inode / index node

Data structure in Unix/Linux filesystems that stores all metadata about a filesystem object—except its name and its actual data contents.
Every file or directory on a Linux filesystem gets assigned a unique integer called an inode number.

struct file_inode { int size; int change time; int group; int permissions; int number of blocks; //Addresses of blocks of file_A on Disk uint64_t Block_Addresses[] = {4, 7, 2, 10}; };

Every time user writes to file, new block is stored at new disk location and addresses is added.
File name(stored on heap), file content(stored on disk blocks).