IBM Rational ClearCase

With Rational ClearCase is a scalable software configuration management, which the areas versioning, parallel development, workspace management, and build and release management addressed. It provides functions needed to create, update, production ( build), distribution and reuse of all types of artifacts are helpful. ClearCase is available for Linux, Windows, Unix and mainframe computers ( z / OS) and thus enables a cross-platform application development. The optional extension MultiSite or the use of the ClearCase Remote Client ( CCRC ) parallel software development over geographically distributed environments is made possible time.

History

ClearCase was originally developed in 1990 by David Leblang and Howard Spilke, employees of Millennium Teamware and came after about one and a half years of development in 1992 as a first Atria ClearCase for Unix operating systems on the market. ( For legal reasons, had to be in the company Atria Software renamed). In ClearCase, it was after VAX CMS and Apollo DSEE already to the third SCM tool, had worked on the Leblang.

Atria Software was then bought in 1996 by Pure Software and changed its name since then as PureAtria. Later Rational Software took over the company PureAtria before Rational Software was acquired in 2003 by IBM.

Releases

Special

All versioned objects called artifacts are stored in ClearCase in a separate repository which as VOB ( Versioned Object Base ) is called. To then be able to edit certain versions of these artifacts, ClearCase has a mechanism ( in the sense of " vision " in the VOB) realized by a so-called views. These views behave on the client computer as another file system that transparently integrates into the File Manager, for example, so that access to versioned and unversioned files is done in the same way.

ClearCase stores file versions according to the so-called in-line delta storage principle. The changes between different versions of a file are stored with a special notation in the file itself. In this way, any version can be equal fast.

In addition to the integration in the file manager working with versioned files through integration into a variety of other products and development environments (Microsoft Visual Studio, Eclipse IDE, Microsoft Word, Code :: Blocks, NetBeans, ...) is facilitated. Of course, ClearCase also has integrations with other IBM Rational products such as Rational ClearQuest, Rational Rose, Rational Application Developer, the basis for the traceability of changes throughout the development process - serve - from request to the corresponding test cases.

In addition, ClearCase provides the ability to be used without installing any client side software through a browser. Based on the web technology available since version 6 is also an Eclipse -based ClearCase Remote Client ( CCRC ) are available, the scope has been expanded continuously since its introduction.

ClearCase support in principle two different ways of working, which are referred to as base ClearCase and UCM (Unified Change Management). This base ClearCase provides greater flexibility, but requires more effort for it in the implementation of the procedure. UCM that is based on base ClearCase, backed with a pre- procedure easier commissioning, but offers less flexibility.

• Integrated Software Build Management: ClearCase allowed by the integrated build tools omake and make clear the use of "derived objects". The resulting when compiling objects can be cached in the view or VOB and reused in the next build, so that the performance of a software builds can increase significantly. Also allows you to assign a Configuration Record during the build, where, for example, all files used for the build are stored with the appropriate version number.

UCM

• UCM Unified Change Management is a predefined Rational process, which generally supports the software development. The UCM Project contains several components, which can in turn comprise a plurality of files in the rule. The developer is working with UCM on their own streams. The work orders ( Activities) can span multiple files to be changed. Defined objects (such as release level ) are marked by baselines, similar to the label under ClearCase.

Multisite

The extension ClearCase MultiSite replicates the data of the ClearCase system stored in the VOBs to any number of other locations ( sites), thus facilitating the work of distributed teams to shared data.

When adding a new location initially one or more VOBs is transferred to the person or other location (s ) ( replication). During operation, then a regular only sent those data ( synchronized) that have been changed at one of the locations.

In order to control concurrent processing on a version of an artifact, leads a multi-site, the principle of Mastership. Here, the mastership of a branch version of an artifact is at a time in exactly one location. Only the site that has the Mastership can create new versions on this branch. All other sites can only read (at this time ) to this branch in the version tree. Editing the versions on other branches of the same artifact is unaffected and remains at any time. The Mastership can also be transferred to another or from one location requested (Request for Mastership ).