Portability, efficiency and ease of coding are all important considerations in choosing the programming model for a scalable parallel application. The message-passing programming model is widely used because of its portability, yet some applications are too complex to code in it while also trying to maintain a balanced computation load and avoid redundant computations. The shared-memory programming model simplifies coding, but it is not portable and often provides little control over interprocessor data transfer costs. This paper describes a new approach, called Global Arrays (GA) that combines the better features of both other models, leading to both simple coding and efficient execution. The key concept of GA is that it provides a portable interface through which each process in a MIMD parallel program can asynchronously access logical blocks of physically distributed matrices, with no need for explicit cooperation by other processes. We have implemented GA libraries on a variety of computer systems, including the Intel DELTA and Paragon, the IBM SP-1 (all message-passers), the Kendall Square KSR-2 (a nonuniform access shared-memory machine), and networks of Unix workstations. We discuss the design and implementation of these libraries, report their performance, illustrate the use of GA in the context of computational chemistry applications, and describe the use of a GA performance visualization tool.>

This paper describes a programming system called Amber that permits a single application program to use a homogeneous network of computers in a uniform way, making the network appear to the application as an integrated multiprocessor. Amber is specifically designed for high performance in the case where each node in the network is a shared-memory multiprocessor.

Priority windows are a basic tool for interactive graphics, underlying such techniques as pop-up menus and single screen viewing and control of multiple contexts. Most implementations of priority windows are raster oriented, frequently relying on special hardware capabilities such as high speed rasterops. This paper discusses an alternative approach, based on vector clipping, that works with any display device capable of drawing and erasing vectors. It has been used to implement a general purpose windowing package that supports application programs using a vector graphics model. It is device independent, running without change on a desktop computer with integral graphics and on a timesharing system with a peripheral display. In purely device independent form, windowing performance depends on host processing speed and communications bandwidth. Techniques are described for improving responsiveness by overlapping some windowing computations with the user's think time. Performance improvements based on extended device capabilities such as rectangular fill, hardware characters, and local display lists with clipping are also suggested.