3.3.2: Designing computer-based information systems

1. 3.3.2: Designing computer-based information systems Revision Lesson 1

2. This presentation covers: • Processing Systems • Designing the user interface

3. Processing Systems • For the exam you need to know about: • Mode of operation (Discuss processing, response time and user interface) • Batch, Interactive and Real-Time processing systems. • Operating systems (Describe characteristics) • Single user, Multi-user, Multi-tasking, Interactive, Real-time, Batch processing and Distributed processing.

4. Mode of operation • The mode of operation is essentially how processing is carried out. • When data is processed in groups, it is referred to as batch processing. • When data is processed one item at a time and requires user responses, it is referred to as interactive processing. • When data is processed immediately after being input, it is referred to as real-time processing.

5. Batch Processing • Processed when the system is not busy (usually at night). • This means that there is usually a delay between the data being input into the system and the data being processed. • There is no need for user interaction meaning it is not necessary to have a GUI. A command line interface will suffice. • Usually used for processing monthly bills.

6. Interactive Processing • iEach transaction is completed before moving onto the next. • Dependant on response and action from the user. • GUI is necessary for user to interact with the system. • Used in ATMs, EPOS and ticket booking.

7. Real-Time Processing • The data is processed as soon as the processor receives it. • The data is processed within seconds of being input (usually no more than 4 seconds). • There is sometimes a GUI but the systems often run automatically because of the high data input rate (usually recorded via sensors). • Used in transport: • (cars – traction control and stability control) • (aeroplanes – autopilot)

8. Operating Systems • Single-user • One user at a time • Users must log off before another can use it • Multi-user • Allows more than one user at a time • Usually runs over a network • OS manages each user to ensure conflicts do no occur

9. Operating Systems • Multi-tasking • Allows the processor to ‘apparently’ deal with multiple processes at the same time. • Actually allocates chunks of time to different processing requires and flicks between them. • Interactive • Requires direct user interaction whilst running. • Real-time • Usually embedded in another application and can run on their own with no user interaction, but might react to a stimulus caused by the user. • For example, the ECU of a car.

10. Operating Systems • Batch processing • Given a set of tasks to complete without user interaction. • Processes jobs when system is not in use or just before the processed data is required. • Distributed processing • Computers connected together sharing the work load. • Each computer processes parts of the job. • Results are later combined.

11. User Interfaces (Basics) • For the exam you need to know about: • Design Principles (Discuss design principles) • Colour, layout, quantity of information, complexity of language and type of controls. • Method of controls (Discuss methods for communication techniques) • Computer to person, Person to computer and computer to computer.

12. Design principles Quantity of information Font

13. Colour • Things to think about: • Do end users have any disabilities? • Colour blindness • Dyslexia • Colours can trigger reactions (Green is ok, Red is bad) and grab attention. • Limit the number of colours (4 per screen, 7 per sequence). • Colours can be used to code information.

14. Layout • Things to think about: • Consistent layout (between screens and applications). • Layout of information and data entry should be logical. • Important information and action points need to be in a prominent position. • Designing for easy learning and efficient use.

15. Font • Things to think about: • Easy to read. • Who are the end users and what are their needs. • What equipment will be used and possible ergonomics should be considered. • PC, Laptop and hand-held devices are all placed at different distances from the end user. • Styles should be applied appropriately for easy transfer of information.

16. Complexity of language • Things to think about: • Who are the end-users? • Complexity kept as low as possible. • All errors should be in the simplest of forms. • Help should be useful, not condescending. • All technical language should be minimal and fit for purpose.

17. Types of Control • Things to think about: • Ease of use: • Macros: Automate complex or repetitive tasks. • Buttons: Navigation or activate macros. • Forms: Assist in data entry (logical, validation and verification) • Menus. Allows actions to be selected (can hide inappropriate actions)

18. Methods of Dialogue • You need to be able to discuss methods of dialogue between a computer and a person, a person and a computer and a computer to another computer. • They main ways that computers and humans communicate is via a user interface. • Modern UI’s are graphical (GUIs). • They make use of: • Prompts • Input styles and methods • Feedback

19. Prompts • Prompts indicate something to the user. • In a command line interface the prompt will indicate that a command needs to be entered. • In a GUI, icons are used to prompt the user. • Menus are also used to prompt the user to select certain actions.

20. Nature of input • This describes how the input will be requested: • Question based • Form based • The next response could be determined by the last input.

21. Method of input • Usually input methods include keyboard and mouse. • Touch screens and audio inputs are also becoming more popular.

22. Feedback • Providing limited number of responses to select from. • Can be in the form of: • Menus and Sub-Menus. • Very specific options being available to control what the user can select.

23. Feedback • Providing limited number of responses to select from. • Can be in the form of: • Menus and Sub-Menus. • Very specific options being available to control what the user can select.

24. Taking the user into account • You need to be able to explain how a potential user’s: • Perception • Attention • Memory • Learning can be taken into account when designing an interface. • The presentation on my website goes into a lot of detail about different things to consider...but they all inter-relate with each other.

25. Perception • Users perceive inputs from sights and sounds. • Users have preconceived ideas about how things should be done. • Red text = Bad • Siren = Bad • Ding = Good • BONG = Bad

26. Attention • Most people have a limited attention span. • Designers need to think about how to increase the attention span of user: • Uncluttered screens • Easy to access information • Clearly labelled input areas • Pop up messages, flashing images and sounds can draw the user’s attention • Keeping menus consistent so they are easily used and understood • Keeping icon symbols consistent too – Floppy Disk for save icon

27. Memory • Keeping GUIs consistent with already made GUIs helps to shorten the learning curve. • Users make use of pre-existing memory experiences to help them learn. • Consistency aids in the recall of actions. • It is also important as people have preconceptions about how things should work based on prior experiences.

28. Learning • Must look at previous user experience. • New interfaces should try and match old system as far as possible. • On-screen help is really important. • Important to think about perception, attention and memory!