Caldera Openlinux
The sco group, inc. nasdaq: scox
http://www.caldera.com
Debian
Debian gnu/linux is a free distribution of the gnu/linux operating system. it is maintained and updated through the work of many users who volunteer their time and effort.
http://www.debian.org
Linux Mandrake
Verisign digital brand management systems customer.verisign, inc. operates intelligent infrastructure services that enable and protect billions of interactions every day across the worlds voice and data networks.
http://www.linux-mandrake.com
Slackware
Slackware
http://www.slackware.com
Suse
Suse
http://www.suse.com