Quick rundown various Linux and BSD operating systems: Answered
1. Debian - one of the older base distributions and currently one of the most popular. Uses the "apt" package manager for software installation. Excellent server distribution.
2. Fedora - the free community edition of Red Hat Linux. Sponsored by Red Hat Linux. Uses the "rpm" package manager for software installation.
3. openSuse - sponsored by Novell, originally developed largely in Europe.
4. Mageia - fork of an older distribution called Mandriva Linux.
5. PCLinuxOS - also a fork of Mandriva. Looks to provide out-of-the-box support for graphics and sound cards.
6. Red Hat Enterprise Linux (RHEL) - based on Fedora, RHEL includes many enterprise-level enhancements and is supported Red Hat corporation.
7. CentOS Linux - free enterprise-grade operating system that is built from the same source code as RHEL without the proprietary enhancements or support from Red Hat.
8. Puppy - very small Linux operating system that boots the OS and applications completely into RAM. Can operate on older computer equipment. Excellent for use in emergencies and to recover data from hard drives.
9. FreeBSD - operating system that is based on BSD code.
10. Ubuntu Linux - easy to use operating system that is based on Debian Linux. Supported by the Canonical corporation. Ubuntu means "humanity to others". Excellent server distribution.
11. Linux Mint - currently one of the most popular distributions, based on Ubuntu Linux. Looks to provides complete experience by including browser plugins and media codecs (ie: Flash) upon installation. Excellent desktop distribution. Also comes in lightweight editions for older hardware
12. NetBSD - based on BSD code. Can be run on a wide range of hardware. Currently there are 57 different hardware architectures that can run NetBSD.
13. OpenBSD - based on BSD code. Source code built from the ground up with security first and foremost as the goal. Ships "secure by default", that is, all non-essential services are disabled. OpenBSD has embedded cryptography throughout the operating system; it utilizes OpenSSH, Pseudo Number Random Generators, cryptographic hash functions, cryptographic transforms and crypto hardware support.
14. ClearOS - server and network distro designed for small businesses. Based on Red Hat Linux. Web-based interface controls anti-virus, anti-spam, VPN, content filtering, bandwidth manager, file services, SMTP services, print services, SSL certification, and web services.
15. Kali Linux - distro that specializes in penetration testing and security auditing. Over 300 penetration testing tools. Based on Debian Linux.
16. Lubuntu - lightweight version of Ubuntu Linux for older computers and netbooks.
17. Gentoo - highly customizable distro that uses a package system called portage written in Python. Mascot is Larry the Cow.