About The LC Home Page

Details only a programmer could love

Who, When, and Why

This site was started in 1995 as a way to communicate information about Cray's internal electromagnetics tool, LC, to a few users outside of the company. It was created by one of the developers of LC, but now contains contents from a number of LC developers and users.

Technical Development Of The Site

Throughout its development, one of the guiding design principles has been to offer a useful experience for all visitors to this web site. Care has been taken to make the pages viewable by a variety of browsers.

The early versions of the web site were designed for NCSA's Mosaic and HTML 1.0. As web programming evolved and browser capabilities increased, the site was upgraded to provide more sophisticated features while retaining usability for a variety of browsers.

The frames feature of Netscape 2.0 has been used sparingly, providing a table of contents feature for the Users's Guide. As is customary, a non-frames version was provided either automatically to browsers without frames and by choice to those who preferred a single frame.

With Netscape 3.0 came some Java features for the site, including a Java animator and the LC Java wire frame viewer. The animator is a standard Java example applet which displays a set of images in a rapid sequence. The wire frame viewer was adapted from a example applet so it could read LC's native model file format, LCX.

After obtaining WebSpace, a free VRML-capable browser from SGI, an LCX to VRML translator was added to LC, and VRML versions of the models were added. Initially, VRML 1.0 was supported, but later VRML 2.0 (Moving Worlds) was added, although the new capabilities were not used.

In 1997, the Cray Research corporate home page was redesigned using tables for its layout. The relaunch inspired changes to the LC home page, which also began using tables for formatting. The down side to this approach is that non-standard markups are required to keep the pages from appearing scrambled to browsers which don't fully understand tables.

Image Considerations

Care has been taken to minimize download times of the pages. The main strategy is to choose the image format which produces the best compression, as well as reducing the image size, quality, and number of colors. Most of the pages are under 30K in total size, and links which require downloading large files are marked.

To assist optimized browsers, image size information has been added to the HTML reference. Many browsers format and display the page text before beginning download of the images if this information is available. Tables interfere with this acceleration somewhat, although other parameters can mitigate this difficulty.

Alternate text for images is provided for text-only or image-delay browsers. Netscape 4.0 provides alternate text during the image download phase, and as "Tool Tips" when the pointer resets on the image. Somewhat surprisingly, alternative text appears to be becoming more important even as browsers become more capable.

Future Directions

One of the areas that have not received attention is META information, which are tags giving information about the document. This information is mostly used by web crawlers and search engines, but some browsers can display or otherwise use some META information.

Recent efforts include the implementation of style sheets to provide more consistent formatting across platforms and browsers. Some Javascript has also been used to enhance the site.

Experimentation is being done with using VRML 2.0 for visualizing the results of an electromagnetic simulation. One can examine the model and play back animations mapped onto its surfaces.