dir entry contains a number and an inode; that inode is a reference to a table -- the inode is both that hnumber and the data structure stored on disk. The OS keeps in memory all the inodes currently in use. The inode contains the about the file (owner, group owner, various times, where the file is stored on the disk, a reference to blocks, a double-indirect block, a triple-indirect block, count of number of hard links to the inode) except the name of the file.

inode and all files associated with the inode are deleted when the count in the inode is == 0