Editing Channel Definition Format

{{Short description|XML file format}}
{{other uses of|CDF}}

'''Channel Definition Format''' (CDF) was an [[XML]] file format formerly used in conjunction with [[Microsoft]]'s [[Active Channel]], [[Active Desktop]] and Smart Offline Favorites technologies. The format was designed to "offer frequently updated collections of information, or channels, from any web server for automatic delivery to compatible receiver programs."<ref>{{Cite web| last = Ellerman| first = Castedo| title = Channel Definition Format Submission 970309| work = W3.org| accessdate = 2011-07-08| date = 1997-03-10| url = http://www.w3.org/TR/NOTE-CDFsubmit.html}}</ref> Active Channel allowed users to subscribe to channels and have scheduled updates delivered to their desktop. Smart Offline Favorites, like channels, enabled users to view webpages from the cache.

==History==
Submitted to the [[World Wide Web Consortium]] (W3C) in March 1997 for consideration as a [[Web standards|web standard]],<ref>{{Cite web|title=Microsoft Leads Industry to Standardize on Formats for Internet Push Channels; Submits Channel Definition Format Specification to W3C |work=Microsoft |accessdate=2014-09-13 |date=1997-03-12 |url=http://www.microsoft.com/en-us/news/press/1997/mar97/cdfrpr.aspx |url-status=dead |archiveurl=https://web.archive.org/web/20140913171719/http://www.microsoft.com/en-us/news/press/1997/mar97/cdfrpr.aspx |archivedate=September 13, 2014 }}</ref> CDF marked Microsoft's attempt to capitalize on the [[push technology]] trend led by [[PointCast (dotcom)|PointCast]].<ref>{{Cite magazine|volume=5 |issue=3 |last=Kelly |first=Kevin |author2=Gary Wolf |title=Push! |magazine=Wired |accessdate=2014-09-13 |date=March 1997 |url=https://www.wired.com/wired/archive/5.03/ff_push_pr.html |url-status=dead |archiveurl=https://web.archive.org/web/19991013012158/http://www.wired.com/wired/archive/5.03/ff_push_pr.html |archivedate=October 13, 1999 }}</ref> The most notable implementation of CDF was Microsoft's [[Active Desktop]], an optional feature introduced with the [[Internet Explorer 4|Internet Explorer 4.0]] browser in September 1997.<ref>{{Cite news |last=Lash |first=Alex |title=New Explorer finally here |work=CNET News |accessdate=2015-12-29 |date=1997-10-01 |url=http://www.news.com/SpecialFeatures/0,5,14723,00.html |url-status=dead |archiveurl=https://web.archive.org/web/19990116221408/http://www.news.com/SpecialFeatures/0%2C5%2C14723%2C00.html |archivedate=January 16, 1999 }}</ref><ref>{{Cite news| issue = 757| pages = 315| last = Glascock| first = Stuart| title = IE 4.0 finally ships, to be built into future OS versions| work = Computer Reseller News| date = 1997-10-06}}</ref> Smart Offline Favorites was introduced in [[Internet Explorer 5.0]].

CDF prefigured aspects of the [[RSS (file format)|RSS]] file format introduced by [[Netscape Communications Corporation|Netscape]] in March 1999,<ref>{{Cite book| publisher = O’Reilly| pages = [https://archive.org/details/developingfeedsw0000hamm/page/2 2]–11| last = Hammersley| first = Ben| title = Developing Feeds with RSS and Atom| url = https://archive.org/details/developingfeedsw0000hamm| url-access = registration| chapter = A short history of RSS and Atom| location = Sebastopol| date = 2005| isbn = 9780596008819}}</ref> and of [[history of web syndication technology| web syndication]] at large. Unlike RSS, CDF was never widely adopted and its use remained very limited. As a consequence, Microsoft removed CDF support from [[Internet Explorer 7]] in 2006.<ref>{{Cite news |title=CDF Reference |work=Microsoft |accessdate=2016-02-20 |date=2010 |url=http://msdn.microsoft.com/en-us/library/aa768137(v=vs.85).aspx |url-status=dead |archiveurl=https://web.archive.org/web/20101226233037/http://msdn.microsoft.com/en-us/library/aa768137%28v%3Dvs.85%29.aspx |archivedate=December 26, 2010 }}</ref>

== Example ==
A generic CDF file:
<syntaxhighlight lang="xml">
<?xml version="1.0" encoding="UTF-8"?>
<CHANNEL HREF="http://domain/folder/pageOne.extension"
  BASE="http://domain/folder/"
  LASTMOD="1998-11-05T22:12"
  PRECACHE="YES"
  LEVEL="0">
    <TITLE>Title of Channel</TITLE>
    <ABSTRACT>Synopsis of channel's contents.</ABSTRACT>
    <SCHEDULE>
      <INTERVALTIME DAY="14"/>
    </SCHEDULE>
    <LOGO HREF="wideChannelLogo.gif" STYLE="IMAGE-WIDE"/>
    <LOGO HREF="imageChannelLogo.gif" STYLE="IMAGE"/>
    <LOGO HREF="iconChannelLogo.gif" STYLE="ICON"/>
    <ITEM HREF="pageTwo.extension"
      LASTMOD="1998-11-05T22:12"
      PRECACHE="YES"
      LEVEL="1">
        <TITLE>Page Two's Title</TITLE>
        <ABSTRACT>Synopsis of Page Two's contents.</ABSTRACT>
        <LOGO HREF="pageTwoLogo.gif" STYLE="IMAGE"/>
        <LOGO HREF="pageTwoLogo.gif" STYLE="ICON"/>
    </ITEM>
</CHANNEL>
</syntaxhighlight>

==See also==
*[[Active Channel]]
*[[Active Desktop]]
*[[Push technology]]
*[[Semantic Web]]
*[[List of content syndication markup languages]]
*[[History of web syndication technology]]

==References==
{{reflist|2}}

== External links ==
*[https://docs.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/platform-apis/aa768023(v=vs.85) Introduction to Active Channel Technology]
*[https://web.archive.org/web/20131011020101/http://support.microsoft.com/kb/174055 How to Create Channel Definition Format (CDF) Files]
*[https://www.w3.org/TR/NOTE-CDFsubmit.html 1997 W3 Submission of Channel Definition Format]

{{Internet Explorer}}

[[Category:Internet Explorer]]
[[Category:Push technology]]
[[Category:Windows 98]]
[[Category:Windows communication and services]]
[[Category:Web syndication formats]]
[[Category:XML-based standards]]