Mike Beach is obviously a fellow who likes to ask the hard questions. This time he is asking how Higgins differs from a virtual directory. There is some level of confusion out there so in order to add a little clarity my answer would be that the difference is one of perspective and granularity. QED.

Well, I suppose I ought to explain that a little. You see, Higgins is either a lego brick or a gear stick. Which it is depends on whose favourite analogy you use, Dale’s or Kim’s. Dale might say it is a lego brick that you use to build other things, and Kim might say that it is a gear stick that works in a way we all understand because it works like other gear sticks. Or something like that. In any case, the point is that Paul Trevithick says Higgins is a framework. I suspect most would be happier with an explaination that it is a set of API’s for representing information about people along with the glue to connect one api to another and some other goodies like common schema. In object oriented pattern theory/design/voodoo it fits into the bridge pattern. Higgins is the bridge with the common interface to multiple systems. Yes, it’s a version of that lego brick that must also exist in virtual and meta-directories. So much for granularity.

Changing perspective lets get to the gear stick. Part of the Higgins project as a whole is to build a CardSpace like identity selector. Lets be clear - Higgins is the framework, the identity selector is one possible use of the framework. An identity selector requires a gear stick and Higgins looks like a gear stick. Of course, gear sticks don’t exist in a vacuum, they are usually accompanied by a steering wheel, a brake pedal, and an accellerator pedal. There needs to be a clutch pedal to aid gear changes and in some of the more luxurious gear stick implementations there will be a drivers seat right next to them. So, the Higgins identity selector is a bunch of co-operating parts that in some people’s blogs might look like a car, and the Higgins framework is one of the parts necessary to build a car.

Virtual Directories? Space ships, virtual directories are space ships with gear sticks. But that’s for another blog.