Slackware is a lightweight distro designed to be UNIX-like and work with older hardware. It is produced by Patrick Volkerding since 1993, and is the oldest maintained Linux distro. The original SUSU was built using Slackware.
slackware
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W http://en.wikipedia.org/wiki/Slackware
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The name Slackware was chosen because it was humorous, and at a time when the project had not become widespread. The term was also a private joke.
Slackware became more than a side project when Patrick Volkerding's artificial intelligence instructor at the University of Minnesota asked him to produce a version of the OS for the computer lab to use. Later, Slackware was hosted on the universities servers and grew rapidly from there.
Initially the OS was slanted toward non GUI, but today several desktops such as Gnome, KDE, and others can be installed with guides readily available by internet search.
Over the years Slackware has been the basis for many other distros such as SUSE.