XML is an excellent method of expressing policies. It has the advantage of being human readable, while software can process it. In its simplest form, XML is text surrounded by tags, in much the same vein as HTML. In fact, as of HTML 4.0, HTML is defined as a specific set of XML tags.
Tags are expressed by a pair of angle brackets (< and >) with text in between. XML tags always come in pairs, with an opening tag containing only the angle brackets and a closing tag using angle brackets and a slash. For example, an ILM field can be described in XML as:
<ILM> Some ILM Policy </ILM>
XML allows for hierarchical structures through the use of nested tags. This allows for very complex ...