This was the distribution that first allowed Linux to start to get popular as it was the first to make it relatively easy for a person that was not already intensely knowledgeable about UNIX to install Linux.
There is not one definitive site for Slackware; there are rather several:
Slackware has not seen as much development attention lately, as it still really is one man's distribution, and many people have found the "a little friendlier still" Red Hat distribution to be easier to install, and Red Hat has certainly taken up the torch in terms of mindshare.
Trying to compare Red Hat and Slackware tends to draw out extremists from both "camps;" the distributions have somewhat different strengths and weaknesses.
The things that have represented long term strengths of Slackware have included:
The ability to install using the UMSDOS files system on a Windows-based system, without need to disturb an existing Windows install;
A clear subset, called ZIPSLACK, that fits nicely onto a Zip disk.
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