Part 1: What the Infrastructure Needs to do

Martin Walker

You can’t always get what you want,

But if you try sometimes well you might just find,

You get what you need.

Mick Jagger and Keith Richards

It is very common in banking, writing and consultancy to start with an explanation of the broad categories of what people and systems do and the organisational structure within which they do them. This has value, but unfortunately often comes down to drawing a series of boxes containing other boxes and perhaps boxes in those boxes, while at the same time imploring people to think outside of the box and be innovative. One of the unfortunate consequences of this type of thinking can be replicating the problems of the past, and sometimes even making things worse – where vaguely defined labels on those boxes drive poor decision-making about how to reorganise things.

The concept of input-processing-output (IPO) is one of the simplest and most powerful ideas in computer systems (or process design in general), and will be used throughout this book. It is not only a powerful concept, but a simple one that the non-technical reader can use to cut through much of the unnecessary complexity in IT. At the most basic level, a system uses