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Version Control Systems
In software engineering, version control (also known as revision control, source control, or source code management) is a class of systems responsible for managing changes to computer programs, documents, large web sites, or other collections of information. Version control is a component of software configuration management. Changes are usually identified by a number or letter code, termed the "revision number", "revision level", or simply "revision". For example, an initial set of files is "revision 1". When the first change is made, the resulting set is "revision 2", and so on. Each revision is associated with a timestamp and the person making the change. Revisions can be compared, restored, and, with some types of files, merged. The need for a logical way to organize and control revisions has existed for almost as long as writing has existed, but revision control became much more important, and complicated, when the era of computing began. The numbering of book editions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Engineering
Software engineering is a systematic engineering approach to software development. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term '' programmer'' is sometimes used as a synonym, but may also lack connotations of engineering education or skills. Engineering techniques are used to inform the software development process which involves the definition, implementation, assessment, measurement, management, change, and improvement of the software life cycle process itself. It heavily uses software configuration management which is about systematically controlling changes to the configuration, and maintaining the integrity and traceability of the configuration and code throughout the system life cycle. Modern processes use software versioning. History Beginning in the 1960s, software engineering was seen as its own type of engineering. Additionally, the development of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Code
In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source code. The source code is often transformed by an assembler or compiler into binary machine code that can be executed by the computer. The machine code is then available for execution at a later time. Most application software is distributed in a form that includes only executable files. If the source code were included it would be useful to a user, programmer or a system administrator, any of whom might wish to study or modify the program. Alternatively, depending on the technology being used, source code may be interpreted and executed directly. Definitions Richard Stallman's definition, formulated in his 1989 seminal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
File Locking
File locking is a mechanism that restricts access to a computer file, or to a region of a file, by allowing only one user or process to modify or delete it at a specific time and to prevent reading of the file while it's being modified or deleted. Systems implement locking to prevent the classic ''interceding update'' scenario, which is a typical example of a race condition, by enforcing the serialization of update processes to any given file. The following example illustrates the interceding update problem: # Process A reads a customer record from a file containing account information, including the customer's account balance and phone number. # Process B now reads the same record from the same file, so it has its own copy. # Process A changes the account balance in its copy of the customer record and writes the record back to the file. # Process B, which still has the original ''stale'' value for the account balance in its copy of the customer record, updates the account bala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Revision Control
In software development, distributed version control (also known as distributed revision control) is a form of version control in which the complete codebase, including its full history, is mirrored on every developer's computer. Compared to centralized version control, this enables automatic management branching and merging, speeds up most operations (except pushing and pulling), improves the ability to work offline, and does not rely on a single location for backups. Git, the world's most popular version control system, is a distributed version control system. In 2010, software development author Joel Spolsky described distributed version control systems as "possibly the biggest advance in software development technology in the astten years". Distributed vs. centralized Distributed version control systems (DVCS) use a peer-to-peer approach to version control, as opposed to the client–server approach of centralized systems. Distributed revision control synchronizes repositor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apache Subversion
Apache Subversion (often abbreviated SVN, after its command name ''svn'') is a software versioning and revision control system distributed as open source under the Apache License. Software developers use Subversion to maintain current and historical versions of files such as source code, web pages, and documentation. Its goal is to be a mostly compatible successor to the widely used Concurrent Versions System (CVS). The open source community has used Subversion widely: for example, in projects such as Apache Software Foundation, Free Pascal, FreeBSD, SourceForge, and from 2006 to 2019, GCC. CodePlex was previously a common host for Subversion repositories. Subversion was created by CollabNet Inc. in 2000, and is now a top-level Apache project being built and used by a global community of contributors. History CollabNet founded the Subversion project in 2000 as an effort to write an open-source version-control system which operated much like CVS but which fixed the bugs a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrent Versions System
Concurrent Versions System (CVS, also known as the Concurrent Versioning System) is a revision control system originally developed by Dick Grune in July 1986. CVS operates as a front end to RCS, an earlier system which operates on single files. It expands upon RCS by adding support for repository-level change tracking, and a client-server model. Released under the terms of the GNU General Public License, CVS is free software. Design CVS operates as a front end to Revision Control System (RCS), an older version control system that manages individual files but not whole projects. It expands upon RCS by adding support for repository-level change tracking, and a client-server model. Files are tracked using the same history format as in RCS, with a hidden directory containing a corresponding history file for each file in the repository. CVS uses delta compression for efficient storage of different versions of the same file. This works well with large text files with few cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revision Control System
Revision Control System (RCS) is an early implementation of a version control system (VCS). It is a set of UNIX commands that allow multiple users to develop and maintain program code or documents. With RCS, users can make their own revisions of a document, commit changes, and merge them. RCS was originally developed for programs but is also useful for text documents or configuration files that are frequently revised. History Development RCS was first released in 1982 by Walter F. Tichy at Purdue University. It was an alternative tool to the then-popular Source Code Control System (SCCS) which was nearly the first version control software tool (developed in 1972 by early Unix developers). RCS is currently maintained by the GNU Project. An innovation in RCS is the adoption of ''reverse deltas''. Instead of storing every revision in a file like SCCS does with interleaved deltas, RCS stores a set of edit instructions to go back to an earlier version of the file. Tichy claims ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Code Control System
Source Code Control System (SCCS) is a version control system designed to track changes in source code and other text files during the development of a piece of software. This allows the user to retrieve any of the previous versions of the original source code and the changes which are stored. It was originally developed at Bell Labs beginning in late 1972 by Marc Rochkind for an IBM System/370 computer running OS/360. A characteristic feature of SCCS is the ''sccsid'' string that is embedded into source code, and automatically updated by SCCS for each revision. This example illustrates its use in the C programming language: static char sccsid[] = "@(#)ls.c 8.1 (Berkeley) 6/11/93"; This String (computer science), string contains the file name, date, and can also contain a comment. After compilation, the string can be found in binary and object files by looking for the pattern @(#) and can be used to determine which source code files were used during compilation. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Support Programs For OS/360 And Successors
This article discusses support programs included in or available for OS/360 and successors. IBM categorizes some of these programs as utilities and others as service aids; the boundaries are not always consistent or obvious. Many, but not all, of these programs match the types in utility software. The following lists describe programs associated with OS/360 and successors. No DOS, TPF or VM utilities are included. History/Common JCL Many of these programs were designed by IBM users, through the group SHARE, and then modified or extended by IBM from versions originally written by a user. These programs are usually invoked via Job Control Language (JCL). They tend to use common JCL DD identifiers (in the OS, now z/OS operating systems) for their data sets: Dataset utilities IDCAMS IDCAMS ("Access Method Services") generates and modifies Virtual Storage Access Method (VSAM) and Non-VSAM datasets. IDCAMS was introduced along with VSAM in OS/VS; the "Access Method" referenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Configuration Files
In computing, configuration files (commonly known simply as config files) are files used to configure the parameters and initial settings for some computer programs. They are used for user applications, server processes and operating system settings. Some applications provide tools to create, modify, and verify the syntax of their configuration files; these sometimes have graphical interfaces. For other programs, system administrators may be expected to create and modify files by hand using a text editor, which is possible because many are human-editable plain text files. For server processes and operating-system settings, there is often no standard tool, but operating systems may provide their own graphical interfaces such as YaST or debconf. Some computer programs only read their configuration files at startup. Others periodically check the configuration files for changes. Users can instruct some programs to re-read the configuration files and apply the changes to the curr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trunk (software)
Branching, in version control and software configuration management, is the duplication of an object under version control (such as a source code file or a directory tree). Each object can thereafter be modified separately and in parallel so that the objects become different. In this context the objects are called branches. The users of the version control system can branch any branch. Branches are also known as ''trees'', ''streams'' or ''codelines''. The originating branch is sometimes called the ''parent branch'', the ''upstream branch'' (or simply ''upstream'', especially if the branches are maintained by different organizations or individuals), or the ''backing stream''. ''Child branches'' are branches that have a parent; a branch without a parent is referred to as the trunk or the ''mainline''. The trunk is also sometimes loosely referred to as HEAD, but properly head refers not to a branch, but to the most recent commit on a given branch, and both the trunk and each named b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branching (revision Control)
Branching, in version control and software configuration management, is the duplication of an object under version control (such as a source code file or a directory tree). Each object can thereafter be modified separately and in parallel so that the objects become different. In this context the objects are called branches. The users of the version control system can branch any branch. Branches are also known as ''trees'', ''streams'' or ''codelines''. The originating branch is sometimes called the ''parent branch'', the ''upstream branch'' (or simply ''upstream'', especially if the branches are maintained by different organizations or individuals), or the ''backing stream''. ''Child branches'' are branches that have a parent; a branch without a parent is referred to as the trunk or the ''mainline''. The trunk is also sometimes loosely referred to as HEAD, but properly head refers not to a branch, but to the most recent commit on a given branch, and both the trunk and each named ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
