What exactly is an inode as pertaining to filesystems?

Question

As I understand them, apparently an inode basically points to the beginning of a file stored on disk. But it also seems that directories have the same functionality as well (i.e., they store the addresses of other files). I was wondering then, why is it useful to have an inode array around, with a bunch of inodes that point to files when already the directories do that as well?

-> edit: I was also wondering where "file headers" and "bitmaps" came into the picture as well

Thanks :)

Answer 1

An inode the a data structure that contains information about a file. You might be thinking of inode numbers which are indexes into a list of inodes.