Offering a free clone of Red Hat Enterprise Linux turned out not to be such a simple matter after all.

The CentOS project aims to reproduce Red Hat's tested, supported, and certified version of the operating system, without its per-server subscription fees. Because RHEL is open-source software, it's theoretically possible for an outsider to select the same software packages, apply the same patches, and produce a version of the Linux product that works the same.

But several lead programmers...