26 February 2008

What is a system?

By Andrew Clifford

Defining "IT system" creates a powerful tool for IT management.

When I talk to people about system governance, they always ask how I define "system".

I used to gloss over the answer. I though that the concept of system was an artefact of the method, needed to make assessment easier. But slowly I realised that the concept of system is a core part of the method that creates a powerful management tool.

There are three parts to the definition of "system" used by system governance: the definition of IT, the breakdown of IT into systems, and what is included as part of a system.

In a strict sense, IT can be defined as the automation of the storage, processing and communication of information.

This strict definition of IT excludes many IT-related processes:

IT is the technology itself, not the work of the IT department nor the work of the broader business that uses the IT.

To make it manageable, the entire body of IT needs to be broken down into separate, non-overlapping systems. The best starting point is the business applications that are recognised in the organisation. This is never definitive, and breaking down IT into systems always needs some creativity.

A system breakdown should include technical systems. Some technical infrastructure is just a layer of capability, like a database, that only exists as part of another system, and is not a separate system. Some technical infrastructure does have an independent existence, like systems management software, and should be considered a system in its own right.

There are no hard and fast rules about breaking IT down into systems. It is a choice about how you want to manage. It is more important that you clearly define the systems, and consistently use those definitions, than precisely what the system definitions are.

The definition of "system" includes everything that supports the information automation: application software, system software, hardware, and operation and support processes. A system is a slice through the stack of technology and the human infrastructure that supports it.

Operation and support processes are included as part of the system because the IT can not deliver information automation without them. Other IT processes, such as project management and business analysis, are not part of the system because they are not required to deliver automation day-to-day.

The main benefit of this definition of systems is that it makes IT easier to understand. Systems provide a coherent structure that makes sense of all the components of IT: software, servers, databases, support processes, and so on. It provides a structure for communicating IT to a general audience, and for managing the technical details of IT.

This definition is hugely valuable. It distinguishes the provision of IT from other contributions of the IT department (such as business change), which makes each easier to manage. It provides a handle for all technology, operation and support activities. It allows us to discuss IT in a meaningful way with business colleagues.

The concept of "system" is not a weakness of system governance. It is a powerful tool.