How the UNIX file system forms a structure with nodes

I'm trying to understand how the UNIX file system works with regards to inodes. As I understand, a directory is represented as simply a table with an entry of the form [name:inode] for every subdirectory or file.

Where I am confused is how these directories form a structure. If i had a directory 'root' containing a subdirectory 'home' which contains a file 'file.txt' then i believe the root directory would have an entry ['home':(homes associated inode)] but then how does this link to the 'home' directory table?

Any help or guidance would be much appreciated, Ben

Solution

Your understanding is mostly correct. Here's a picture that might help. I'm going to assume that the root directory is known to be inode 1. So we might have:

inode 1:

type: directory
contents:
    usr       17
    etc       49
    home      57

inode 57:

type: directory
contents:
    dmr       201
    scs       857
    ben       981

inode 981:

type: directory
contents:
    .bashrc   1045
    projects  1191
    file.txt  2043

inode 2043:

type: file
contents:
    This is
    my text file.

Here I've shown the situation that the full path (or at least, a full path) of your text file is /home/ben/file.txt.

(I've also made one big simplification. Typically, a file's contents are not stored in the inode, but rather, in other disk blocks, with the inode containing pointers to those other blocks.)