There are two ways to locate a file on an ISO 9660 file system:
1. to successively interpret the directory names and look through each directory file structure to find the file (much the way MS-DOS and UNIX work to find a file).
2. through the use of a precompiled table of paths, where all the entries are enumerated in the successive contents of a file with the corresponding entries. Some systems do not have a mechanism for wandering through directories, they obtain a match by consulting the table.
While a large linear table seems a bit arcane, you can quickly search without wandering across the disk (thus reducing seek time).