We describe a package of practical tools and libraries for manipulating graphs and their drawings. Our design, which aimed at facilitating the combination of the package components with other tools, includes stream and event interfaces for graph operations, high-quality static and dynamic layout algorithms, and the ability to handle sizable graphs. We conclude with a description of the applications of this package to a variety of software engineering tools.

The Software Engineering Research department at Murray Hill writes and distributes several widely used development tools and reusable libraries that are portable across virtually all UNIX platforms. [1] To enhance reuse of these tools and libraries, we want to make them available on systems running Windows NT [2] and/or Windows 95 [3] . We did not want to support multiple versions of these libraries, and we wanted to minimize the amount of conditionally compiled code. This paper describes an effort of trying to build a UNIX interface layer on top of the Windows NT and Windows 95 operating system. The goal was to build an open environment rich enough to be both a good development environment and a suitable execution environment. This meant that the overhead needed to be small enough so that there was no incentive to program to the native operating system directly. The openness meant that the complete facilities of the native operating system were accessible through this environmen...

Although our society increasingly relies on computing systems for smooth, efficient operation; computer "errors" that interrupt our lives are commonplace. Better error and exception handling seems to be correlated with more reliable software systems[shelton00][koopman99]. Unfortunately, robust handling of exceptional conditions is a rarity in modern software systems, and there are no signs that the situation is improving. This dissertation examines the central issues surrounding the reasons why software systems are, in general, not robust, and presents methods of resolving each issue. Although it is commonly held that building robust code is too impractical, we present methods of addressing common robustness failures in a simple, generic fashion. We develop uncomplicated checking mechanisms that can be used to detect and handle exceptional conditions before they can affect process or system state (preemptive detection). This gives a software system the information it needs to gracefully recover from the exceptional condition without the need for task restarts. The perception that computing systems can be either robust or fast (but not both) is a myth perpetuated by not only a dearth of quantitative data, but also an abundance of conventional wisdom whose truth is rooted in an era before modern superscalar processors. The advanced microarchitectural features of such processors are the key to building and understanding systems that are both fast and robust. This research provides an objective, quantitative analysis of the performance cost associated with making a software system highly robust. It develops methods by which the systems studied can be made robust for less than 5% performance overhead for nearly every case, and often much less. Studies indicate that most prog...

This paper describes an effort of trying to build a UNIX interface layer on top of the Windows NT [1] and Windows 95 [2] operating system. The goal was to build an open environment rich enough to be both a good development environment and a suitable execution environment. The result of this effort is a set of libraries, headers, and utilities that we collectively refer to as UWIN. UWIN contains nearly all the X/Open Release 4 [3] headers, interfaces, and commands. An earlier paper on porting to Windows NT [4] , describes alternative porting strategies and presents some performance results for UWIN. In this paper we discuss some of the design decisions behind UWIN and some of the results so far as well as some of the remaining challenges. 1. INTRODUCTION The marketplace has dictated the need for software applications to work on a variety of operating system platforms. Yet, maintaining separate source code versions and development environments creates additional expense and requ...

This paper describes an effort of trying to build a UNIX interface layer on top of the Windows NT [1] and Windows 95 [2] operating system. The goal was to build an open environment rich enough to be both a good development environment and a suitable execution environment. The result of this effort is a set of libraries, headers, and utilities that we collectively refer to as UWIN. UWIN contains nearly all the X/Open Release 4 [3] headers, interfaces, and commands. An earlier paper on porting to Windows NT [4], describes alternative porting strategies and presents some performance results for UWIN. In this paper we discuss some of the design decisions behind UWIN and some of the results so far as well as some of the remaining challenges. 1.