How are XML documents stored on a computer?

[yellow_mongoose]

I know this isn't a traditional question for the XML section, but I'm still learning the basics of computer science and there's a lot of stuff I don't know. I have read that documents are stored as groups of records in a sequence, either accessed sequentially or using indexes or hashing. How does this apply to XML documents, which have a tree structure? I still don't quite understand the low level details of how files are broken down into records to be stored on a computer.

[oracleguy]

XML files are stored as plain text, you can them open them up in any text editor.

Are you asking about how the computer stores data in the filesystem or how the data in an XML file constructed?