Push Technology

Five thousand years ago, with the invention of writting, the human species took its first jump towards a technological civilization. The second one came only in the last half of hte XV century, with the invention of press, by Gutenberg. The possibility of reproducing thousands of identical copies of the same document has taken to the creation of the first magazines and journals, a revolutionary concept. But this ocurred in a slow and gradative way: the first scientific journal pressed, for example, was released just in 1665, 200 years after. Although, until today this is the basis of a huge system of divulgation in science and technology, counting more than 300 thousand journals around the world, and that has changed little during the three last centuries.

Nowadays, this scenario is about to change radically, with the development of global computer networks, like Internet, mainly after the explosion of WWW (World Wide Web), that allows for high quality electronic publishing, wiht texts, images, videos, etc. Together, these two technologies have a revolutionary potential many times superior than the invention of press.

WWW is based in an active model of search for information, this is, in traditional Internte navigation, denominated "pull" technology, the user obtains information from different WWW sites, searching for topics of his interest. The huge volume of documents and sites available make the information obtention possible only after a refined search procedure, made with one of the mechanisms existent for this purpose, making the process difficult. Besides that, the continous growth of available information and the necessity of individually visiting the sites is, slowly, making access infeasible, both from the user's and the editor's points of view.

Traditional information media, on their own time, are based in a passive model, this is, the subscriber receives information through a "broadcasting" or transmission system (newspapers, magazines, radio and TV). In Internet this technology already exists, and is denominated "push", also known by "webcasting" and "pointcasting". The solution given by the arise of "push" technology inverts this equation, making Internet reach the final user, delivering information based in a pre-defined interests profile and eliminating search and selection steps.

The "push" system technology was released to the public through commercial software PointCast, in 1996, followed by others like Marimba and the recent Netcaster and Webcaster. The term "pointcasting" was given this name because it is a news transmission point to point, from the generator to the receptor, inversely to "broadcasting" technology that is the emission of standart programs from one point to several ones, like in the case of common newspapers, radio and TV.

The system is constituted, on the subscriber side, by a specialized browser that uses the same basic TCP/IP communication protocol used in Internet, and that receives multimedia material from a specialized transmissor agency (server). Each program offers several information multimedia channels, among them news, entertainment, sports, health and business channels. The program user sets up the channels of his interest and receives the information update according to his choice, with periodic updates. Channels can be made of HTML pages, Java applets, images, videos, sounds or any type of digitized media. The update frequency can be set up by the user and can be continous or periodic, or under demand. The server stores a profile of interests and options for that particular user and sends ("pushes") the new material since the last emission, which is kept in the client's disk, for posterior revision.

In "push" technology, the information is transmited in packets, which exist in many formats. The industry future depends on the success of creating a standart format for all softwares. In relation to the client software, usually is public domain and freely distributed. Nowadays, it is possible to use generic browsers (Internet Explorer, Netscape) to access "push" channels, but usually a specialized client is ussed, like PointCast and Marimba, etc. To implement a "push" service, the information provider needs to install a specific server software, that works together with the client (for example, Castanet is the server name