VorTeX (available in support/vortex) is a package of programs written at the University of California at Berkeley, and was described by Michael A. Harrison in ``News from the VorTeX project'' in TUGboat 10(1), pp. 11-14, 1989. It includes several nice previewers and some emacs modes for TeX and BibTeX. The VorTeX distribution is not maintained, and now looks distinctly long in the tooth (it was never upgraded to TeX version 3).
VorTeX needed a separate workstation to run TeX in the background; modern PCs for the home can provide more processor power (than was available to VorTeX) in a single box. This fact has been recognised by Blue Sky Research in their `Lightning Textures' (which runs on a Macintosh in a somewhat similar way) and by TCI Software Research in `Scientific Word' (see commercial vendors), and is also the basis of many of the other environments mentioned in `editors and shells'.