Computer Systems

A COMPUTER is an electronic, programmable data machine.

A SYSTEM is a collection of parts that work together for some defined purpose.

A COMPUTER SYSTEM is a collection of hardware and software that works together to achieve some data processing task.

Systems recieve INPUTS from the outside. They PROCESS these inputs. They OUTPUT the result of the processing.

A system is separated from the outside world by a SYSTEM BOUNDARY. These boundaries are often called INTERFACES.

Most aspects of our lives are affected by computer systems. They have led to:

• Improved quality in manufacturing - robotic machinery is more accurate than humans.

• Cheaper manufacturing - automation reduced wage costs and allows 24/7 working.

• Faster access to information - many jobs can be done more quickly.

• Better decision making - with lots of facts organised and available, decisions can be better informed.

• New ways of doing business - more buying online, more choice, cheaper goods; facilities such as the internet and ATMs would not be possible without computer systems.

• New ways of communicating - email, SMS, cell phones - are being developed all the time.

Car engine management - Temperature, CO2 levels, speed.

Holiday booking - Dates, desinations, credit card details.

Washing machine - Water levels, temperature, dirtiness.

Satnav - Signals from satellites, inputs from user.

ATM - Card details, PIN, user requests.

Travel card - Location of station, bus route number, top-up information, money.

Car engine management - Check values against set parameters, produce fault codes.

Holiday booking - Check availability, produce documents.

Washing machine - Check values, determine washing parameters.

Satnav - Check position, locate on map, output map.

ATM - Check balance, Adjust balance of account.

Travel card - Calculate journey cost, adjust balance.

Car engine management - Signals to carburettor, data to engine diagnostics.

Holiday booking - Itineraries, air tickets, hotel reservations.

Washing machine - Signals to motor, heater, timer.

Satnav - Route, places of interest, warnings.

ATM - Balance, cash.

Travel card - Open gate to station, display balance.

Personal computers such as desktops, laptops, notebooks ad tablet computers, as well as smart phones, are designed to perform multiple tasks. Various applications can be loaded so that they can be used for a variety of purposes.

Dedicated systems are specially produced to perform a single function or set of functions. For example, a ticket-vending machine at a train station is not likely to be used for another purpose.

Control systems are computer systems that control machinery, rather than produce output for humans to read and respond to. They are particularly important in manufactoring processes but are increasingly part of common domestic and personal gadgets. Industrial robots are an important application of control systems.

Embedded systems are computer systems that are part of a larger system. They are usually also control systems. They include portable devices:

• digital watches
• satnavs
• cameras
• MP3 players.

They also include larger installations, such as:

• traffic lights
• controllers of machinary in factories.

Embedded systems can be very simple or highly complex, such as avionics systems in aircraft. Most cars now have up to 50 computer systems looking after things like fuel flow, window control, cruise control and fault management.

Expert systems are computer systems designed to behave like a human expert. 

They have three component parts:

• a knowledge base - a database of facts
• an inference engine - software that makes deductions using the knowledge base
• an interface - to allow human user access to the system.

They are commonly used for:

• diagnosing diseases
• finding faults in machinary
• choosing complex products, such as mortgages and insurance policies
• suggesting purchases to customers
• making credit checks

Management information systems bring together the information from all parts of an organisation so that managers can make sensible decisions.

They cover:

• technology
• data
• people

They typically produce regular reports based on the organisation's data.

Examples of management systems:

• Decision Support Systems are used by middle management to support day-to-day decision making
• Executive Information Systems produce reports using data from throughout an organisation and support decisions about the organisation's strategy
• Office Automation Systems automate workflow and maximise the efficiency of data movement
• School Management Information Systems deal with school admistration, teaching and learning.