When you first start using CoCalc, you will see a banner saying
“Upgrade this project, since it is on an unpaid trial server and has no internet access.”
To remove the warning message from the top of your project, at least one collaborator must upgrade the project to run on members-only hosting and have network access.
CoCalc will never charge you, except after you explicitly purchase a subscription or course package.
Reasons for purchasing a subscription¶
The Purpose of CoCalc is to make it easy to use SageMath (and other open-source software like Python, R, Octave, Julia, LaTeX, etc.), collaboratively and to generate a stable revenue source to hire full-time developers to develop CoCalc and ultimately SageMath.
Subscription revenue is currently enough to pay for server infrastructure but not enough to cover employee costs. This means the company behind CoCalc will eventually no longer be able to operate the service. See http://wstein.org/talks/2016-06-sage-bp/bp.pdf for more info about the challenges of funding SageMath development.
A couple of users abused CoCalc to attack other servers on the internet. That triggered a complete shutdown of the CoCalc website by our hosting service provider. To avoid that from happening again, we had to disable outgoing connections to the internet. With such an “internet upgrade”, you can again download files from other servers, install software packages that load from other servers, use
git in a Linux Terminal to work with GitHub, etc.
Subscribers get higher priority on feature-requests and much more involved support responses.
Members only hosting¶
The free servers are of lower hosting quality, sometimes overloaded and periodically restarted. They are cheap Google preemptible instances. A side effect of the cheapness is that the underlying server of your trial project is randomly restarted at least once every 24 hours.
You can purchase additional compute, memory, and storage resources. (see Project Upgrades)
Fund improvement of CoCalc¶
Improvements are made daily! You can follow CoCalc’s development at https://github.com/sagemathinc/cocalc/
Support those who cannot afford to pay¶
When you get a paid subscription, or donate, you help fund the free-tier offering for those who can’t afford a subscription. We all know of some countries (and plenty of individuals in every country) that are going through extremely difficult financial times.