COMPUTER INTERFACES 1. The term interface means the link between the computer and the user; it refers to the means by which the user interacts with the.

COMPUTER

INTERFACES 1

The term interface means the link

between the computer and the user;

it refers to the means by which the user interacts with the

machine.2

What we see when we look at the

computer is a part of the interface

What we use to give commands to the computer is also a

part of the interface3

This means therefore that the interface is both

hardware and software.

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HARDWARE• Hardware comprises all the parts of a computer system you can see and

touch but not every item of hardware is a part of the interface. • All input and output devices form part of the interface as they are the

means by which the user gives and gets information to and from the computer.

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• In addition to the run of the mill input and output devices, the following are of special note :

• Touch screens• Sensors• Braille Keyboard• Non visual interfaces

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TOUCH SCREEN

What is A Touch Screen?

• A screen which acts as both an input and output device by allowing the user to interact with the computer by using his/her finger or a stylus to give commands or make selections by touching the screen.

Example of A Touch Screen

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SENSORS What is a Sensor?

• A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument.

• Many computerised industrial systems use sensors to pick up input data which is then transmitted to the main computer system for processing.

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SENSORS

• Sensors can detect changes in pressure, temperature, speed, etc

• The use of sensors means that no human input or interference is required

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What is A Braille

Keyboard?

• Keyboard marked with raised dots for the visually impaired.

Example of A Braille Keyboard

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BRAILLE KEYBOARDS

NON VISUAL INTERFACES

• A Non Visual Interface is a type of interface that allows the user to interact with the computer without seeing it

• Two important non visual interfaces are audio input to a microphone and output from a speaker,

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SOFTWARE

INTERFACES 12

SOFTWARES• Software is the name for all the programs

that computers use to perform different tasks.

• How the software looks and how one interacts with it, is the software interface

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There are three major types of software interfaces :

• Command driven interfaces

• Menu driven interfaces

• Graphical user interfaces

COMMAND

DRIVEN

INTERFACES

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COMMANDDRIVEN INTERFACES

• A Command Line or command driven

interface presents the user with a prompt on a blank screen and requires the user to interact with the computer system by typing in commands.

• Any command which is entered must be typed in the correct syntax to in order to perform the required operation.

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COMMANDDRIVEN INTERFACES

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COMMANDDRIVEN INTERFACES

Examples of programs which use a Command Driven Interface are:

Dos,

Linux and

Unix.

(Note that these are all operating systems)

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This is an example of a DOS window. The screen simply waits for the user to type a command.

COMMAND DRIVEN INTERFACES

To interact with a a command driven interface the most important piece of hardware we require is a keyboard.

We also tend to need the monitor for output.

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ADVANTAGES of COMMAND DRIVEN

INTERFACES Faster than using other interfaces

Uses less memory because there are no graphics

Works on computers with limited hardware and software resources

Experienced users can use this system faster than others.

Complex commands can be entered to customise the system for a particular user.

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DISADVANTAGES of COMMAND DRIVEN

INTERFACESPeople with limited knowledge of the commands find the interface confusing and hard to use.

Errors in commands can cause the operation to fail and can be very time consuming.

Any errors in typing will require the user to re-type the command. This is time consuming and frustrating.

Commands have to be learnt and this is difficult especially when there are hundreds of them

The interface is not attractive compared to a GUI interface.

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MENU

DRIVEN

INTERFACES

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MENU DRIVEN INTERFACES

• A Menu-Driven program is one that presents users with a list of choices and available options.

• Menu–Driven programs are usually considered ‘friendlier’ and easier to learn than programs with a command–line interface.

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MENU DRIVE

• Menu -Driven is a program that uses menus to present choices of command and available options. Menu –Driven programs are usually considered ‘friendlier’ and easier to learn than programs with command –line interface.

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Example of Menu- driven interface26

ADVANTAGES

• Free from typing errors, because user does not have to type commands.

• Easier to learn than a command driven interface

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DISADVANTAGES

• Several steps required to issue a command.

• Once user has learned the menu system it is bothersome to have to wait on the package to present the questions before command can be entered.

• Limited use of colours28

GRAPHICAL

USER

INTERFACES

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GRAPHICAL USER INTERFACES

• A graphical user interface is a type of user interface which allows people to interact with electronic devices such as computers, hand-held devices, gaming devices, household appliances and office equipment with images rather than text commands.

• The main interfacing device for a GUI is the mouse.

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GRAPHICAL USER INTERFACES

• A graphical user interface is sometimes regarded as a WIMP interface. It has

– Windows– Icons– Mouse usage and– uses a Pointer

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ADVANTAGES OF GUI

•Easier to learn and use; user friendliness•Icons/symbols are easier to recognize and provide the user with a context•Fewer command error•Reduce typing

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DISADVANTAGES OF GUI

•May consume more screen space•For programmers the design of Graphical User Interface is more complex•Increased use of computer memory can lead to slower processing•Takes up more disk space.•Takes up more memory

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SOFTWARES

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The GUI is more appropriate for children and also for inexperienced computer users.

Programmers and other highly technical professionals prefer the command driven interface

Miscellaneous

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In addition to knowing the interfaces there are some other terms we should know.

ICON

• A computer icon is a graphical symbol that represents a property, function, or entity.

• In computer applications, icons are used to quickly execute commands or open programs and documents.

• You access the functionality behind an icon by clicking or double-clicking it.

Examples of Icons

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PULL DOWN MENUS

• Also called a drop down menu

• A menu of commands or options that appears when you select an item with a mouse

• The item you select is generally at the top of the display screen and the menu appears just below it as if you had pulled it down

Example of Pull-Down Menu37

POP -UP MENUS

What is A Pop –Up Menu?

• A menu that is not visible until accessed. When accessed, this menu will open a new window and commonly be above all other screens on the display.

• Often used in dialog boxes to provide a list of mutually exclusive choices; a more compact choice than listing the items as radio buttons.

Examples of Pop –Up Menus38

Types of software interfaces include the Command Driven interface, the Graphical User Interface and the Menu Driven interface

Specialised hardware interfaces consist of Touch Screens, Sensors, Non-Visual Interfaces and Braille Keyboards.

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An interface has both hardware and software elements

THE ENDDone By: (Group 3)

Shaneka EarlEdwina Henry

Daneile MathesonBrittany Clarke

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