LLM-Driven COBOL Monolith Refactoring
Key Points
- Maintaining a massive, monolithic COBOL application with thousands of files and a large database is cumbersome and makes pinpointing needed fixes difficult.
- Large language models that understand COBOL can automatically generate documentation, making the codebase far more navigable.
- Using an LLM‑powered Refactoring Assistant, portions of the monolith (e.g., customer‑related logic) can be extracted into independent services while preserving the original functionality.
- This service‑oriented approach simplifies maintenance, enables API exposure for broader company integration, and turns the developer into a strategic “hero” by streamlining daily work and delivering business value.
Full Transcript
# LLM-Driven COBOL Monolith Refactoring **Source:** [https://www.youtube.com/watch?v=_6xJ4oQ9t9c](https://www.youtube.com/watch?v=_6xJ4oQ9t9c) **Duration:** 00:03:05 ## Summary - Maintaining a massive, monolithic COBOL application with thousands of files and a large database is cumbersome and makes pinpointing needed fixes difficult. - Large language models that understand COBOL can automatically generate documentation, making the codebase far more navigable. - Using an LLM‑powered Refactoring Assistant, portions of the monolith (e.g., customer‑related logic) can be extracted into independent services while preserving the original functionality. - This service‑oriented approach simplifies maintenance, enables API exposure for broader company integration, and turns the developer into a strategic “hero” by streamlining daily work and delivering business value. ## Sections - [00:00:00](https://www.youtube.com/watch?v=_6xJ4oQ9t9c&t=0s) **LLM‑Driven COBOL Monolith Refactoring** - The speaker explains how large language models can auto‑document a sprawling COBOL codebase and then assist in extracting functional components into independent services, dramatically simplifying maintenance of a legacy monolithic application. ## Full Transcript
So you're a COBOL developer, and you're having to deal with this monolithic application
with thousands of files that you have to maintain,
you have to provide this business function,
and it's absolutely critical to the business.
So here we have this app, all these files, hard to manage, hard to maintain, hard to understand which pieces do what,
and it's connected to this really large database with all of the data related to that application, say insurance or finance,
but this is a monolith that you've been working in and it makes your life hard every day
trying to understand where to fix that problem that we need to address.
Thanks to large language models, we have new capabilities.
So using a large language model that understands that COBOL,
what you can do is take this application and you can add documentation to it.
So you can have the language model understand it and dock it,
and now it's easier to understand, but it's even better than that.
What you can do is take this app with this documentation now included in it,
and you can use Refactoring Assistant to move it into a service.
So right now this app does all sorts of things, but you can take that and pull parts of the code out.
It's the same code.
but you're pulling it out and you're redesigning to create this service.
Maybe it's, let's say, customer.
So everything related to customer, the customer data, customer application pieces pulled out, and here they are.
Now, this is easier to maintain and manage.
And while you're working, this monolith can call the customer app when it needs to.
And over time, you can build.
all of the services that are necessary to work with this application, all segmented.
So you go from this monolith to the individual services.
This makes it a lot easier to manage, maintain, get your job done, and understand the pieces of the application.
This also makes you a hero in many ways because
you have now created something that truly can be exposed by an API to the rest of the company.
It makes it easier to integrate to other things, and it makes it easier for your business,
but you can tell them that, for you, it makes it easier for you to do your daily job.
Taking advantage of what large language models can do for us today
to really understand that code, refactor and create natural services based on business value.
So take a look at your code base, take advantage of the large language models that truly understand COBOL,
and build yourself a set of services to make your life easier.