# Google Developers - Mainframe Modernization Antipatterns (Highlights) ![rw-book-cover|256](https://readwise-assets.s3.amazonaws.com/static/images/article3.5c705a01b476.png) ## Highlights ### Big bang rewrite antipatterns - In a big bang rewrite, you or your team manually rewrite and re-architect the legacy mainframe code into a modern language using modern design patterns. - matching the new system precisely to the original functionality always takes longer than expected. ### Lift-and-shift migration antipatterns - A lift-and-shift migration is an established method of moving an application from one system to another with minimal changes and downtime - you remain locked into the same mainframe ecosystem, but now with an extra dependency on an emulation layer ### In-place modernization antipatterns - In an in-place modernization, you focus on improving the quality, maintainability, and testability of your software while keeping it on your mainframe computers. - Every year the talent pool shrinks, the software platform becomes more isolated, and the vendor ecosystem consolidates.