Push Technology Products

by Matt Shea

While there are many push applications that are available from different developers, only a few seem to have an influence on the industry, and keep popping up in the discussions of push technology. These are Netscape’s Netcaster, Marimba’s Castanet, Microsoft’s IE 4.0, and Pointcast.

Marimba Castanet http://www.marimba.com

Marimba was started, by a few of the core employees of the Java project at Sun Microsystems, to provide technologies to help deploy Java applications to users.

Their product, Castanet, uses a transmitter/tuner model to provide subscribers with channels. A channel can either be a web page in HTML or Java applet/applications. The user selects which channel they want to subscribe to through the tuner, which is an application that is run locally on the user’s machine. Castanet supports automatic updating, through the use of an Automatic pull mechanism, which appears to the user that the information is being pushed to them from the server. Castanet supports differential downloads, which will only transmit the difference of the newly updated content, to help conserve bandwidth. Marimba also provides an application called Bongo, which is used in the creation of channels. Marimba’s main area of focus seems to be on Java Applications. When a user subscribes to a Java application, a current version is downloaded and stored locally on the user’s hard drive. The next time they go to run that application, it will load instantly, not needing to re-download it over the Internet.

Marimba system architecture http://www.marimba.com/datasheets/castanet-ds.html

Marimba follows a transmitter/tuner model, where the tuner is a piece of software that sits on the user’s machine and makes requests to the transmitter. The transmitter is provided by Marimba, which is how they make money, and you can also deploy repeaters to help relieve the server from too many requests.

Marimba is curr ently being included with Netscape’s Netcaster, with their channel tuner. http://www.news.com/News/Item/0,4,10866,00.html?latest

Netscape Netcaster http://www.netscape.com

Netcaster is the last portion of the Communicator suite from Netscape, and it is the component that deals with the pushing of channels that the user is interested in. Netcaster provides and interface so that the users can select channels, and set properties on when to update the content. As you can see, Netcaster using the automatic pull paradigm as well. One of Netcaster’s main pushing point is that is uses existing Internet standards of HTML, JavaScript, and Java, in contrast to Microsoft’s CDF format, which it will support in IE 4.0 for push content. This will allow content providers to use existing web servers for their information. Netcaster also includes Marimba’s Castanet technology bundled with it, and has struck deals with Major content providers like ABC News, HotWired, CNNfn, Time Warner, ZDNet, Gartner Group, and CNET. These two aspects should give Netcaster enough support to gain a significant portion of users. Unfortunately, for Netscape, Netcaster has been delayed repeatedly, and still has not been released as of June, for which is was promised.

http://www.infoworld.com/cgi-bin/displayStory.pl?97065.enetcast.htm http://www5.zdnet.com/zdnn/content/zdnn/0604/zdnn0007.html

Microsoft’s Internet Explorer 4.0 http://www.microsoft.com

Just like Netscape, Microsoft has decided to include push technology in the latest version of it’s web browser. Unlike Netscape, Microsoft has proposed a new language to help developers and publishers create and distribute information to readers automatically. The new format, called CDF (Channel Definition Format), has been submitted to the World Wide Web Consortium to become an Internet Standard. Originally, this format would make publishers choose between supplying a Netcaster friendly version of their content, or a CDF version of their content. Only recently has Microsoft added an extension to the CDF format, that would allow Netcaster to view CDF channels, without Netcaster being extended. It is obvious that Microsoft recognized that it could not force publishers to choose between the two, so it made it easy for them to choose CDF, since it would allow readers to view from both browers.


CDF allows the publishers to schedule when an update of their content will happen on the user’s machine, transparently, so that they don’t have to setup it up themselve. Microsoft has also made deals with large content providers and other push technology companies including PointCast, BackWeb, and Tibco. Due to Microsoft’s large size and deep pockets, it is obvious that they will have some success in this area.

PointCast http://www.pointcast.com

PointCast was the first push product/publisher to come out on the market. PointCast provides both the client/tuner and the content of news type information. PointCast has made deals with major content providers like e CNN, CNNfn, Time, People and Money Magazines, Reuters, PR Newswire, BusinessWire, Sportsticker and Accuweather. PointCast also has some major local newspapers. One of the problems with PointCast is the enormous use of bandwidth that it consumes. PointCast has tried to solve this problem, and others in the newest release of PointCast 2.0 beta.


PointCast is also one of the Major partners with Microsoft, and decided to change from their own proprietary language, and will now publish content using Microsoft’s CDF format. PointCast will also be included in IE 4.0, making it easy for users of this browser to subscribe to PointCast Channels. PointCast is also allowing everyday users to publish their own channels, through their Connections program. One problem with this though, is how to let people subscribe to the thousands of channels that are going to be produced, and is analogous to the current problem of finding personal web pages on the Internet now. PointCast has made a deal with Excite to provide search capabilities for PointCast Channels.



There is a definite decision that companies who want to publish using push technology have to make, either to support Netscape’s technology or Microsoft’s CDF format. It is clear that Netscape and Marimba are betting on Java applications and normal web pages as being the future for push technology. This might be due to the fact that they make money through the sale of their server technology. Microsoft and PointCast, on the other hand, are trying to pull people to a specific platform, and use PointCast as a means to subscribe to push channels. This too is probably due to the sources of income for the two companies. Microsoft makes a majority of it’s money from the sales of operating systems, and would want people to use IE 4.0 on Windows 95 or NT. PointCast on the other hand makes it’s money from user’s eyeballs seeing the advertisments that they bundle with the content that they provide. Microsoft, with it new addtion to the CDF format, should make it easier for publishers to choose, and Microsoft to take an upper hand.


One the major problems with the products today, is the interface for users to subscribe to channels, and the channel metaphor itself. Channels are too narrowly defined, and don’t really represent a Channel. An analogy would be on a specialized cable TV channel, like ESPN, the current push “channel” metaphor is more like a certain show on the channel. I.e you would subscribe to the show on basketball at 8:00pm at night, but you would not get to see the other programs that you might be interested in. The current push channel metaphor has this problem, that the user still has to find the channel that they are interested in, and it is not presented to the user if they subscribe to a channel with a similar interest. What is needed is something like a network agent, that will scan all the channels, and based on your profile, provide a list of possible channels that you might be interested in.

A look at channels and CDF