ACESgrid Hyperwall Reference Material

We are experimenting with setting up a hyperwall for the ACES project. The hyperwall contains an array of flat panel monitors that can be used to display large images split over a matrix of screens or to display multiple related images in a matrix. To display images on the hyperwall we use cool software from Chris Henze at NASA AMES. You can find out more about Chris's Hyperwall work here. This page describes how to

The introduction section below provides a brief technical introduction to the hyperwall system.

Basic setup

The hyperwall consists of a matrix of LCD panels. Images are displayed on the LCD panels by a set of rendering machines. A single controller machine is used to steer all or some subset of the rendering machines. All the machines run X Windows on top of Linux. Two main pieces of software are used. One is a program to compute or display images on each of the rendering machines the other is a program to direct mouse and keyboard events from the controller machine to some or all of the rendering machines. This allows the rendering machines to be controlled in blocks from a single keyboard. Additional small helper script programs are also used. These automate the steps involved in using the hyperwall such as staring up a program to display an image of each of the rendering machines.

The hyperwall can be used to display and pan and zoom around a single very large image spread over the entire wall of displays. This allows images that are many thousamds of pixels across to be viewed at their native level of detail. However, the hyperwall system also allows sets of related images to be viewed simultaneously. This allows the visual identification of correlations between different images.

System requirements

To create a basic hyperwall setup the following hardware and software pieces are needed

OS configuration steps

Compiling the hyperwall software

Displaying a big image over all the panels in the hyperwall

Once the system software is configured on all the nodes you can test the setup by displaying a big image. Links to several test images are given above. The commands steps below describe how to do this on our four x four Dell cluster based hyperwall. This cluster is configured as follows To display a big image over all the hyperwall panels a program called showPaged is used. The showPaged program is run on every rendering machine. It is given a specially preprocessed .ppm image file (known as a .ppm.paged file) as input, the LCD matrix size, and the location in the LCD matrix that the particular rendering machine is responsible for (this location corresponds to the (n,m) number in the IP address matrix). This requires the following steps