I've been involved in database development for 30 years and CM development for over a quarter century. I'm confused. Why is it so difficult to get working multi-site solutions? The specification is clear, to start off anyway: I want to see the same thing whether my client is connected to the London server or the New York server.

This month we do a bit of a context switch from the world of parallel development to the world of concurrent, parallel, and distributed systems design (and then back again). The purpose is to see if any of the same patterns of concurrent, parallel, and distributed processing apply to the case of concurrent, parallel, and distributed development.

You may now be tired of hearing me say it, but I will say it again:  Your repository contains every version of everything which has ever been checked in to the repository.  This is a Good Thing.  We sleep better at night because we know that our efforts are always additive, never subtractive.  Nothing is ever lost.  As the team regularly checks in more stuff, the complete historical record is preserved, just in case we ever need it. But this feature is also a Bad Thing.  It turns out that keeping absolutely everything isn't all that useful if you can't find anything later. 

Many times when managers first consider parallel development, it appears to be a very effective way to manage changes to concurrent streams of development. This is somewhat true if the project uses an SCM technology that allows for stable branching and establishes discreet project and maintenance branches. However, what is often forgotten is that while branching is a great way to separate code changes, at some point merging will have to occur. This article provides guidance for approaching and performing parallel development.