http://www.slackware-lnx.de/
http://en.wikibooks.org:80/wiki/Evolution_of_Operating_Systems_Designs/Storage:_Mechanisms#DVD-RAM_Disks

x86 (32-bit) Architecture
http://en.wikipedia.org:80/wiki/iXsystems#TrueNAS
http://en.wikipedia.org:80/wiki/List_of_Linux_distributions_that_run_from_RAM
http://en.wikipedia.org:80/wiki/Light-weight_Linux_distribution

S/390 (31-bit) Architecture
ftp://distro.ibiblio.org/slack390/slack390-current/ChangeLog.txt