What are the type of file system for Ubuntu,Fedora,Sun solaris?
i.e. windows file system is FAT32/NTFS, what are the type for Ubuntu,Fedora,Sun solaris?

My Ubuntu install uses EXT3 by default.

Fedora also use the same file system as Ubuntu

Sun Solaris 10 now uses a file system named ZFS... really cool. This new technology outdates other filesystems running on UNIX platforms. Their older system was UFS.

And I hear ZFS doesn't stand for anything.

And I hear ZFS doesn't stand for anything.ZFS - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Zfs)
The name originally stood for "Zettabyte (http://en.wikipedia.org/wiki/Zettabyte) File System", but is now a pseudo-initialism (http://en.wikipedia.org/wiki/Pseudo-initialism).

That's right... originally it stood for "Zettabyte File System" but it's just now a vestige.