Click here to close now.



Welcome!

Linux Containers Authors: Liz McMillan, Jnan Dash, Pat Romanski, XebiaLabs Blog, Elizabeth White

Related Topics: Linux Containers

Linux Containers: Article

Version Control with Subversion

A new source control system

Recently I had the opportunity to talk with the authors of Version Control with Subversion. In this interview, they discuss what Subversion is, migrating to Subversion, and, of course, music.

What is Subversion?
Subversion is an open source version control system. It was designed to be a compelling replacement for CVS - preserving the basic workflow and user experience of that system, but providing significant improvements over CVS's model (and its implementation).

Who hosts it and what license is it distributed under? Is the license OSI approved?
Subversion is hosted by CollabNet (www.collab.net), which also funds large parts of Subversion's development. The project calls Tigris.org - an online open source collaborative software development community - its home. Subversion is developed under CollabNet's license, which is a modified version of the Apache license (and fully compliant with the Debian Free Software Guidelines).

Are any large projects using Subversion now?
Absolutely. Subversion is currently being used by many large development teams, both open source and commercial. Some examples of large open source projects using Subversion include the folks at Samba, Zope, and Xiph. Notably, the Apache Software Foundation started using Subversion in early 2003, and started migrating projects to Subversion in earnest when Subversion reached 1.0 last February. Both Apache Geronimo and Apache SpamAssassin are using Subversion, and Apache HTTP Server is preparing to convert any day now.

What was wrong with CVS? Why was a new source control system needed?
CVS works just fine for file-based version control (as does RCS, the system atop which CVS is constructed). As it turns out, most projects typically involve more than one file, and that's when you start noticing creaks in the floors and cracks in the walls. CVS does not provide atomicity for changes across multiple files - does not, in fact, even have a notion of such a change "set." CVS does not do version changes to directory structure, such as file and subdirectory additions or removals, or items that are renamed. It's extremely inefficient in its handling of "binary" (nontextual) files. It was never designed with networks in mind; that support was entirely an afterthought.

Fixing these problems within the constraints of the basic CVS architecture was already a nonviable solution. But when you then examine the state of CVS's source code and lack of a modular, extensible design, you come away without a shadow of doubt - it was time to begin anew.

What are some of the cool new features of Subversion?
Besides fixing most of the major problems found in CVS, Subversion has additional perks. For example, the file and directories you keep under version control can have property lists - arbitrary name/value pairs - attached to them. Subversion itself uses these lists to track stuff like the MIME type, preferred line-ending style, keyword expansion setting, executability, etc. But users can set their own properties willy-nilly, and use them for whatever they would like. The properties themselves are versioned, too.

Another neat feature involves Subversion's network connectivity. Since one of the available server options is an Apache WebDAV module, you have at your fingers all the functionality and extensibility that Apache offers, plus a fair degree of WebDAV interoperability, all for free. This means you can refer directly to a Subversion repository URL when trying to get your grandmother to view the latest version of something you keep under version control, and Apache will just serve up that document like any other Web resource.

Readers should check out the Subversion Web site (http://subversion.tigris.org) for news about the latest and greatest coolness flowing from that community.

What steps should I take to migrate from CVS to Subversion?
Perhaps the biggest decision involved in a migration like this is what to do with all the versioned data you currently have stored in CVS repositories. For some folks, the answer is to just leave that data in CVS, take a "top-skim" of the latest versions of all the files in that repository, and import them into a new Subversion repository. But for those who desire a full migration of their CVS history, the cvs2svn tool (http://cvs2svn.tigris.org/) is the way to go.

Along the way you'll hit other decision-making points (a beautiful side effect of Subversion's modular design). For example, you'll have to choose between a pair of back-end storage mechanisms and decide which of a handful of network access routes you'd like to use with your repository.

Of course, you'll need a copy of Version Control with Subversion by your side! There is a section entitled "How to Read This Book" in the preface, which is perhaps the best launching point for the various audiences of the book, as well as a quick-start guide at the end of Chapter 1 aimed at helping folks get set up with enough of Subversion to start experimenting with it.

So you three helped write Subversion? Why did you get involved?
Ben: In 2000, I was still working as a Unix sysadmin, pining for a chance to code again. My buddy Karl Fogel and I had started writing some free software in our spare time, but then he got the call from CollabNet. Karl wasn't willing to move to San Francisco, so he got permission to pull together a Chicago-area team. Getting paid to write open source software (with your friends) is an almost unbelievable dream come true, so I jumped at the opportunity. Karl and I still joke that we originally thought it would take six months - not four years - to finish a 1.0 product!

Fitz: Back in 2000, Karl Fogel called me up to tell me that Brian Behlendorf had hired him at CollabNet to start work on the successor to CVS. I was very excited about the idea of Subversion (which was actually called "Inversion" back then) and started following Subversion's development and helped out here and there as time permitted. Eventually, I joined CollabNet full-time where I work with Karl, Mike, and Ben on Subversion and other various mind-control, um, I mean version-control related projects. I would like to state for the record that I do not and have never played the banjo.

Mike: Ben made me do it! Seriously, working on Subversion afforded me the opportunity to help design and implement a piece of software that promised to alleviate frustrations I was running into daily using CVS and Visual Source Safe. As my first foray into the open source culture, it gave me a chance to experience firsthand what all the buzz was about. When Ben and Karl called me up to say that they were now a year into their six-month project and needed a hand, I went to work for CollabNet.

In your office, musical instruments outnumber computers two-to-one. Are you really programmers?
No, we're musicians.

Although we're programmers by day, we've all got musical interests to some degree or other.

Fitz: Ben is an amazing musician who plays piano, guitar, and banjo, not to mention the fact that he's quite the barbershop singer too. When he's not programming, writing books, answering e-mail, or helping out Subversion users on IRC, Ben composes musicals and does sound design for theater with his collaborator, Andre Pluess. Quite frankly, I don't think he sleeps. Much to Ben's chagrin, floating around in my head are a handful of songs that he and Andre have written.

Ben: Mike is the "rocker" in our office. He's got a sweet PRS electric at home, but that doesn't prevent him from playing the same songs and progressive-rock licks on his acoustic guitar at the office. Mike plays in a very talented, very tight band called Autumn War. But he also writes and records a lot of his own thoughtful songs in his home studio. Call his cellphone sometime and listen to the outgoing message; it's hilarious. Though Mike's incessant desk drumming sometimes makes Fitz want to jump out the window.

Mike: Fitz grew up in the deep south. So while he claims the high tenor line during office barbershop quartet time (between morning snack and recess), his blues guitar licks are low-down, gritty goodness. In addition, he's the office DJ. He's got more muscle in his "iPod thumb" than the average hacker has on his whole body, and he has a truckload of diverse music to boot.

About Ben Collins-Sussman
Ben Collins-Sussman has been a sysadmin and programmer for 10 years, and is one of the original designers and authors of Subversion. He currently works for CollabNet as a Subversion developer and community leader. When away from his computer, he moonlights as a musical theater composer at theaters around the city of Chicago. He lives with his lovely wife, three cats, and a house full of computer and music gizmos.

About Brian W. Fitzpatrick
Brian W. Fitzpatrick is a member of the Apache Software Foundation and currently works for CollabNet. He has been involved with Subversion in one way or another since its inception in early 2000. Originally from New Orleans, Brian moved to Chicago to attend Loyola University where he received a degree in Latin and Greek.

About C. Michael Pilato
C. Michael Pilato (Mike) is a core Subversion developer, and a leader in the Subversion community. He is currently employed by CollabNet, where he spends his days (and many nights) improving Subversion and other tools with which it integrates. A husband and father, this North Carolina native also enjoys composing and performing music, freelance graphic design work, hiking, and spending quality time with his family. Mike has a degree in computer science and mathematics from the University of North Carolina at Charlotte.

More Stories By Kevin Bedell

Kevin Bedell, one of the founding editors of Linux.SYS-CON.com, writes and speaks frequently on Linux and open source. He is the director of consulting and training for Black Duck Software.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management...
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, will provide an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profes...
SYS-CON Events announced today that VAI, a leading ERP software provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. VAI (Vormittag Associates, Inc.) is a leading independent mid-market ERP software developer renowned for its flexible solutions and ability to automate critical business functions for the distribution, manufacturing, specialty retail and service sectors. An IBM Premier Business Part...
SYS-CON Events announced today that Alert Logic, Inc., the leading provider of Security-as-a-Service solutions for the cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Alert Logic, Inc., provides Security-as-a-Service for on-premises, cloud, and hybrid infrastructures, delivering deep security insight and continuous protection for customers at a lower cost than traditional security solutions. Ful...
Fortunately, meaningful and tangible business cases for IoT are plentiful in a broad array of industries and vertical markets. These range from simple warranty cost reduction for capital intensive assets, to minimizing downtime for vital business tools, to creating feedback loops improving product design, to improving and enhancing enterprise customer experiences. All of these business cases, which will be briefly explored in this session, hinge on cost effectively extracting relevant data from ...
With the Apple Watch making its way onto wrists all over the world, it’s only a matter of time before it becomes a staple in the workplace. In fact, Forrester reported that 68 percent of technology and business decision-makers characterize wearables as a top priority for 2015. Recognizing their business value early on, FinancialForce.com was the first to bring ERP to wearables, helping streamline communication across front and back office functions. In his session at @ThingsExpo, Kevin Roberts...
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 ad...
With an estimated 50 billion devices connected to the Internet by 2020, several industries will begin to expand their capabilities for retaining end point data at the edge to better utilize the range of data types and sheer volume of M2M data generated by the Internet of Things. In his session at @ThingsExpo, Don DeLoach, CEO and President of Infobright, will discuss the infrastructures businesses will need to implement to handle this explosion of data by providing specific use cases for filte...
As enterprises work to take advantage of Big Data technologies, they frequently become distracted by product-level decisions. In most new Big Data builds this approach is completely counter-productive: it presupposes tools that may not be a fit for development teams, forces IT to take on the burden of evaluating and maintaining unfamiliar technology, and represents a major up-front expense. In his session at @BigDataExpo at @ThingsExpo, Andrew Warfield, CTO and Co-Founder of Coho Data, will dis...
SYS-CON Events announced today that Fusion, a leading provider of cloud services, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Fusion, a leading provider of integrated cloud solutions to small, medium and large businesses, is the industry's single source for the cloud. Fusion's advanced, proprietary cloud service platform enables the integration of leading edge solutions in the cloud, including clou...
Most people haven’t heard the word, “gamification,” even though they probably, and perhaps unwittingly, participate in it every day. Gamification is “the process of adding games or game-like elements to something (as a task) so as to encourage participation.” Further, gamification is about bringing game mechanics – rules, constructs, processes, and methods – into the real world in an effort to engage people. In his session at @ThingsExpo, Robert Endo, owner and engagement manager of Intrepid D...
Eighty percent of a data scientist’s time is spent gathering and cleaning up data, and 80% of all data is unstructured and almost never analyzed. Cognitive computing, in combination with Big Data, is changing the equation by creating data reservoirs and using natural language processing to enable analysis of unstructured data sources. This is impacting every aspect of the analytics profession from how data is mined (and by whom) to how it is delivered. This is not some futuristic vision: it's ha...
WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
Learn how IoT, cloud, social networks and last but not least, humans, can be integrated into a seamless integration of cooperative organisms both cybernetic and biological. This has been enabled by recent advances in IoT device capabilities, messaging frameworks, presence and collaboration services, where devices can share information and make independent and human assisted decisions based upon social status from other entities. In his session at @ThingsExpo, Michael Heydt, founder of Seamless...
The IoT's basic concept of collecting data from as many sources possible to drive better decision making, create process innovation and realize additional revenue has been in use at large enterprises with deep pockets for decades. So what has changed? In his session at @ThingsExpo, Prasanna Sivaramakrishnan, Solutions Architect at Red Hat, discussed the impact commodity hardware, ubiquitous connectivity, and innovations in open source software are having on the connected universe of people, thi...
WebRTC: together these advances have created a perfect storm of technologies that are disrupting and transforming classic communications models and ecosystems. In his session at WebRTC Summit, Cary Bran, VP of Innovation and New Ventures at Plantronics and PLT Labs, provided an overview of this technological shift, including associated business and consumer communications impacts, and opportunities it may enable, complement or entirely transform.
There are so many tools and techniques for data analytics that even for a data scientist the choices, possible systems, and even the types of data can be daunting. In his session at @ThingsExpo, Chris Harrold, Global CTO for Big Data Solutions for EMC Corporation, showed how to perform a simple, but meaningful analysis of social sentiment data using freely available tools that take only minutes to download and install. Participants received the download information, scripts, and complete end-t...
For manufacturers, the Internet of Things (IoT) represents a jumping-off point for innovation, jobs, and revenue creation. But to adequately seize the opportunity, manufacturers must design devices that are interconnected, can continually sense their environment and process huge amounts of data. As a first step, manufacturers must embrace a new product development ecosystem in order to support these products.
Manufacturing connected IoT versions of traditional products requires more than multiple deep technology skills. It also requires a shift in mindset, to realize that connected, sensor-enabled “things” act more like services than what we usually think of as products. In his session at @ThingsExpo, David Friedman, CEO and co-founder of Ayla Networks, discussed how when sensors start generating detailed real-world data about products and how they’re being used, smart manufacturers can use the dat...
When it comes to IoT in the enterprise, namely the commercial building and hospitality markets, a benefit not getting the attention it deserves is energy efficiency, and IoT’s direct impact on a cleaner, greener environment when installed in smart buildings. Until now clean technology was offered piecemeal and led with point solutions that require significant systems integration to orchestrate and deploy. There didn't exist a 'top down' approach that can manage and monitor the way a Smart Buildi...