revision lesson 1 3.3.2: designing computer-based information systems
TRANSCRIPT
Revision Lesson 1
3.3.2: DESIGNING COMPUTER-BASED INFORMATION SYSTEMS
THIS PRESENTATION COVERS:• Processing Systems
• Designing the user interface
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.
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.
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.
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.
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)
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
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.
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.
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.
Quantity of information
Font
Colour Layout
Complexity of language
Controls
HCI
DESIGN PRINCIPLES
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.
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.
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.
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.
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)
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
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.
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.
METHOD OF INPUT• Usually input methods include keyboard and mouse.
• Touch screens and audio inputs are also becoming more popular.
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.
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.
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.
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
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
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.
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!