Things to Consider Before You Migrate Your AS400

Aug 23, 2021 Rima Dutta
Back in the 80s, introduction of AS400 was one of the most powerful waves that hit the IT industry. An integrated combination of hardware and software, with an embedded database & its operating system, this constitution by IBM had revolutionized an array of businesses and how they dealt with their data.

30 years, that’s quite a leap and yet we have a number of organizations that entrust the AS400. But with the shrinking resource pool and customization debris accumulated over the past ‘n’ number of years, there’s been an evident trend of emigrating out of the IMB setup.

AS400 is a classic but let’s face it, it gets expensive to run mission-critical tasks on this vintage IT beast, the reason why a fraction of its users is actively considering the option to migrate off of the system. While a well-thought-out migration can enhance flexibility, accessibility, and security by leaps & bounds, a hasty one can make things go haywire in the blink of an eye. AS400 migration is cumbersome, takes a significant period to yield results, and demands major diversion of finances. When stakes are this high and investments are gigantic, it’s better to take calculated steps, preferably with an expert opinion.

In this blog, we discuss about the pre-requisites that organizations must take care of before migrating from AS400 to newer, modern applications.

10 Pre-requisites to a Successful AS400 Migration

Our team of experts at Nalashaa has curated a list of top ten areas you need to consider to ensure that your AS400 migration is a hit.

  1. Application Knowledge – This might sound cliché, but knowing the AS400 inside out is the first and foremost criterion that needs to be fulfilled before anything else. This setup is constituted by many components, including the hardware, software as well as the operating system, therefore, comprehensive knowledge of system programs, interfaces and every little aspect that’s related to the AS400 application will be a parameter to decide how well versed the teams are.
  2. Business Analysis – What good is a migration if it proves detrimental to the financial outcome, right? We recommend an in-depth pre and post ROI analysis by the business team, which should talk about the business aspect of AS400 migration, its comparative study, probable trends of revenue in the near future along with possible measures for improvisations.
  3. Data Quality Checks – Data quality check is a scrutiny multilayer that involves performing quality checks, data clean-up, elimination of replicated data, etc., all with an objective to ship only clean data to the new system. This step facilitates the migration to be seamless by ensuring the optimal health of data.
  4. Integrations – Before decommissioning the AS400, taking care of the already integrated third-party interfaces is primal. With a new setup in place, organizations need to chalk out a way to evaluate and plan as to how they would incorporate this in the new system. Mismanagement of the current AS400 integrations might lead to severe clogging in the workflow.
  5. Encryption of sensitive data – Data is crucial for any type of legacy migration. Encryption of sensitive information is important to ensure secure access to data, the storage, and its retrieval process. AS400 migration is a dynamic conjuncture, therefore, encryption of the information on disk as well as cloud is primary.
  6. System Documentation – We cannot stress enough about the importance of AS400 System Documentation. System documentation wasn’t a part of the original SDLC, which is why a detailed record consisting of all the system components, policies & procedures, system architecture, data model diagrams, network configuration, etc. plays a crucial role during migration.
  7. User Compatibility – Before sun-setting the AS400 that has been with the organization for the past ‘n’ number of years and getting started with something entirely alien to its user base, it is recommended to take into consideration the user compatibility percentage and opt for a solution that resonates with the same.
  8. Risk Assessment - This involves awareness and counter moves to seal the security leaks present in the current system. In a process like AS400 system re-write, the effects of such vulnerabilities are exponentially larger. A team of IT minds who are well versed with the system should look out for any weak link in the architecture before proceeding with the migration.
  9. Build Vs Buy – Market analysis of whether to buy a third-party solution or build a customized set of modules specifically designed for your needs helps reduce the cost incurred, time invested, and channelized efforts exponentially. An analytical consultation weighing the pros & cons of both routes helps organizations make informed, fact-based decisions.
  10. Backup - Even though you’re all set to get started with the new front, it is still advised to keep the previous AS400 up and running for a pre-defined time period after the migration. An otherwise seemingly redundant measure, it acts as a confirmatory test for the credibility of the new system. Furthermore, if things turn south, enterprises will always have a cushion to fall back to.

One Step at a Time. Here’s why

The decision of whether to migrate or not sends shivers down the spines of many seasoned business & IT professionals. Anyone who’s been there, done that, can testify the magnitude of anxiety felt when the day comes to switch from your AS400 to the new application.

What if something surfaces that we didn’t anticipate? How long will the business be down? What if something goes wrong? Did we miss something? Should we consider a buffer plan?

These are a few from the lot. While you certainly cannot put a check on the interrogative bubbles popping in your head, you can hold up an optimistic answer to each. How?

Simple! By taking care of all the above-mentioned pre-requisites. Here’s a curated list of advantages that you get out of it.

  • Certainty
  • Eliminate ad hoc
  • Low Resolution Time
  • Buffered Processes
  • Simplified Execution
  • Planned Transition

The “IDEAL” Plan

Once the mandates and the migration options are finalized, this is what the “ideal” plan should look like:

Step Tasks
1. Initiation Define & prioritize objectives
2. Assessment Technical and functional evaluation
3. Strategize Migration blueprint, setup & training plans
4. Migrate Re-write the AS400 with complete testing
5. Maintain L2/L3 support with system maintenance

Don’t be afraid to ask for help

AS400 migration is a tedious and complex endeavour which is why it’s recommended to have a second opinion to get you through the lows of the process. Our team of AS400 experts have been in the industry for over a decade now and we understand the complexities that it comes with. We help you get started and stay relevant in this journey.

Reach out to us at and we’ll get back to you at the earliest.

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Rima Dutta

Made my favourite sandwich using the best of both worlds - Technology & Writing. The girl next door who talks to the camera, cries watching K-dramas and has an unhealthy obsession with momos & fictional characters.