First, read this: Hazards And Safeguards for Software Rewrites. This is an infuriating article. The first part is nonsense. I wonder if it's intended to be read ironically? Maybe it's a list of bad ideas? Skip straight to the Safeguards for Rewrites section. It's really good.

Also, this Characterization Testing …

Some years ago--never mind how long precisely--having little or no money in my purse... I had a great chance to do some Test-Driven Reverse Engineering on a rather complex C program. I extracted test cases. I worked with the users to gather test cases. And I rewrote their legacy app …

http://pythonsweetness.tumblr.com/post/64740079543/how-to-lose-172-222-a-second-for-45-minutes Here an important lesson.

Code Rot is Real. It Leads to Subtle and Expensive Bugs.

Claiming that code cleanup is just pointless "gold plating" is the kind of thing that can drive a company out of business.

After talking about some experience with legacy modernization (or migration), I received information from Blue Phoenix about their approach to modernization.

Before talking about modernization, it's important to think about the following issue from two points of view.

Modernization can amount to nothing more than Paving the Cowpaths.

From a …