Mobile Computing

One of the things that interests me about mobile computing are the architectural implications of decoupling. If speech is even a possibility for the medium term, then anything speakable needs to be put into a separate layer. (Does this mean that the remaining layers are unspeakable?) Just as, if there is a possibility that someone will be accessing your business process via a WAP phone, then you may need to reconsider precisely what aspects of the application should be isolated into the interface layer. (Thus it's not enough simply to label the layers of an architecture - it's necessary to specify the contents of each layer to some degree of precision. This is a question of stratification.)

New technologies potentially expose the limitations of yesterday's architectures. Structures that we thought were technology-independent turn out to have unexplored technical assumptions. We need to develop more robust structures and solutions, which would be more capable of accommodating tomorrow's technologies.

Speech recognition raises the question - where is the conversion going to be? We might expect a long debate on the relative advantages of fat phones (where the speech/data conversion and a fair amount of processing is done in the handset) and thin phones (where everything is done at the server end). But for me one of the lessons of the client/server saga was that much too much time was wasted trying to determine and fix the optimum degree of client fatness; and of course a lot of software architects now regret past decisions on fatness/thinness. In my view, what makes more sense is to structure a solution so that the fatness/thinness is itself isolated from the rest of the solution and can be varied tactically - we should be able to migrate functionality to and from the handset as the costs and point technologies change over time.

One of the key pieces of functionality that could be placed in the telephone handset (supported by the telco) is your identity service. When I ring my insurance company, my telephone might already knows my customer number, as well as the various policies I hold with this company. This would short-cut a lot of the automatic menus I currently have to pass through before talking to a callcentre employee. My phone might even be able to perform some degree of authentication on my behalf. Vodaphone is now offering a service called m-pay, where your credit card details are held securely at the server end and don't have to be spoken or sent when you buy something over the phone.

What we can celebrate is that some of the old strategic concerns have gone away. Voice versus data (or pictures). Fat versus thin. Microsoft versus IBM. Microsoft versus Sun. Pay-by-bank versus pay-by-phone. These are ceasing to be strategic issues, and are now becoming merely tactical. The strategic issues are now somewhere else.

CBDI Telecoms Report
More discussion on the fat/thin client issue