Users select the channels to which they want to subscribe, and the tuner does the rest. Each channel appears on the screen as an icon, in the same way as a word processor or spreadsheet package. The first time a channel is selected, the transmitter downloads all the information contained within it to the user's PC, where it is stored on the hard disk. From then on, each time the user accesses the site, only information that has changed since the previous visit is transmitted. This limits the amount of connect time and reduces the amount of network resource required.
It is this feature that puts Castanet ahead of anything else on the market and has attracted the attention of companies such as Netscape and Microsoft. It enables users to change fundamentally the way they use the Web and overcome one of its major limitations: lack of speed.
When an update is required, the PC sends a request that contains an index of all the information about the channel held on the user's hard disk. The transmitter on the server then compares this index with its latest version and sends any changes that have occurred since the last update. This process is known as differential updating and Marimba has applied for a patent on it. One area of concern raised by the new technology is security. With computer viruses now rife, how comfortable are people about letting self-updating software have access to their hard disk? Marimba has overcome this concern by allowing channels to access only a defined area of a user's disk. The software's security has been designed to ensure that the information downloaded from a channel cannot interact with any other information stored on the PC.
Kim Polese was the one-woman marketing force behind Java. Chief technical officer Arthur van Hoff and senior engineer Jonathan Payne were co-architects of Sun's Hot Java browser product, while senior engineer Sami Shaio developed Java's security and development tools. It is this intimate knowledge of the new and very powerful language that has allowed Marimba to push the language beyond what anyone else has achievedn