The Evolution of C Programming Practices: A Study of the Unix Operating System 1973-2015

Tracking long-term progress in engineering and applied science allows us to take stock of things we have achieved, appreciate the factors that led to them, and set realistic goals for where we want to go. We formulate seven hypotheses associated with the long term evolution of C programming in the Unix operating system, and examine them by extracting, aggregating, and synthesising metrics from 66 snapshots obtained from a synthetic software configuration management repository covering a period of four decades. We found that over the years developers of the Unix operating system appear to have evolved their coding style in tandem with advancements in hardware technology, promoted modularity to tame rising complexity, adopted valuable new language features, allowed compilers to allocate registers on their behalf, and reached broad agreement regarding code formatting. The progress we have observed appears to be slowing or even reversing prompting the need for new sources of innovation to be discovered and followed

Supporting Source Code Feature Analysis Using Execution Trace Mining

Software maintenance is a significant phase of a software life-cycle. Once a system is developed the main focus shifts to maintenance to keep the system up to date. A system may be changed for various reasons such as fulfilling customer requirements, fixing bugs or optimizing existing code. Code needs to be studied and understood before any modification is done to it. Understanding code is a time intensive and often complicated part of software maintenance that is supported by documentation and various tools such as profilers, debuggers and source code analysis techniques. However, most of the tools fail to assist in locating the portions of the code that implement the functionality the software developer is focusing. Mining execution traces can help developers identify parts of the source code specific to the functionality of interest and at the same time help them understand the behaviour of the code. We propose a use-driven hybrid framework of static and dynamic analyses to mine and manage execution traces to support software developers in understanding how the system's functionality is implemented through feature analysis. We express a system's use as a set of tests. In our approach, we develop a set of uses that represents how a system is used or how a user uses some specific functionality. Each use set describes a user's interaction with the system. To manage large and complex traces we organize them by system use and segment them by user interface events. The segmented traces are also clustered based on internal and external method types. The clusters are further categorized into groups based on application programming interfaces and active clones. To further support comprehension we propose a taxonomy of metrics which are used to quantify the trace. To validate the framework we built a tool called TrAM that implements trace mining and provides visualization features. It can quantify the trace method information, mine similar code fragments called active clones, cluster methods based on types, categorise them based on groups and quantify their behavioural aspects using a set of metrics. The tool also lets the users visualize the design and implementation of a system using images, filtering, grouping, event and system use, and present them with values calculated using trace, group, clone and method metrics. We also conducted a case study on five different subject systems using the tool to determine the dynamic properties of the source code clones at runtime and answer three research questions using our findings. We compared our tool with trace mining tools and profilers in terms of features, and scenarios. Finally, we evaluated TrAM by conducting a user study on its effectiveness, usability and information management

Designing a Library of Components for Textual Scholarship

Il presente lavoro affronta e descrive temi legati all'applicazione di nuove tecnologie, di metodologie informatiche e di progettazione software volti allo sviluppo di strumenti innovativi per le Digital Humanities (DH), un’area di studio caratterizzata da una forte interdisciplinarità e da una continua evoluzione. In particolare, questo contributo definisce alcuni specifici requisiti relativi al dominio del Literary Computing e al settore del Digital Textual Scholarship. Conseguentemente, il contesto principale di elaborazione tratta documenti scritti in latino, greco e arabo, nonché testi in lingue moderne contenenti temi storici e filologici. L'attività di ricerca si concentra sulla progettazione di una libreria modulare (TSLib) in grado di operare su fonti ad elevato valore culturale, al fine di editarle, elaborarle, confrontarle, analizzarle, visualizzarle e ricercarle. La tesi si articola in cinque capitoli. Il capitolo 1 riassume il contesto del dominio applicativo e fornisce un quadro generale degli obiettivi e dei benefici della ricerca. Il capitolo 2 illustra alcuni importanti lavori e iniziative analoghe, insieme a una breve panoramica dei risultati più significativi ottenuti nel settore delle DH. Il capitolo 3 ripercorre accuratamente e motiva il processo di progettazione messo a punto. Esso inizia con la descrizione dei principi tecnici adottati e mostra come essi vengono applicati al dominio d'interesse. Il capitolo continua definendo i requisiti, l'architettura e il modello del metodo proposto. Sono così evidenziati e discussi gli aspetti concernenti i design patterns e la progettazione delle Application Programming Interfaces (APIs). La parte finale del lavoro (capitolo 4) illustra i risultati ottenuti da concreti progetti di ricerca che, da un lato, hanno contribuito alla progettazione della libreria e, dall'altro, hanno avuto modo di sfruttarne gli sviluppi. Sono stati quindi discussi diversi temi: (a) l'acquisizione e la codifica del testo, (b) l'allineamento e la gestione delle varianti testuali, (c) le annotazioni multilivello. La tesi si conclude con alcune riflessioni e considerazioni indicando anche possibili percorsi d'indagine futuri (capitolo 5)

実世界入出力を伴うプログラムの画像表現を用いた開発支援手法

学位の種別:課程博士University of Tokyo(東京大学

Issues, opportunities and concepts in the teaching of programming to novice programmers at the University of Lincoln : three approaches.

This thesis describes three small-scale, computer-based approaches developed and used by the author in her teaching of programming concepts to novice programmers, using Pascal as a first language, within a higher education context. The first approach was the development of a piece of tutorial CAL, the second was the development of an on-line help system and the third the development of a pattern language. For the first two, the author created the product. For the pattern language, she designed the template. These three approaches are described and the results obtained outlined. The work also looks at the kind of research methodologies and tools available to the author and present a rationale for her choices of method and tools. This work also briefly reviews some learning theories that could be used to underpin the design, use and evaluation of CAL. The thesis looks at a range of topics associated with the teaching of programming and the use of CAL. It looks at issues around the psychology and human aspects of learning to program, such as confirmatory bias and vision. It looks at other research efforts aimed at developing software to support inexperienced programmers, including new programming languages specifically designed to teach programming concepts and sophisticated programming support environments. The work briefly reviews various types of CAL and their uses. It also examines some key projects in CAL development from the 1960s onwards, with particular emphasis on UK projects from the early 1970s to the late 1990s. It looks at what conclusions can be drawn from examining some of the many CAL projects in the past. Finally, the work reviews the various strands of the author's research efforts and presents a brief overview and some initial suggestions for the teaching of programming to novice programmers