can you run the same software on each? Yes. In practice, however, remember that linux software is usually manged through a package manager. This means each dis

can you run the same software on each? Yes. In practice, however, remember that linux software is usually manged through a package manager. This means each distro packages each software package to install using their own conventions and formats. Some conventions (such as freedesktop.org guidelines) and formats (both SuSE and RedHat use YUM/RPM) are shared between many distros, others are not. Also many distributions will patch software specifically for their needs and may even have different compile-time options enabled. how large is the difference between base versions (i.e., debian vs. redhat) There are differences: - between how they handle software packages, like I stated earlier - in QA and release policies (what RedHat considers stable and Debian considers stable might be different even for the same package) - in security features (SELinux, grsec, AppArmor, ProPolice, etc.) - in default packages installed (PCLinuxOS ships with KDE, Ubuntu with Unity, Debian with Gnome, etc) - in init systems (Sys V, systemd, upstart, OpenRC) - in available support options - in release schedules and methods (rolling release [Gentoo, Arch, Foresight] vs scheduled releases [Fedora, Ubuntu] vs "when it's done" [Debian]) - Commercial (Ubuntu, SuSE and RedHat) or volunteer/nonprofit (Debian, OpenSuSE, Fedora and most others) - in legal and "ethical" standards (nonfree software availability, availability of software known to be infringing on US patents, nonfree drivers or firmware, etc.) There is an attempt to arrange things logically, so even if you're unfamiliar with the init system on a specific distro -- if you've worked on any other Linux (or even BSD) init system before you should be able to figure things out pretty quickly. Other things, like SELinux, aren't immediately intuitive if you're not familiar with them.