A critical evaluation of PEX
Hyunchan Sung, Gene Rogers, William J. Kubitz · IEEE Computer Graphics and Applications · 1990
PEX, the PHIGS extension to the X Window System, is evaluated in the context of assumptions inherent in the PHIGS output, modeling, input, user interface, and system environment models. Problems not previously discussed arise when examining PEX this way. The problems not only pertain to the implementation of PEX, but also to implementing a 3-D library in a distributed windowing system in general. The University of Illinois PEX implementation serves as a reference to discuss the solutions proposed.>