Have a question regarding PDM, and where it actually stores its files & vault - or even how it stores them

Right clicking the vault on a computer other than the server it is located on, will give a size in MB for how many files are in it. In my case, thats 17101MB in total, and i'm assuming that if everything in it is checked in, that nothing is stored locally to my client PC? Is the PDM vault view simply a link to view whats on the server, with the ability to locally cache files when checked out?

The other question is server-side, and relates to where the files are actually stored on the server. Not only that, but whether there is actually a folder I can look into to see all of these files, or if they're stored using some other method?

Thanks for the help