A framework to integrate synchronous and asynchronous collaboration

For the last decade, the research in CSCW (computer supported cooperative work) has been focusing on synchronous collaboration, which requires the participants involved in common tasks to remotely share computer display workspaces simultaneously without leaving their workplaces. However, to support truly global cooperative work, asynchronous collaboration is equally prominent, in order to accommodate the participants who may not be available for the synchronous CSCW session. These participating individuals, whether working synchronously or asynchronously, may be mobile and may have to connect to and disconnect from the session repeatedly with ubiquitous systems. We describe a framework for asynchronous as well as synchronous collaboration. The framework provides facilities to transfer the screen images or frame buffers of the ongoing CSCW session to remote users, allowing the available participants to share the view and the control of the session simultaneously, and to record the screen images or frame buffers for the absent participants to retrieve and playback the session at a later stage with VCR-like control (i.e. fast forward, rewind play and stop). The frame buffers are transferred and recorded in units of rectangles containing pixel values of the screen images. These rectangles are platform independent and can be dynamically directed to and displayed by heterogeneous systems such as X Windows or Windows NT, or by Web browser such as Netscape