Info systems

The purpose of information systems are to;

• input data
• process (maintain files of data about the organisation)
• output information (produce information reports and other output)

The information requirement changes from one organisation to another, and within the organisation from one job function to another.

A manager will usually require summary information, whereas the person handling the day to day transactions will require quite detailed information.

A business computer based information system, is an information system where a computer plays a major role in the input, process, output functions. Often we will divide the areas into Hardware, software, data, procedures and people.

Subsystems

A computer based Information system consists of subsystems

• hardware
• software
• data
• procedures
• people

application/operation

The specific set of subsystems used - the specific equipment, programs, files and procedures - constitutes an information system application.

So information systems can have purchasing, accounting, or sales applications.

Since all information systems support other organisation systems, analysts must first study the organisation as a whole and consider its information details. Often organisation charts are used to describe how an organisations components relate to one another.

They do not however tell how the business system operates, since there are details that cannot be shown on an organisation chart.

Examples of such details include:

• Information channels - what interactions exist between people and departments that are not shown on the chart.
• Interdependencies - on which departments and components in the organisation is a particular element dependent.
• Key People and Functions - which individuals and elements in the system are most important for successful existence.
• Critical Communication Links - how does information pass back and forth between organisation components.