We describe methods to produce software and multimedia documents that are self-versioning---they efficiently capture changes as the document is modified, providing access to every version with extremely fine granularity. The approach uses an object-based spatial indexing scheme that combines fast access with very low storage overhead. Multiple tools can extract change reports from these documents without requiring their queries to be synchronized. We describe and evaluate a working implementation of these ideas, suitable for use in software development environments, multimedia authoring systems, and non-traditional databases. 1.

We present and algorithm for modifying delta compressed files so that the compressed versions may be reconstructed without requiring additional memory or storage space. This allows network clients with limited resources to efficiently update software by downloading delta compressed versions over a network. Delta compression for binary files, compactly encoding a version of data with only the changed bytes from a previous version, may be used to efficiently distribute software over low bandwidth channels, such as the Internet. Traditional methods of rebuilding these delta files require memory or storage space on the target machine for both the old and new version of the file to be reconstructed. With the advent of network computing and Internet set-top boxes, many of these network attached target machines have limited additional scratch space in memory or storage. We provide an algorithm for modifying a delta compressed version file so that it may rebuild the new file version in the spa...

this paper, we introduce a more advanced merging system that is characterized by three aspects: (1) it compares programs in a way that corresponds more closely to the syntactic structure of the programs; (2) it utilizes advanced display hardware to highlight the differences in colors; (3) it is built on top of an existing popular editor so that the merging system can benefit the most people while requiring the least amount of learning effort. Figure 1 depicts a sample editing session. Suppose that a user wants to merge two versions of a program A and B. A comparison utility compares the two versions and produces an intermediate merged file. The merging editor displays the intermediate merged file as shown in Figure 1 (c). Since it is not possible to display colors on the printed document, we use single and double boxes to indicate that the differences are highlighted in colors. Texts in the single-boxes are highlighted in one color (e.g. green) on the display, which indicates that the texts appear only in the first version. Similarly, texts in the double-boxes are highlighted in a different color (e.g. yellow) to indicate that the texts appear only in the second version. Texts not enclosed in any boxes, which are displayed in the normal color (e.g. black), are the common part of both versions. (We will discuss Figure 1 (d) in a later section.) One of the fundamental components of a merging system is a utility that can identify the differences between two programs. The differences may be captured by comparing the programs line by line, resulting in what we call textual difference. Textual difference is a crude comparison; a user needs to spend more time in understanding the differences and performing the merging task. On the other hand, since there is a rigid syntactic ...

Software Configuration Management (SCM) is an important discipline in professional software development and maintenance. The importance of SCM has increased as programs have become larger and more complex and mission/life-critical. This paper discusses the evolution of SCM technology from the early days of software development to present and the impact university and industrial research has had along the way. It also includes a survey of the industrial state-of-the-practice and research directions.

Abstract—In-place reconstruction of differenced data allows information on devices with limited storage capacity to be updated efficiently over low-bandwidth channels. Differencing encodes a version of data compactly as a set of changes from a previous version. Transmitting updates to data as a version difference saves both time and bandwidth. In-place reconstruction rebuilds the new version of the data in the storage or memory the current version occupies—no scratch space is needed for a second version. By combining these technologies, we support highly mobile applications on space-constrained hardware. We present an algorithm that modifies a differentially encoded version to be in-place reconstructible. The algorithm trades a small amount of compression to achieve this property. Our treatment includes experimental results that show our implementation to be efficient in space and time and verify that compression losses are small. Also, we give results on the computational complexity of performing this modification while minimizing lost compression.

Managing software products during software development is essential. A model is needed to model products and facilitates product management. Important product management functions include: 1) version control, 2) configuration management, 3) product consistency management, 4) reference completeness management, and 5) product reuse support. This paper proposes a product model to facilitate the functions above. Since product relationships play important roles in product management, the proposed model especially emphasizes them.

This paper discusses differential editors in general and gives two important examples of the paradigm. One example is an editor augmented for bank statement reconciliation. The other is a program text editor augmented to handle multiple versions of source text, using preprocessor control lines to delimit individual versions.

Software Configuration Management (SCM) is an important discipline in professional software development and maintenance. The importance of SCM has increased as programs have become larger, more long lasting, and more mission and life critical. This article discusses the evolution