As I understand it, yes, yum is redhat specific,
mandrake has urpmi and SuSe has its own version.
(can't remember what its called")

Debian, (of which knoppix is a version) uses something called apt-get, which is similiar to urpmi except that debian doesn't use rpm packages, they perfer a package format called deb.

you could no doubt compile yum to work with different distro's, but I don't know how you would go getting it to work with the distro's native package setup, for example, the default yum will not understand mandrakes package setup.

There have been some conversions to get apt-get to work with other distro's, for example Mandrake has an rpm for apt-get that will work for mandrakes packages, but I have not seen anything for yum.

rgds

Franki