As a component of Visual Area Networking (VAN), OpenGL Vizserver® consists of industry-leading graphics capabilities driven by Silicon Graphics® scalable visualization systems and Silicon Graphics® workstations that are transparently coupled with existing desktop computers. Powerful multi-user systems at the core of a departmental or enterprise VAN solution can support an unlimited number of clients per collaborative session. With the Silicon Graphics® Onyx4™ systems, support for multiple Scalable Graphics Capture (SGC) cards accelerates readback performance and overall frame rates to as high as 60 Hz. Silicon Graphics Prism®, Silicon Graphics® Tezro®, Silicon Graphics® Octane2™, Silicon Graphics® Octane®, and Silicon Graphics Fuel® workstations can be combined with OpenGL Vizserver to create personal collaboration systems. The desktop clients currently available include any SGI® desktop system running the IRIX® OS 6.5.11 or greater, as well as systems running Linux®, Microsoft® Windows NT®, Windows® 2000, Windows® XP, and Windows® XP Tablet PC Edition, and Mac OS X, and Sun® Solaris® systems running version 2.5.1 or greater

OpenGL Vizserver has two major functions--to provide application-transparent remote access to high-end graphics resources and to enable application-transparent collaborative visualization functionality to multiple simultaneous users.

As a Remote Access Tool

With OpenGL Vizserver, a visual serving session is initiated from a desktop client with a TCP/IP-mediated request to the server for access to a graphics pipe on an SGI Onyx family system. After user authentication using standard UNIX® password security (Kerberos or DCE authentication available through SGI Technology Solutions, subject to export compliance restrictions) or Linux PAM (Pluggable Authentication Modules), a configuration file is tested for date-and-time allocation for that user. If a graphics pipeline is available on the Onyx family system or nobody is logged into the Silicon Graphics workstation, a session is initiated via a console window that appears on the remote workstation. All standard OpenGL® graphics programs executed from this shell will function in an application-transparent manner under the control of OpenGL Vizserver, with their output being routed to the remote display.

As the OpenGL programs complete their delivery of graphics commands to the pipeline, a readback is performed from the graphics frame buffer, and this image is compressed and sent across the network using standard TCP/IP methods. The client application running on the remote workstation decompresses the image and displays it using standard low-overhead techniques. This results in the client experiencing the full 3D graphics acceleration delivered by the remote graphics pipe. Mouse and keyboard events specific to the application are collected on the client and sent to the server, where they are acted upon by the application as if they were locally generated. Since the remote application control and image display take place in an application-transparent manner at the system level, standard OpenGL applications can utilize the OpenGL Vizserver transport without modification.

As a Collaborative Visualization Tool

VAN is a concept that allows users to interact with visualization supercomputers using any client device, individually or in collaboration with others. It removes the requirement that data, software applications, and advanced visualization features be available locally to each user and allows diverse teams of people, no matter where they are, to visualize and interact with data in ways never before possible.

In a collaborative environment, a local or remote "master" initiates an OpenGL Vizserver session on the visual server in collaborative mode and gives that session a name. Remote collaborators then join that session just like they were accessing a remote visualization resource. Applications can be started by the master or remote collaborators at any time, and remote collaborators can join or leave a session at any time. Application control is shared between the two users, with only a single mouse click needed to select a user as the person controlling the application. The master also has the ability to moderate who has control of an application--a very useful capability when multiple remote users are each trying to take control. Until each user logs out of the session, they all see the same results. Note that applications started outside of the OpenGL Vizserver session remain private to the individual users.

Advanced Capabilities
OpenGL Vizserver supports advanced capabilities demanded by technical and creative users. Chief among these is support for stereo visualization and large-format and multi-pipe applications on SGI client systems. These capabilities allow remote users to become surrounded by and immersed in their data just as if they were in an SGI® Reality Center® facility for a local collaborative session. It also allows users to select the level of compression they want to use so they can maximize their interactivity over a wide range of network speeds.

Visual Area Networking

Solving the biggest problems requires the best minds, but what happens when those minds are geographically dispersed? And what happens when multiple copies of data are passed around, meaning teams aren't even sure that they're all looking at the same thing? VAN introduces the concept of storing and processing the data in one place, where users can interact with it using any client device.

OpenGL Vizserver is the enabling software for Visual Area Networking. It offers shared control of the application, data, and advanced graphics capabilities between a remote user, as described above, and a user sitting at the SGI Onyx family server. This allows multiple users to work together concurrently in a shared context, so they can make better decisions in less time than a single user or multiple users working serially.