You may participate in the mail lists for the communities by submitting your requests at their respective subscription pages:
CDC Community
The CDC Community work is hosted at Retro1.org. Mail Archives, documentation, running systems, development environments and more are all available here.
- ControlFreaks The ControlFreaks mail list is hosted at h-net.org, part of Michigan State University Department of History and is dedicated to work related to the CDC Operating Systems (NOS / NOSBE / KRONOS) and CDC Hardware.