Some 25 years ago, UNIX System Laboratories, Inc, dragged one of the main driving forces of UNIX, the Berkeley Software Design, Inc, to court and sabotaged the most thriving software ecosystem witnessed so far. In the end, three files out of over 18,000 were removed due to possible copyright infrigement, Windows NT gained ground, Linux took off and the Computer Science Research Group was disbanded. This followed a licence change in v7, which forbade efforts like the famous Lion's Commentary on UNIX. How things have changed: the source code for UNIX 8th Ed., 9th Ed. and 10th Ed. has been released publicly for everyone to read and learn.

Skipping back to today, DragonFly BSD 4.8 has just been released. DragonFly began as a fork of FreeBSD 4.8 and is one of the most interesting operating system design efforts since the 2000s, which among other things brought us the wonder that is the HAMMER filesystem.

Also, this.