Development of a large graphics-based application package

Abstract

CERN, the European Laboratory for Particle Physics, is one of the largest scientific research laboratories in the world. Most of the research work carried out in the Laboratory is not only strongly dependent upon the large particle accelerators in operation, but it also relies heavily on the use of computer systems of which several hundreds, of various types, are presently installed. During the last 20 years, CERN has played a leading role as the focus for development of packages and software libraries to solve problems related to High Energy Physics (HEP). The results of the integration of resources from many different Laboratories can be expressed in several millions lines of code written at CERN during this period of time, used at CERN and distributed to collaborating Laboratories. Nowadays, this role of software developer is considered very important by the entire HEP community. This paper reports the development of a large application package. The paper is divided into two parts. Firstly, a large software package where graphics play a key role (PAW—Physics Analysis Workstation) is taken as a case study, and its origin and main characteristics are presented in detail. PAW is essentially an interactive system which includes many different software tools, strongly oriented towards data analysis and data presentation. Secondly, the criteria and rules to be obeyed for the development of a large package in the environment of a large international collaboration are outlined. Then, the development process of the package is described and some of the problems encountered and the solutions adopted are discussed.