Encyclopedias.  We have all heard of them I assume.  Why aren't those those volumes of big books that are to be found in the library that can consist of seemingly a million editions for each volume for each letter of the alphabet.  And those books can be heavy as far as I remember.  Well advance to the technological and internet age of the future that seems to be here now when it comes to computers and technology.  Now one no longer has to go to the library at their local library down the block to find that encyclopedia.  Now there is the file extension library that you can look up online without ever having to leave home, or at least without ever having to leave a computer.  And in case you are wondering what a file extension library is you can find out all about it at the file extension library website. They are a data formats encyclopedia. You can find information about VOB file extension and information on how to open .vob files at their website. You can also scan your computer for vob errors as well at their website. And in case you could still be wondering what a vob file is, their website says it has something to do with being a movie file for those dvd formats. The file extension library also has a top twenty file extension listing where you can read all about a lot of file extensions that I have never heard of or even knew existed. With file extension library, reading about those file extensions has never been easier.