as a key enabler to greater agility, speed to market and time to value for new applications and features.

Why it's so hard to tackle the mainframe?
It’s well known that it’s tough to transform mainframe applications. Complex interdependencies between applications, spider webs and spaghetti connections create a huge fear that breaking one application may cause a domino effect across a whole range of others. That’s a rational fear when you consider how critical these applications are to an organization’s ability to operate.

We’ve mentioned the lack of applicable skills already, and it’s critical to recognize that the number of people with these heritage skills is shrinking, as these technologies and languages (such as PL/I, IMS etc.) are no longer taught.

The usual approach
Due to this fear and complexity, most organizations take a simplified migration approach – where every part of the mainframe goes through a basic “lift and shift”. This rehosting effort can be a good starting point, but many make the mistake of thinking this is the final destination. On a positive note, from rehosting, you will at least benefit from cost savings as the applications will cost less to run in the cloud.

However, this one size fits all approach represents a significant missed opportunity as you will not gain any modern architecture advantages. The legacy constraints and limitations will be carried into and remain in the rehosted solution, and you still won’t be able to evolve the applications any better than you could when they were on-premise.

In this scenario, the majority of the legacy problems have just been "lifted and shifted" to another platform or solution. The legacy code will still exist (albeit in a different place) and the legacy interdependency and integration issues will still be there. Then there’s the opportunity cost to consider, what opportunities might your organization miss out on by failing to modernize?

If reduced cost is your only goal this lift and shift approach is an acceptable solution, but if you’re looking for business value, you'll need to face your mainframe fears and expand further.

A strategic, incremental approach
Business value comes from a strategic, measured approach, and as you might expect, it’s more complicated, but more rewarding.

It’s important to accept that a gradual modernization of your mainframe estate is ok – in fact, it will deliver significantly greater benefits to your business than a one-size-fits-all migration. You’ll also quickly start seeing how modern architecture can enable your business strategy as you modernize your mainframe estate.

Follow these 4 steps to identify how you should be tackling your mainframe:

1. Inventory everything – not just the mainframe apps, but everything that has a dependency on mainframe
2. Assess business importance and future functional fit – bring the business to the table for this step
3. Identify those applications that require regular change, then rank them based on business importance and change requirements to create a priority list
4. Select the most suitable “R” modernization strategy for each priority application first

By identifying the applications that are the most business critical, and those that require frequent change you can prioritize your efforts based on business value and impact.

7 Rs of application modernization
Avanade classifies application modernization strategies as 7 Rs:

Most of your priority applications will require a Refactor, Reimagine or Replace approach, as this will enable change and enhancement that delivers on business needs and creates new business value. It’s also important to be aware that some of your most complex applications may require a combined approach – for example you may Replace core functionality with commercial off the shelf (COTS) software and then Refactor or Reimagine any missing functionality and back-end components in order to protect and maintain business logic.

Making the right modernization choice
In order to select the right modernization approach for each application, you’ll need to go through a holistic decision-making process to assess application characteristics, security and regulatory requirements, migration complexity, interdependencies, cloud technology availability and more.

Read our guide to mainframe modernization to learn how to structure and shape your modernization programme, and for further details on the modernization decision making process.