newbie filesystem question

[Mag Gam <magawake gmail com>]

Since there are experts here, I though this would be the best place to
ask the question:

As I understand, ext2 and ext3 we preallocate inodes when a filesystem
is being created. It basically writes "zeros" to the volume.  (please
correct me if I am wrong)

Once the filesystem is created it creates an inode table which keeps
all the inode information. The inode table changes when there are
changes on the filesystem (I/O).

I was wondering, how come some other filesystems have a dynamic inode
table? Where you can have infinite number of inodes?


Sorry, if this is a dumb question. I am trying to learn some Unix basics.

TIA