Prior to 1992, "Virtual Reality" was equated with head-mounted displays. In 1991, Tom DeFanti and Dan Sandin decided to take a different approach to VR, to try to overcome some of the problems of the current technology. HMDs suffered from a number of deficiencies - most are/were rather low resolution, they are heavy and encumbering, and they isolate the user. These were serious obstacles to using for real-world applications, such as scientific visualization and engineering design. The BOOM was one alternative to typical HMDs which addressed these problems - it provided a high-resolution, high quality, less encumbering display, although it was still a single user system. Tom and Dan's approach, as implemented by EVL students and associates (Carolina Cruz-Neira, Greg Dawe, Sumit Das, Gary Lindahl, and others), made use of large-scale video projection technology, to (almost) completely remove the display from the user.