PIX, the latest NeWS

The NeWS window server from Sun Microsystems is the addition of quasiparallelism to PostScript. NeWS uses this parallelism to deal with the inherent concurrency of human/computer interactions. NeWS provides multiple, lightweight processes to deal with this parallelism; as a result, user interfaces are demonstrably easier to implement using NeWS than using other window servers. The pseudoconcurrency of NeWS naturally suggests that it might be an excellent candidate for execution on a true parallel processor. The goal of the PIX (parallel interactive executive) project was to produce a version of NeWS that runs on parallel processors, and to fix some problems with NeWS. In addition, execution NeWS on a parallel processor does more than just provide execution speed advantages, it begins to redefine the role of server-based user interfaces in modern computer systems. PIX extensions of NeWS include: preemptive process scheduling; Linda operators are used for safe interprocess communication; and a decentralized event mechanism. PIX also allows for separately compiled primitives.<>