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!