In many of my last few posts I’ve talked about the meaning of the term “open source”. While it may seem like splitting hairs for many, I hope it can be made simpler by applying what I am calling “The CentOS Test”

The Community ENTerprise Operating System (CentOS) project takes Red Hat Enterprise Linux (RHEL), removes all of the trademarked images, etc., and recompiles the code into a separate set of binaries which it then distributes.

For all practical software purposes, there is little difference between CentOS and RHEL.

When thinking about a purchase of the paid or “enterprise” version of something labeled open source software, ask yourself “does it pass the CentOS test?” Examine the license to see if it would be possible for you to take the source code, compile it and distribute it. If you can, I claim it is likely the software is truly open. If not, then you are looking at commercial software, with all of its limitations.

The test explicitly covers the first three criteria of the Open Source Definition. If you can’t redistribute it, access and compile the source code, and create derived works, it ain’t open.