XML
From Informatics
Useful Resources
http://www.w3.org/TR/xmlschema-0/
caGrid Wiki: Abstract Schema Types
Definitions
XML Schema - a replacement for DTD that defines what can appear in an xml document. This is commonly suffixed by .xsd. Instance Document - refers to the xml that is sent "across the wire". If you do a trace via tcpmon (see tcpmon for details), what you see on in the request and response are the instance documents.