Archive for November, 2009

Seven Observations On Software Maintenance And FOSS

Monday, November 30th, 2009

By CJ Fearnley

The November 2009 issue of Communications of the ACM (CACM) has a very interesting article by Paul Stachour and David Collier-Brown entitled “You Don’t Know Jack About Software Maintenance”. The authors argue energetically for using versioned data structures and “continuous upgrading” to improve the state of the art of software maintenance.

The piece got me thinking about FOSS (Free and Open Source Software) and “continuous upgrading”. Here are seven observations on FOSS software maintenance that occurred to me as I reflected on the CACM article:

  1. FOSS projects “continuously” apply bug fixes and feature enhancements at no additional cost to their users. By applying these improvements “continuously”, the user reaps a steady stream of “interest payments” providing ever-improving security, performance, and functionality.
  2. Since FOSS incurs no licensing or license management costs, upgrading FOSS is not hindered by capital expenses.
  3. Typically support in FOSS projects is focused on the current stable version. Therefore, upgrading to the current stable version is the preferred way to receive the best support from FOSS communities.
  4. One of the key reasons behind Debian‘s strong track record of “continuous upgrading” is its way of handling the tricky issues involved with dependent library upgrades (such as libc6,, & etc). The chapter on Shared Libraries in the Debian Policy Manual details a proven method to effectively handle library upgrade issues (including its sophisticated handling of versions).
  5. When upgrading is applied routinely and “continuously”, it becomes crucial to support customizations across upgrades which can be one of the biggest obstacles to a smooth upgrade (see my earlier post on customization and upgradeability). One reason for Debian’s effectiveness in this regard is its robust configuration file handling policy.
  6. It is worth noting that the “continuous” implied here is not the one emphasized in dictionaries (which takes its nuances from the mathematical / physics concept of “no interruptions” and the epsilon-delta definition that students of Calculus learn). That concept of “continuous” is impossible in systems administration which is necessarily discrete as are all computer operations. The connotation required here is, perhaps, “unending”, or “eternal” or somesuch.
  7. The “right” frequency for “continuous” upgrades is a complex tradeoff between business requirements and upgrade infrastructure maturity. Debian and Ubuntu provide vary mature support for “continuous upgrading”. They support the upgrade of production servers through release after release after major release with minimal downtime or risk of a glitch that could affect users. Their current release frequency of about 2 years may be the best we can do given the current state of the art of software maintenance. I hope we can learn to increase the frequency as better engineered upgrade policies are developed.

I prefer the name “eternally regenerative software administration” over “continuous upgrading”. It avoids the philosophical problems with the word “continuous” and emphasizes the active, “ecological” approach needed to envision the engineering of “regenerativity” in software. By that I mean software maintenance should involve building the system so each new version enables installation of the next while facilitating management of any customizations and integration with other software (including libraries and other “helper” applications). Regenerativity is the process of growth and change used by Nature itself. Software maintenance needs to follow similar principles.

Crossroads in FOSS Projects: Some Business Considerations

Tuesday, November 24th, 2009

By CJ Fearnley

At our Seminar last month, Managing FOSS to Lower Costs and Achieve Business Results, several participants asked about the dynamics of FOSS (Free and Open Source Software) projects that reach a crossroads (a failure, a merger, loss of key personnel, etc). I had not expected that concern because with commercial software, it seems to me, the problem is more severe. When you have the source code and the right to modify and redistribute it, the source gives many more options (and its freedoms provide many more protections) than when commercial software goes bankrupt or gets bought by a competitor for instance.

But the reason for the questions may be a lack of understanding about how FOSS projects work. They involve individual human beings, perhaps just a single person or, more likely, several people from many organizations and even different cultures around the world joined in common purpose. For various cultural reasons, the project may be “owned” by an entity — usually a non-profit, but some are for-profit or even government owned, while others may simply be an “ad hoc initiative”. Some projects have explicit constitutions and defined processes for organizing the work and handling problems others are more informal.

At any time, any human social structure can experience a crossroads that could lead it to fail suddenly or wither on the vine in a gradual descent into “oblivion”. The cause of the failure will shape the results, but a very common situation is that conflicting visions or approaches for the project result in a “fork”. Then a sub-group of the original project takes the source code and starts a “new” project to develop the code in a new direction. Sometimes the original project “dies” and sometimes both continue resulting in two projects. Since multiple FOSS projects serving the same function or market incur inefficiencies due to duplicate development, there is a strong cultural value in the FOSS world to try to find a way to accommodate everyone in the project and prevent forks. When it works, the result is great software that meets everyone’s needs. But the reality is that often it is more effective to have multiple implementations of the same functionality so that each can be optimized for distinct objectives. Frequently one cannot know which approach will be best until many years of development and evaluation have transpired.

I recently learned about a FOSS project that forked when a friend asked me to copy some files to his new “My Book Essential”, a Western Digital product that provides 1TB of USB (Universal Serial Bus) storage. The My Book uses the poorly documented, non-free NTFS (New Technology File System). Linux has three projects that support NTFS: an in kernel driver, ntfsprogs (the Linux-NTFS project), and NTFS-3G. It turns out that all three were available for my Debian Lenny (5.0.3) system. First, I tried the in kernel support and learned that it was still read-only. Then I tried ntfsprogs which failed to mount the My Book:

NTFS-fs error (device sdc1): load_system_files(): Volume is dirty. Mounting read-only. Run chkdsk and mount in Windows.

I realized that since it was a new device it probably did not ship from the factory with a dirty volume. It was probably a bug. So I tried NTFS-3G which worked very well. In my research of the situation I was able to determine that both NTFS-3G and Linux-NTFS are under active development and have features missing from the other. So each has value and I’m glad my distribution included both. In Debian Lenny, the NTFS-3G driver has better support for writing files.

This illustrates one of the benefits of a crossroads in a FOSS project: you can end up with two good tools to add to your toolbox!

Forthcoming Design Science Symposium and Systems Administration

Tuesday, November 3rd, 2009

By CJ Fearnley

Ever since I started doing systems administration, I’ve been interested in applying Buckminster “Bucky” Fuller’s comprehensive anticipatory design science to the task. Bucky extolled the virtues of a comprehensive approach. Put bluntly, the comprehensive perspective says “since what you don’t attend to will get ya, you had better consider everything. Or said positively: only by considering all elements in a system and all its interrelationships with other (relevant) systems can you ensure reliable on-going operation. In addition, the proactive or anticipatory approach is essential to prevent system complexities from impacting operations. I think of design as human initiative-taking to provide a service or artifact and science as experience-based learning. Evidently, design science is implicit in the work of systems administrators. I think the discipline of comprehensive anticipatory design science can be positively applied to the practice of systems administration.

So I am excited that on November 14 & 15, I will be attending the Synergetics Collaborative’s two-day Symposium on “Design Science” at the Rhode Island School of Design (RISD). Together with the organizing committee, we (I serve as volunteer Executive Director of the Synergetics Collaborative) have put together a program that will develop a deeper understanding of design science. So even though computer systems administration is not on the agenda, I think anyone with a problem-solving focus in their work (including systems administrators) would benefit by attending.

To find out more about this exciting event visit the Design Science: Nature’s Problem Solving Method Symposium home page here.