Sufficiently Small

I’ve been following the progress of a continuous integration build manager called DamageControl for over two years now. DamageControl is a Ruby on Rails based framework for triggering builds of software, whenever there is a check-in to the source control system. Essentially it fulfils the same job as CruiseControl and Mozilla Tinderbox - detecting when a build has been broken by a bad check-in, but with an attractive web-front end and some nice configuration features. DamageControl interfaces very nicely to a variety of source control systems through the RSCM (Ruby Source Code Management) library.

I’ve ‘lurked’ on the DamageControl developers and user mailing lists long enough to get a feel for how the project is progessing. However, I’ve been disappointed that although DamageControl has gone through many version increments - I came in at DC 0.3, we’re currently around 0.6 there has never been anything approximating a stable release.

Now I know as much as the next open-source contributor how difficult it is to remain committed to a project, but lack of committment doesn’t seem to be the problem here. If DamageControl were a commercial offering, it condition would be diagnosed as ‘inability to ship’. DamageControl is perpetually undergoing, the next big refactoring, which it is promised will lead to a ’stable version’. As any experienced developer knows, software is never ‘finished’ and it is nearly always beneficial to re-write or refactor. However, every project has to break out of this loop at some point, if only temporality, to stabilize the code and benefit user feedback and bug reports from a specific version.

However today, after checking back at the DC site after six months I have given up hope, DamageControl has the following message on its site:

DAMAGECONTROL HAS HIBERNATED

It’s currently not under active development.

It’s not completely abandoned - development may pick up again once I …. get more time to work on it.

The first lesson is that not everything created atop Ruby on Rails will be rip-roaring success. The second lesson I take from this, for my own projects, is that there is enormous value in creating something that works and that is incrementally useful, even if it is merely the Simplest Thing That Could Possibly Work. The third lesson is that providing something that is easy to install and start actually using, hugely increases the probability of a project being successful; having to extract specific revisions from Subversion, and run them against very stringent Ruby, Rails and other package versions is a severe hindrance. Creating a community of motivated users around the product is fundamental to success. Rather this, than a sense of unrequited expectation amongst a group of potential users who find it difficult to get involved because the code train is never moving slowly enough to leap aboard.

By default Windows iTunes stores the music metadata, although not necessarily the music itself, in the current user’s My Music folder. For user Alice, this will be located in,

C:\Documents and Settings\alice\My Music\iTunes\

and for Bob in

C:\Documents and Settings\bob\My Music\iTunes\

which means that the two users can’t share settings, playlists and the like easily.

On a Unix-a-like system we could solve this with symbolic links by linking the two iTunes directories to a common location. Of course, everybodys know that symbolic links do not feature in Windows filing systems.

Or do they?

In fact NTFS supports a feature various known as Junction Points or Reparse Points which can be used to ‘mount’ other directories or even volumes onto the location of existing directories. The facility to create junction points is not exposed through the standard Windows user interface, presumably because of the havoc you can wreak if you don’t know what you’re doing. However, for those of us who know exactly what we’re doing, they’re just what the doctor ordered.

In order to create junction points you can use the free tool Junction Link Magic from Rekenwonder Software. We’ll use it to make iTunes multi-user!

The following procedure is documented prior to installation of iTunes. It is possible to retrofit this to an existing iTunes installation, but you need to take care to not lose your existing iTunes settings, and its not clear how to merge the settings of existing iTunes users.

First we need to create the common location that different Windows iTunes users will share. So whilst logged in as an Administrator, create the directory

C:\Documents and Settings\All Users\Documents\My Music\iTunes\

Before we can create the junction points themselves, we need to create ‘host’ folders in the correct locations, so create the following two directories:

C:\Documents and Settings\alice\My Music\iTunes\
C:\Documents and Settings\bob\My Music\iTunes\

Now, having installed Junction Link Magic, use it to create a Junction Points from each users iTunes directory to the common location. When you first launch Junction Link Magic it will spend a few minutes searching your file system for existing junction points. When this process is complete you will most likely see an empty list of junction points,

First we will create the junction point for Alice. Click the ‘Create’ button and select both Alice’s host iTunes folder, and the All Users iTunes< folder. Note under Windows XP the browser may show different directory 'user friendly' names such as All Users\Shared Documents\Shared Music\ instead of the true directory name All Users\Documents\My Music\ show in the label below the browser.