The present invention provides a system and apparatus for efficient and reliable, control and distribution of data files or portions of files, applications, or other data objects in large-scale distributed networks. A unique content-management front-end provides efficient controls for triggering distribution of digitized data content to selected groups of a large number of remote computer servers. Transport-layer protocols interact with distribution controllers to automatically determine an optimized tree-like distribution sequence to group leaders selected by network devices at each remote site. Reliable store-and-forward transfer to clusters is accomplished using a unicast protocol in the ordered tree sequence. Once command messages and content arrive at all participating group leaders, local hybrid multicast protocols efficiently and reliably distribute them to the back-end nodes for interpretation and execution. Positive acknowledgement is then sent back to the content manager from each group leader, and the updated content in each remote device autonomously goes 'live' when the content change is locally completed.

Method and apparatus for reliable and scalable distribution of data files in distributed networks

An execution architecture, a development architecture and an operations architecture for a netcentric computing system. The execution architecture contains common, run-time services required when an application executes in the netcentric computing system. The development architecture is the production environment for one or several systems development projects as well as for maintenance efforts. The purpose of the development environment is to support the tasks involved in the analysis, design, construction, and maintenance of business systems, as well as the associated management processes. It is important to note that the environment should adequately support all the development tasks, not just the code/compile/test/debug cycle. The operations architecture is a combination of tools and support services required to keep a production system up and running efficiently.

Architectures for netcentric computing systems

A method for upgrading ( 31 - b of FIG. 1 ) a software application ( 35 - b ) from a prior version to a subsequent version while preserving user modifications to the prior application. The method includes comparing differences between the two versions of the software applications. This is followed by enumerating the differences between the two versions of the software applications; and determining which differences between the two versions of the software are conflicting and which are compatible. The compatible changes are made ( 7 ). Also disclosed is an article of manufacture containing computer readable program code for carrying out the above process, and a program storage device carrying the code.

Method and apparatus for upgrading a software application in the presence of user modifications

An important problem in program development and maintenance is version con- trol, i.e., the task of keeping a software system consisting of many versions and configurations well organized. The Revision Control System (RCS) is a software tool that assists with that task. RCS manages revisions of text documents, in particular source programs, documentation, and test data. It automates the storing, retrieval, log- ging and identification of revisions, and it provides selection mechanisms for composing configurations. This paper introduces basic version control concepts and discusses the practice of version control using RCS. For conserving space, RCS stores deltas, i.e., differences between successive revisions. Several delta storage methods are discussed. Usage statistics show that RCS's delta storage method is space and time efficient. The paper concludes with a detailed survey of version control tools.

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RCS—a system for version control

The invention provides systems and methods for continuous back up of data stored on a computer network. To this end the systems of the invention include a synchronization process that replicates selected source data files data stored on the network and to create a corresponding set of replicated data files, called the target data files, that are stored on a back up server. This synchronization process builds a baseline data structure of target data files. In parallel to this synchronization process, the system includes a dynamic replication process that includes a plurality of agents, each of which monitors a portion of the source data files to detect and capture, at the byte-level, changes to the source data files. Each agent may record the changes to a respective journal file, and as the dynamic replication process detects that the journal files contain data, the journal files are transferred or copied to the back up server so that the captured changes can be written to the appropriate ones of the target data files.

Systems and methods for backing up data files

A data processing system and method for controlling versions of data, features a processor, a storage device for storing versions of objects, and an object version selector for providing the processor with access only to specific versions of target data objects as determined by a set of selection rules. The selection rules are evaluated for an object when that object is accessed by the processor. The version selector includes a means for viewing the selected versions of the target objects as a transparent file system having directories, files, and links. The version selector applies the existing version selection rules to newly created objects, and can also store the identity of a selected object version in a cache memory. The version selection rules include a rule for selecting that version of an object that was the most recent version of that object at a specific time in the past, and a rule for selecting that version of an object that was the most recent version of that object at the specific time that a process requiring that object began. The time that the process began is adjusted to compensate for time skew among the storage devices storing the required objects. The process includes a system build.

Dynamic rule-based version control system

A support system for Computer-Aided Software Engineer (CASE) applications provides configuration management and features such as transparent retrieval of named versions of program sequences on a line by line basis as well as task monitoring and reporting. A modification record is maintained for all changes to the modules in the system build library by version numbers. Any version of a module can be obtained on a line by line basis as well as several different versions simultaneously thus supporting multiple concurrent system work on different versions by multiple users. Module monitoring is provided whereby if a module is modified when it is being monitored, all persons who might be affected thereby are notified. Task monitoring also provides notification and monitoring of tasks being accomplished as well as "blueprints" to follow in the future for the accomplishment of the same or similar tasks.

Computer device for aiding in the development of software system

A data processing system and method features an object selector including an auditor for recording, as an audit record, which versions of objects are accessed by a processor during a data processing process. Each derived object is associated with an audit record. A system build process starts the auditor prior to executing commands which produce derived objects, and stops the auditor when those commands are completed. The process also includes any arbitrary sequence of commands. An audit cache memory stores the most recent audit entries made by the auditor while producing an audit record. A linker is also provided for linking a common identifying label to each object version whose identity is recorded as an entry in an audit record associated with the identifying label. An audit record comparator is provided for determining the difference between source object versions used in building two or more derived object versions.

Dynamic software version auditor which monitors a process to provide a list of objects that are accessed

A data processing system and method for controlling files at a local development site within a geographically distributed multisite software development project includes a storage device, a processor, a mastership enforcer and an exchanger. The storage device stores a local replica including a plurality of files. Each file comprises a plurality of branches, and each branch comprises a plurality of versions of the file. The processor executes instructions, and retrieves and stores versions of the files in the storage device. The mastership enforcer provides the processor with the exclusive capability to modify specific branches by adding new versions of target files as determined by multisite mastership rules. The processor can create new versions of the target files, which are stored in the local replica within the storage device. The exchanger periodically updates the local replica by exporting the new versions of the target files to remote replicas at geographically remote development sites and importing additional new versions of the files from remote replicas. Thus, different branches of files, which are stored in multiple replicas geographically distributed at various development sites, can be modified concurrently and the replicas are updated with each others modifications periodically, without losing modifications or allowing inconsistent modifications among the replicas.

Version control system for geographically distributed software development

Computer-Aided Software Engineering environments are becoming essential for complex software projects, just as CAD systems have become essential for complex hardware projects. DSEE, the DOMAIN Software Engineering Environment, is a distributed, production quality, software development environment that runs on Apollo workstations. DSEE provides source code control, configuration management, release control, advice management, task management, and user-defined dependency tracking with automatic notification.DSEE incorporates some of the best ideas from existing systems. This paper describes DSEE, contrasts it other systems, and discusses some of the technical issues involved in the construction of a highly-reliable, safe, efficient, and distributed development environment.

David B. Leblang

Papers

Dynamic rule-based version control system

Computer device for aiding in the development of software system

Dynamic software version auditor which monitors a process to provide a list of objects that are accessed

Version control system for geographically distributed software development

Computer-Aided Software Engineering in a distributed workstation environment