Archive for the ‘Software Development’ Category

Ben Collins-Sussman posted an interesting blog entry “Subversion’s Future?”, where one of the main points made was that while distributed source control systems are OK for smallish/open-source projects, Subversion’s sweet spot is with huge projects. I couldn’t disagree more. And here’s my response.

I’ve been using the distributed source controls systems for more than a decade and been watching other big projects using the distributed systems and it seems to me the DVCS provide the more benefits the bigger the size of the project. What are the characteristics of a huge project? In most cases, it means that there is a big team working on it. Big team means global team, all over the globe. This is not an “open-source thing”, this is a reality of corporate software development too. Most companies (well, at least those who are actually producing huge projects) are global companies, with offices in the U.S, Europe, India, etc. Working globally on the central repository *is* painful and slow. Tried to bisect the regression introduced between the releases, switching between many  revisions, tried to follow the history of some code in Subversion? Doing this when the main repository is overseas is not fun.

A big team of engineers is typically organized in a hierarchy of smaller sub-teams focusing on particular area of the product. Again, it’s much more natural to organize a hierarchy of workspaces matching the structure of the organization. There are many benefits to that approach: mostly the members of such sub-team care about their area, not touching/changing anything in other places. And they better know their code, so they could find/fix new bugs and regressions faster. Typically, there is a special QA force for each sub-team, trained and specialized in testing particular area. Once they tested/OK’ed the particular state of the team code, it can be pushed upwards to the integration workspace. Thus, members of other teams won’t even be disrupted by local problems/regressions, since they would get the more stable and better tested code. The distributed source control allows to do that beautifully and naturally. Doing this in Subversion is seriously painful.

Also, what are those mythical huge projects that nobody knows about? How about OpenSolaris or Linux?Are they “huge enough”? How about Mozilla or Ubuntu or NetBeans or JDK or MySQL? And all these projects do use distributed source control tools. Solaris and Java SDK only recently were open-sourced. Before that they were, by all means, huge commercial software projects, each with many, many years of development by hundreds of people. They were developed with distributed source control system. There *is* a reason why Linux never used CVS/Subversion and why even commercial non open source distributed system was used to develop Linux (since there were no good open DVCS at the time). And the reason, of course, is that distributed source control helps managing the overwhelming complexity of the huge projects much better than centralized one.

One other point in the Ben’s blog entry was about usability and ease of use of Subversion. Yeah, it is easier to use in simple scenarios, but once the size of a project grows, it gets harder and harder. Besides, if engineers are smart enough to develop and maintain a huge project, adjusting to distributed source control systems would be piece of cake! And for those folks who are stuck with Subversion, there is a great git-svn tool that would allow to leverage the power of distributed source control while working with centralized Subversion repository.

I’m not really saying that Subversion is “bad”. It was actually great for its time, but now there are better and smarter tools out there.

For some reason, code review tools topic is my “soft spot”, and I keep watching the area hoping to find the ideal solution. Until now, the closest thing to my ideal was Mondrian code review tool by Python author, Guido van Rossum. The excellent Mondrian video presentation is here, and I highly recommend it for everyone who interested in code review tools. Too bad, the Mondrian is tightly tied to Google infrastructure and is not open source.

But today I saw the announcements (here and here) by VmWare engineers who just published a new code review tool, Review Board, written also in Python, but unlike the Mondrian, under open source license, and immediately available! There is also an online demo site, to play with the new tool. The Review Board supports Perforce and Subversion (for now), and looks great.

I’ll play a little bit more with the Review Board, and report back.

I must admit, I’m a book freak. I read a lot of technical books, just for fun. In early days, when I was in California, it was easy to find a good place with lots of new technical books and with good coffee. Now, being in Germany, I mostly rely on online resources.

So while I do enjoy reading paper books, I tend to use online libraries more and more. I’m aware of the following two online libraries:

• Safari Library
• Books24×7

Basically, hundreds and hundreds of technical books are present in both libraries, and with good share of new, recent books. It seems that Safari Library has more extensive book collection, with, naturally, most of O’Reilly titles. But Books24×7 also has lots of books that are not present in Safari. So, the libraries complement each other nicely.

In Safari Library, there’s also a “Rough Cuts” section, with preliminary versions of books that are not yet in stores! For both libraries, there are RSS feeds provided, with the latest book arrivals, so it’s easy to be up-to-date.

But I guess, the most valuable service I get from online libraries is the search. Just think of it, fully indexed content of ALL available in the library books! Now, any time I have a need to refresh my knowledge on any specific topic, I directly go to these two resources and search there. Most of the time, there are quite few books on the topic. And the quality of the info in the books is generally much higher then in the typical online resources.

Naturally, the service is not free, and it definitely helps to have a corporate account in these libraries! But even before my company provided such account, I was a happy paying customer of Safari Library – the basic subscription plan doesn’t cost much.

If I had to select only one library, I’d go with Safari. It has better user interface, better books, more intelligent search, ability to download book chapters in PDF format.

And if I had to select only one book, I’d really recommend “Code Complete” by Steve McConnell. Take a look, this book radically changed the way I look at my code.