Slackware Linux is the oldest distribution of Linux that is still actively maintained. The developer, Patrick Volkerding, released Slackware 1.0 in mid 1993 as a customized version of SLS Linux.
The philosophy behind Slackware keeps the distribution focused on stability and security. Nearly all aspects of the distribution can be configured using a text editor or a provided console program. This avoids complex graphical configuration tools and the bugs such programs introduce. Similarly, the package management system does not provide any dependency resolution like RPMs or DEBs. At first this would appear to be a mark against Slackware, however it allows the system to comfortably mix package and source installs. In short, the package system simply tracks files put on the system and assumes you know what you’re doing.
As a result of this philosophy, Slackware is not known as a user friendly or “newbie” distribution. On the other hand installing and running Slackware is often a great learning experience and, thanks to the consistency from release to release, not a skill that must be updated much if at all.