[GRLUG] Mac & ??: reverse-URL file and directory names

[Matt Behrens]

On Apr 16, 2013, at 11:36 AM, Eric Beversluis <ebever at researchintegration.org> wrote:

> I've come across this occasionally and see it on my Mac--eg, under
> Library/Cache: directory and file names that look like reverse urls:
> 
> com.barebones.textwrangler
> or 
> com.adobe.ARM
> 
> I'm not even clear how I would Google for an explanation of when and how
> and why this naming convention is used. E.g., if we're naming files on a
> computer with no internet connection, why start with 'com'? etc.


It's a way to leverage the domain name system to create namespaces that organizations can use with a reasonable guarantee of uniqueness, without relying on another registration authority.  (For a full guarantee, see tag: URIs: http://tools.ietf.org/html/rfc4151)  In this way, even if several companies had a software package named e.g. "ARM", they could each create their own folder that they could assert full control over.

I believe the backwards bit is a holdover from Java packages, e.g. com.example.package would result in class files being put in com/example/package, which in turn organizes all the packages from example.com in one directory.
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