This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I'm not sure what you mean by "linux 8". Linux is an operating system kernel. I think you mean Fedora 8, which is a general purpose desktop OS sponsored by Red Hat.
In the most general terms, Red Hat Enterprise Linux is a fully supported operating system aimed at servers. Fedora, on the other hand, is a desktop OS which is supported by a community of developers.