Subversion SCM Tool Becomes More Robust with Version 1.5

June 24, 2008 Alex Woodie

It will be easier for software development teams that use the Subversion open source software configuration management (SCM) product to keep track of their projects with Subversion 1.5, which was released last week. CollabNet, the online community that backs development of Subversion, says new features like merge tracking, interactive conflict resolution, and improved read performance make Subversion 1.5 the most significant release in the last four years.

Subversion began in 2000 as a project to develop an open source version control and SCM tool to speed development and reduce cost and complexity for distributed groups of programmers. CollabNet, the company behind Subversion, released version 1.0 in 2004, and since then, the software has been used by an estimated 3.2 million developers. About 2 million developers use the free open-source version of the software that’s available at subversion.tigris.org, while about 1.5 million use one of three for-fee products or services from CollabNet, all of which use Subversion for the core SCM capabilities.

Work on a version of Subversion for the i OS (formerly i5/OS and OS/400) platform began in 2004. The project resulted from the collaboration between CollabNet and SoftLanding Systems, which was one of the dominant providers of SCM and change management tools for the platform at the time. The port wascompleted in 2005, when SoftLanding rolled out two products, the free Subversion for OS/400 product and a for-fee version that included technical support called TurnOver SVN. When SoftLanding was acquired by CICS specialist Unicom Systems the following year, the two SoftLanding developers who worked on the Subversion project, Mark Phippard and Paul Burba, took jobs at CollabNet.

Fast forward to 2008, and Subversion is looking like the solid front-runner in enterprise SCM tools. CollabNet is highly touting a recent Forrester report that ranked Subversion higher than all other standalone SCM products, including Rational Clearcase from IBM.

With version 1.5, the performance and scalability of Subversion improves. The most requested new feature was merge tracking, which should provide more automated and efficient management of branches of code among geographically separated teams of developers. The new software provides interactive conflict resolution, which enables users to resolve issues during the merge process. Subversion 1.5 keeps a complete history of merges, as well as annotated logs that allow users to query for available changes on different lines of development. Backing out changes to code is also easier thanks to the merge tracking functionality.

Other new features include “sparse” checkouts to enable users to check out only a portion of a source tree to reduce the total footprint on their individual workstations; a new repository “sharding” and partitioning feature that makes distribution of repository storage across file systems more efficient; and a new proxying system for spreading read-load across multiple repository servers for improved performance.

“Measuring by new features alone, Subversion 1.5 is our biggest release since version 1.0 became available in February 2004,” said Karl Fogel, president of the non-profit Subversion Corporation. “In Subversion 1.5, we made a conscious effort to integrate ideas from both individual and corporate users. That process worked quite well, and we will probably continue to use it for future development.”

Subversion 1.5 runs on and supports i5/OS, Unix, Linux, Windows, BeOS, OS/2, and MacOS X. The software can be downloaded at subversion.tigris.org, or obtained through the CollabNet Subversion, CollabNet/SourceForge Enterprise Edition, or CollabNet CUBiT offerings from CollabNet.