Ubuntu - Wikipedia
https://en.wikipedia.org/wiki/UbuntuUbuntu is built on Debian's architecture and infrastructure, and comprises Linux server, desktop and discontinued phone and tablet operating system versions. Ubuntu releases updated versions predictably every six months, and each release receives free support for nine months (eighteen months prior to 13.04) with security fixes, high-impact bug fixes and conservative, substantially beneficial low-risk bug fixes. The first release was in October 2004.
1.1. What is Ubuntu?
https://help.ubuntu.com/lts/installation-guide/s390x/ch01s01.htmlUbuntu is a complete Linux operating system, freely available with both community and professional support. The Ubuntu community is built on the ideas enshrined in the Ubuntu Manifesto: that software should be available free of charge, that software tools should be usable by people in their local language and despite any disabilities, and that people should have the …