domain name / host name

[Christoph Harder]

Hello,

I've got another newbie question.
In the setup one may provide a hostname and domain for the computer.
How and where is this information exactly used?

Hostname is pretty self-explaining, though I'm not sure, can it be used to access it like in a local windows network e.g. \\mycomputer\shareddisk\ e.g. after setting up an NFS share?

And domain, is a real domain name required/recommend? One that is resolvable through DNS?
And what happens if there are multiple domains hosted on a single server'?
Or is this more like a Windows Workgroup?

Thanks in advance. In case this is somewhere in the manual, it would be nice if you can point me too it, I just couldn't find it.

-Christoph