Anyone knows something more about .iso .toast .cdr and .dmg file structure? analysing some images found that each file size can be divided for 2048, so what are the differences in file structure for these file formats? Mac OS X and macOS disk utility provides 4 different options to create disk image files: -Read only (.dmg) (smaller than iso created from windows) -Compressed (dmg) (even smaller than read only dmg) -Read/write (dmg) (same size as iso created from windows) -CD/DVD Writer (cdr) (same size as iso created from windows) Guess apple uses cdr same way that windows uses iso. Snow Leopard uses .iso.cdr as standard output for disk utility in writer option, thus meaning that files should have the same structure (?). Never used Roxio Toast but seems that .iso and .toast could have only different extension. Anyone familiar with this?