There is also the other, less known limitation: There is a structure in the ISO image called "path table". For each file in the image the path table provides identifier of its parent directory. The problem is, that the directory identifier is a 16-bit number, which restricts the number of directories to 65535. Content of each directory is written also in a different place, therefore path table is redundant, and intended only for fast searching. Some operating systems (Windows) use it, while the other (Linux) don't. If an ISO image or disk consists of more than 65535 directories, it will be readable in Linux, and in Windows environment all files from the additional directories will be visible, but empty (zero length).