Click here to close now.

Welcome!

Linux Authors: Roger Strukhoff, Liz McMillan, Lori MacVittie, Carmen Gonzalez, Yeshim Deniz

Related Topics: Linux

Linux: 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
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, and physical persons. In the IoT vision, every new "thing" - sensor, actuator, data source, data con...
It's time to put the "Thing" back in IoT. Whether it’s drones, robots, self-driving cars, ... There are multiple incredible examples of the power of IoT nowadays that are shadowed by announcements of yet another twist on statistics, databases, .... Sorry, I meant, Big Data(TM), tiered storage(TM), complex systems(TM), smart nations(TM), .... In his session at WebRTC Summit, Dr Alex Gouaillard, CTO and Co-Founder of Temasys, will discuss the concrete, cool, examples of IoT already happening today, and how mixing all those different sources of visual and audio input can make your life happier ...
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover how hardware commoditization, the ubiquitous nature of connectivity, and the emergence of Big Data a...
SYS-CON Events announced today the IoT Bootcamp – Jumpstart Your IoT Strategy, being held June 9–10, 2015, in conjunction with 16th Cloud Expo and Internet of @ThingsExpo at the Javits Center in New York City. This is your chance to jumpstart your IoT strategy. Combined with real-world scenarios and use cases, the IoT Bootcamp is not just based on presentations but includes hands-on demos and walkthroughs. We will introduce you to a variety of Do-It-Yourself IoT platforms including Arduino, Raspberry Pi, BeagleBone, Spark and Intel Edison. You will also get an overview of cloud technologies s...
SYS-CON Media announced today that @WebRTCSummit Blog, the largest WebRTC resource in the world, has been launched. @WebRTCSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @WebRTCSummit Blog can be bookmarked ▸ Here @WebRTCSummit conference site can be bookmarked ▸ Here
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
Avnet, Inc. has announced that it ranked No. 4 on the InformationWeek Elite 100 – a list of the top business technology innovators in the U.S. Avnet was recognized for the development of an innovative cloud-based training system that serves as the foundation for Avnet Academy – the company’s education and training organization focused on technical training around top IT vendor technologies. The development of this system allowed Avnet to quickly expand its IT-related training capabilities around the world, while creating a new service that Avnet and its IT solution providers can offer to their...
The WebRTC Summit 2015 New York, to be held June 9-11, 2015, at the Javits Center in New York, NY, announces that its Call for Papers is open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 16th International Cloud Expo, @ThingsExpo, Big Data Expo, and DevOps Summit.
Chuck Piluso will present a study of cloud adoption trends and the power and flexibility of IBM Power and Pureflex cloud solutions. Speaker Bio: Prior to Data Storage Corporation (DSC), Mr. Piluso founded North American Telecommunication Corporation, a facilities-based Competitive Local Exchange Carrier licensed by the Public Service Commission in 10 states, serving as the company's chairman and president from 1997 to 2000. Between 1990 and 1997, Mr. Piluso served as chairman & founder of International Telecommunications Corporation, a facilities-based international carrier licensed by t...
There are lots of challenges in IoT around secure, scalable and business friendly infrastructure for enterprises. For large corporations, IoT implementations are one of the top priorities of the decade. All industries are seeing a competitive need to sustain by investing in IoT initiatives. The value addition comes from improved customer service, innovative product and additional revenue streams. The data from these IP-connected devices can be leveraged for a variety of business applications as well as responsive action controls. The various architectural building blocks of an IoT ...
Recent technology advances in miniaturization has positioned the wearables as the pinnacle of technology convergence with the human body. We inquire if wearables are mere standard miniaturized devices extended with the connectivity and present our views on considerations like design, applications, performance, efficiency, interoperability, usage scenarios, human device interaction and consequent trade-offs enabling wearables to impart optimal value.
In this session we look at creating interactive communications via the web by adding messaging, file transfer, and group communication (group chat and audio/video conferencing) into the web experience. We will also discuss potential applications of this technology in areas including B2B, B2C, P2P, and gaming. Peter is Technical Director at Acision. He graduated from The University of Edinburgh in 2000 with a BSc (Hons) in Computer Science. After graduation Peter worked on a PSTN switch developing signalling stacks for SS7, ISDN and similar protocols and creating advanced routing and serv...
SYS-CON Events announced today that AIC, a leading provider of OEM/ODM server and storage solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. AIC is a leading provider of both standard OTS, off-the-shelf, and OEM/ODM server and storage solutions. With expert in-house design capabilities, validation, manufacturing and production, AIC's broad selection of products are highly flexible and are configurable to any form factor or custom configuration. AIC leads the industry with nearly 20 years of ...
SYS-CON Events announced today that Vicom Computer Services, Inc., a provider of technology and service solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. They are located at booth #427. Vicom Computer Services, Inc. is a progressive leader in the technology industry for over 30 years. Headquartered in the NY Metropolitan area. Vicom provides products and services based on today’s requirements around Unified Networks, Cloud Computing strategies, Virtualization around Software defined Data Ce...
Enterprise IoT is an exciting and chaotic space with a lot of potential to transform how the enterprise resources are managed. In his session at @ThingsExpo, Hari Srinivasan, Sr Product Manager at Cisco, will describe the challenges in enabling mass adoption of IoT, and share perspectives and insights on architectures/standards/protocols that are necessary to build a healthy ecosystem and lay the foundation to for a wide variety of exciting IoT use cases in the years to come.
Containers and microservices have become topics of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 16th Cloud Expo at the Javits Center in New York June 9-11 will find fresh new content in a new track called PaaS | Containers & Microservices Containers are not being considered for the first time by the cloud community, but a current era of re-consideration has pushed them to the top of the cloud agenda. With the launch of Docker's initial release in March of 2013, interest was revved up several notches. Then late last...
SYS-CON Events announced today that B2Cloud, a provider of enterprise resource planning software, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. B2cloud develops the software you need. They have the ideal tools to help you work with your clients. B2Cloud’s main solutions include AGIS – ERP, CLOHC, AGIS – Invoice, and IZUM
There is no doubt that Big Data is here and getting bigger every day. Building a Big Data infrastructure today is no easy task. There are an enormous number of choices for database engines and technologies. To make things even more challenging, requirements are getting more sophisticated, and the standard paradigm of supporting historical analytics queries is often just one facet of what is needed. As Big Data growth continues, organizations are demanding real-time access to data, allowing immediate and actionable interpretation of events as they happen. Another aspect concerns how to deliver ...
SYS-CON Events announced today that MangoApps will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY., and the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. MangoApps provides private all-in-one social intranets allowing workers to securely collaborate from anywhere in the world and from any device. Social, mobile, and easy to use. MangoApps has been named a "Market Leader" by Ovum Research and a "Cool Vendor" by Gartner...
The world's leading Cloud event, Cloud Expo has launched Microservices Journal on the SYS-CON.com portal, featuring over 19,000 original articles, news stories, features, and blog entries. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. Microservices Journal offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. Follow new article posts on Twitter at @MicroservicesE