XML or Extensible Markup Language is a subset of
SGML or Standard Generalized Markup Language.
In essence, XML allows anyone to create content
and then describe that content in a separate file. The document description
and the content can be rendered as a Web page, parsed by a script, and
manipulated in a wide range of ways without consideration given to the
computer system, file system, data format, or software program used by the
As a result, XML promises to allow data to be
interchanged more easily than other types of formats.
Because much of XML is in ASCII, the lowest
common denominator of data, created from a standard PC keyboard. XML only
uses characters that are part of the standard ASCII set. None of the
control or special characters that bedevil people unfamiliar with different
systems are used in XML. (Unicode will be supported going forward,
XML, therefore, can be used to create
interactive Web sites and services.
XML can dynamically link data stored in a system
with an application with fewer file conversion and technical headaches.
Because of the tags in an XML document, files
sizes can be 50 percent larger than native file formats.
It is a mechanism for creating distributed
processing and Web services
SOAP, WSDL and UDDI (Universal Description,
Discovery and Integration) are important to Microsoft’s distributed
processing strategy. Microsoft is effectively ignoring or sidestepping
CORBA, Java RMI plus Enterprise Java Beans and other remote procedure call
XML-based SOAP is Microsoft’s way of having
standard and open interoperability between Windows clients and servers and
other application platforms such as OS390, HP / UX, Solaris, and the
Because of XML, SOAP is a plain text
environment, so the data can be readily accessible to a knowledgeable
XML allows metadata interchange. As a result,
XML is moving into search, sitemaps, and distributed authoring. (RDF or
Resource Discovery Framework databases can automatically filter and
classify mail, ftp, telnet, http, and other messages).
With XMI (XML Metadata Interchange) definition
vendors can tag specific files so data transformation can be automated; for
example, between a CAD file and a parts order on a different system.