Introduction

AMarquee is a system for broadcasting information between Amigas and computers running Java. It uses a server-hub information storage model, where any AMarquee program may upload information to the central server, and other AMarquee programs may download it. Information is stored on the server in a filesystem-like structure, with each client given its own "directory" in the tree. Each client may read or write to its own directory on the server, and may read the directories of the other clients (assuming they allow it access).

The AMarquee system was designed in such a way that "polling" of information to detect updates should never be necessary. Instead, each client may subscribe to a set of entries in the server, and whenever the subscribed data is updated, the client will be notified of the change. This technique helps keep bandwidth usage as low as possible.

As alternatives to the information-storage model, AMarquee features a message-passing model and a direct-connect model. You may now easily pass data messages to other clients, through the AMarquee server, or connect directly to other AMarquee clients and send data straight to them, without bothering the server.

Also, the AMarquee system is heavily multithreaded. A client-side thread is started in the background for each connection made with amarquee.library, and a new server thread is created on the server for each connection received. This multithreading allows the user program to do other things while data is being sent or received, and avoids bottlenecks on the server computer. The multithreading is completely transparent to the user program. Furthermore, with AMarquee-java-package, no socket programming knowledge is necessary. All the user's code needs to do is to instansiate the QSession class, add a listener for AMarqueeEvents and implement the AMarqueeListener methods. Then the methods will be invoked when data arrive. It's working like any JavaBean or the AWT in Java 1.1.

The server part, AMarqueed, is currently only available for the AmigaOS. A suitable host to connect to is qamitrack.tibb.at.

(c)Håkan Parting 1998. Last update 16th June 1998