Slackware is the oldest Linux distribution that is still actively maintained and supported.
It was released in 1993, shortly after the the release of its parent SLS Linux, according to many, the first real public Linux distribution.
Leaded since the beginning by Patrick Volkerding, Slackware has its own place carved in the stone of Linux world.
It has a devoted supporting base, both for its age and its no frills logic, which somehow is a glimpse of its ancient origins. Slackware is one of the few distros that features BDS like init scripts (SysV is still supported), an essential and somehow primitive packaging system (tgz), a text based semi-manual installation procedure and few custom configuration tools.
Many love it because they know it and appreciate its essential structure, others simply find it too difficult compared to other popular distros and avoid it.
Chronology of Slackware releases
n/a (1993-07-11) Kernel 0.99pl11A, "SLS-like system" pre-announced on comp.os.linux. Patrick's email was posted on the Cleveland FreeNet, sponsored by CWRU.
Slackware 1.00 (1993-07-17) Kernel 0.99pl11A, Announced on c.o.l. TeX had to be installed from the SLS T-series floppies. With: gcc-2.4.5, libc-4.4.1.
Slackware 1.01 (1993-08-04) Kernel 0.99pl12A, with: ksh, tcl, XFree86 1.3.
Slackware 1.0.2 (1993-09-05) Kernel 0.99pl12, with: emacs 19.19, games, change in versioning 1.01 -> 1.0.2.
Slackware 1.0.3 (1993-09-15) Kernel 0.99pl12, with: pine
Slackware 1.0.4 (1993-10-01) With: Tin/XView updates
Slackware 1.1.0 (1993-11-04) Kernel 0.99pl13. Disk sets: A, E, IV, OI, OOP, TCL, X, XAP, XD, XV, Y.
Slackware 1.1.1 (1994-02-xx) Kernel 0.99pl14. 51 floppies. XFree86 2.0, libc 4.4.4. TeX
Slackware 1.2 (1994-03-27) Kernel 1.0 "Installing all takes about 200MB"
Slackware 2.0 (1994-06-25) Kernel 1.0.9, 1.1.18 Also Morse Communications "Slackware Pro"
Slackware 2.1 (1994-11-15) Kernel 1.1.59, 65 floppies, plus boot & root disks
Slackware 2.2 (1995-03-??) Kernel 1.2.1
Slackware 2.3 (1995-05-??) Kernel 1.2.8, libc 4.6.27, XFree86 3.1.1
Slackware 3.0 (1995-09-30) Kernel 1.2.13, 1.3.1 First ELF. Walnut Creek CDROM.
Slackware 3.1.0 (1996-07-03) Kernel 2.0.0 Called "Slackware'96". libc 5.3.12.
Slackware 3.1.0 (1997-01-13) Kernel 2.0.27 Also called "Slackware '96"
Slackware 3.2.0 (1997-02-17) Kernel 2.0.29
Slackware 3.3.0 (1997-07-11) Kernel 2.0.30
Slackware 3.4.0 (1997-10-14) Kernel 2.0.30
Slackware 3.5.0 (1998-06-09) Kernel 2.0.34, libc 5.4.44, XFree86 3.3.2.2
Slackware 3.6.0 (1998-10-28) Kernel 2.0.35 "Recommend 500MB for full install"
Slackware 3.9 (1999-05-17) Kernel 2.0.37 Co-released with 4.0
Slackware 4.0.0 (1999-05-17) Kernel 2.2.6, 2.2.7 "Recommend 1GB for full install", XFree86 3.3.3.1 First kde 1.1.1
Slackware 7.0 (1999-10-25) Kernel 2.2.13 First glibc2, "recommend 2GB partition", Version jump from 4 to 7.
Slackware 7.1 (2000-06-22) Kernel 2.2.16, XFree86 3.3.6. First gnome.
Slackware 8.0 (2001-06-28) Kernel 2.2.19, 2.4.5, XFree86 4.1.0, kde-2.1.1
Slackware 8.1 (2002-06-19) Kernel 2.4.18, XFree86 4.2.0, kde-3.0.1, gnome-1.4.1, First mozilla
Slackware 9.0 (2003-03-20) Kernel 2.4.20, gcc-3.2.2, XFree-4.3.0, kde-3.1, gnome-2.2
Slackware 9.1 (2003-09-25) Kernel2.4.22, GCC 3.2.3 (with GCC 3.3.1 as an alternate choice), GNOME 2.4.0, and KDE 3.1.4. Slackware 9.1 uses the stable 2.4.22 kernel, but is 2.6.x ready.
Slackware 10.0 (2004-06-22) Kernel 2.4.26, gcc 3.3.4, X11R6 (xorg) replacing XFree86 for the fist time, KDE 3.2.3, Gnome 2.6.2
An overview of Linux Distributions: companies, entities, individuals and their efforts.
OS Guide: SlackWareThe OpenSkills Guide for experienced System Administrators: SlackWare