Welcome!

Linux Containers Authors: Automic Blog, Elizabeth White, Olivier Huynh Van, Derek Weeks, William Schmarzo

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 T-Mobile will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. As America's Un-carrier, T-Mobile US, Inc., is redefining the way consumers and businesses buy wireless services through leading product and service innovation. The Company's advanced nationwide 4G LTE network delivers outstanding wireless experiences to 67.4 million customers who are unwilling to compromise on ...
SYS-CON Events announced today that Infranics will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Since 2000, Infranics has developed SysMaster Suite, which is required for the stable and efficient management of ICT infrastructure. The ICT management solution developed and provided by Infranics continues to add intelligence to the ICT infrastructure through the IMC (Infra Management Cycle) based on mathemat...
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 20th Cloud Expo, which will take place on June 6-8, 2017 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 add...
SYS-CON Events announced today that Cloudistics, an on-premises cloud computing company, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloudistics delivers a complete public cloud experience with composable on-premises infrastructures to medium and large enterprises. Its software-defined technology natively converges network, storage, compute, virtualization, and management into a ...
SYS-CON Events announced today that SD Times | BZ Media has been named “Media Sponsor” of SYS-CON's 20th International Cloud Expo, which will take place on June 6–8, 2017, at the Javits Center in New York City, NY. BZ Media LLC is a high-tech media company that produces technical conferences and expositions, and publishes a magazine, newsletters and websites in the software development, SharePoint, mobile development and commercial UAV markets.
"I think that everyone recognizes that for IoT to really realize its full potential and value that it is about creating ecosystems and marketplaces and that no single vendor is able to support what is required," explained Esmeralda Swartz, VP, Marketing Enterprise and Cloud at Ericsson, in this SYS-CON.tv interview at @ThingsExpo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Why do your mobile transformations need to happen today? Mobile is the strategy that enterprise transformation centers on to drive customer engagement. In his general session at @ThingsExpo, Roger Woods, Director, Mobile Product & Strategy – Adobe Marketing Cloud, covered key IoT and mobile trends that are forcing mobile transformation, key components of a solid mobile strategy and explored how brands are effectively driving mobile change throughout the enterprise.
My team embarked on building a data lake for our sales and marketing data to better understand customer journeys. This required building a hybrid data pipeline to connect our cloud CRM with the new Hadoop Data Lake. One challenge is that IT was not in a position to provide support until we proved value and marketing did not have the experience, so we embarked on the journey ourselves within the product marketing team for our line of business within Progress. In his session at @BigDataExpo, Sum...
Keeping pace with advancements in software delivery processes and tooling is taxing even for the most proficient organizations. Point tools, platforms, open source and the increasing adoption of private and public cloud services requires strong engineering rigor - all in the face of developer demands to use the tools of choice. As Agile has settled in as a mainstream practice, now DevOps has emerged as the next wave to improve software delivery speed and output. To make DevOps work, organization...
SYS-CON Events announced today that MobiDev, a client-oriented software development company, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MobiDev is a software company that develops and delivers turn-key mobile apps, websites, web services, and complex softw...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
What sort of WebRTC based applications can we expect to see over the next year and beyond? One way to predict development trends is to see what sorts of applications startups are building. In his session at @ThingsExpo, Arin Sime, founder of WebRTC.ventures, will discuss the current and likely future trends in WebRTC application development based on real requests for custom applications from real customers, as well as other public sources of information,
China Unicom exhibit at the 19th International Cloud Expo, which took place at the Santa Clara Convention Center in Santa Clara, CA, in November 2016. China United Network Communications Group Co. Ltd ("China Unicom") was officially established in 2009 on the basis of the merger of former China Netcom and former China Unicom. China Unicom mainly operates a full range of telecommunications services including mobile broadband (GSM, WCDMA, LTE FDD, TD-LTE), fixed-line broadband, ICT, data communica...
SYS-CON Events announced today that Ocean9will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Ocean9 provides cloud services for Backup, Disaster Recovery (DRaaS) and instant Innovation, and redefines enterprise infrastructure with its cloud native subscription offerings for mission critical SAP workloads.
Things are changing so quickly in IoT that it would take a wizard to predict which ecosystem will gain the most traction. In order for IoT to reach its potential, smart devices must be able to work together. Today, there are a slew of interoperability standards being promoted by big names to make this happen: HomeKit, Brillo and Alljoyn. In his session at @ThingsExpo, Adam Justice, vice president and general manager of Grid Connect, will review what happens when smart devices don’t work togethe...
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
SYS-CON Events announced today that Technologic Systems Inc., an embedded systems solutions company, will exhibit at SYS-CON's @ThingsExpo, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Technologic Systems is an embedded systems company with headquarters in Fountain Hills, Arizona. They have been in business for 32 years, helping more than 8,000 OEM customers and building over a hundred COTS products that have never been discontinued. Technologic Systems’ pr...
SYS-CON Events announced today that Auditwerx will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Auditwerx specializes in SOC 1, SOC 2, and SOC 3 attestation services throughout the U.S. and Canada. As a division of Carr, Riggs & Ingram (CRI), one of the top 20 largest CPA firms nationally, you can expect the resources, skills, and experience of a much larger firm combined with the accessibility and attent...
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From ...
SYS-CON Events announced today that HTBase will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. HTBase (Gartner 2016 Cool Vendor) delivers a Composable IT infrastructure solution architected for agility and increased efficiency. It turns compute, storage, and fabric into fluid pools of resources that are easily composed and re-composed to meet each application’s needs. With HTBase, companies can quickly prov...