CDF

Channel Definition Format, CDF, is an open specification that permits a web publisher to offer frequently updated collections of information, or channels, from any web server for automatic delivery to compatible receiver programs on PCs or other information appliances.  CDF was posted by Microsoft as a Note to the W3C in 1997 and represents one of the earliest applications of XML. Since CDF is a Note, and was not authored by a standards body, it is a defacto standard, not a true standard.

The definition of CDF consists of the various XML elements.  When downloaded to a client, CDFs act as a local index to its channel's available content. For example, a receiver program can present the implicit hierarchy in a CDF within a channel selector.

The CDF contains the following major elements:

• Channel - defines a channel
• Item - defines a channel item, a unit of information which is available from a channel
• UserSchedule - reference to a client/user specified schedule
• Schedule - defines a particular schedule
• Logo - defines an image to represent a channel or channel item
• Tracking - defines user tracking parameters of a channel
• CategoyDef - defines a category, possibly as a child category of another category