Difference between hardware and software
Hardware: a physical device, something that can be touched and seen.
Software: programs and code - cannot be physically seen or touched; only the results of running the software can be seen.
- enabling one piece of hardware to work with another and enabling data to be transferrred from one package to another.
- If you have two different systems there could be incompatibility in the hardware and software.
- The negative impacts of this, are as follows;
* No communication between systems/miscommunication between systems leading to incorrect data being passed.
* New equipment having to be purchased to bridge the gap.
* The cost of training staff on the systems.
* Lack of technical support on the systems.
Specialist software devices
- The most common specialist software aid for the visually impaired is a screen reader.
- This is a program that reads out a computer display.
- The screen reader may output information in Braille, use voice output, or use other audio signals to indicate graphics on the screen.
Other tools that can be useful include:
- Auditory feedback - this plays sounds in response to user activity, for example noises for key presses, opening windows and menus and deleting files. This is useful as it confirms the action.
- Screen magnifier - a utility that can zoom in on portions of the screen to make it easier to view information on computer monitors.
- Predictive text - this suggest the required word as the letters are typed so the user does not have to type the whole word.
- Sticky keys - these are useful for those people that find it difficult to hold down more than one key at a time. Sticky keys allow a key to be pressed once and the system to act as if it was being continually pressed. It allows combinations involving the Ctrl, Alt or Shift keys, by pressing only one key at a time.
Types of software
Software: computer programs that provide the instructions that enable the computer hardware to work.
- Controls the allocation and usage of hardware resources such as memory, central processing unit (CPU) time, hard disk space, and peripheral devices.
- It performs basic data management tasks such as recognising input from the keyboard, sending output to the display screen, and keeping track of files and directories on the hard disk.
- The means by which the user can interact with the application or operating system.
- Menu - an on-screen list of options.
- Form - an on-screen space for you to type.
- Command line - a space to type instructions.
- Natural language - a voiced-based interface.
Their use will depend on the context.
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* These are small programs that assist in the monitoring and maintaining of the computer system.
* There is a blurring between the boundaries of operating systems and utilities, wiht many utilites being bundled with operating systems.
- Printer montioring software
- Virus checkers
- File compression software
* These programs that allow the computer to be used to solve particular taks for the end user. Application software includes programs such as;
Word processors, Spreadsheets, Databases, Communications (email) and Graphics Packages
Input, Output and Storage Devices
- A piece of hardware that gets information into a computer.
- Examples include; keyboard, concept keyboard, touch screen, microphone, scanner mouse and digital camera.
- There are many different types of scanner, for example; bar code, magnetic and flatbed.
- A piece of hardware that gets information out of the computer and displays it to the end user.
- Examples include printers, speakers, montiors and LEDs.
- There are many different types of printer, for examples laser, inkjet and dot matrix.
This is any device that stores data.
Examples inclue ROM, RAM, hard drive, as well as portable devices such as external hard drive, CD-R/W and USB memory stick.
Specialist hardware devices
The two main groups of physically disabled people who require special devices to use a computer are visually impaired and motor impaired.
People who have a loss of vision - it may be total loss of vision in one or both eyes or partial loss.
- Braille Keyboard - a keyboard with Braille dots on the keys
- Microphone - an iput device for voice recognition.
- Loudspeaker - an output device for hearing signals and text read out.
- Screen magnifier - a magnifying glass that fits on top of the screen and enlarges parts of it.
- Braille printer - an impact printer that can create Braille on a page.
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This is a loss of or limitation of function in muscle control or movement or a limitation in mobility. This can include hands that are too large or small for a keyboard, shakiness, arthritis, paralysis and a loss of limb(s).
- Mouth stick - a stick for inputting controlled with the mouth.
- Puff-**** switch - a tube placed in the mouth and blown/****ed through.
- Tongue-activated joystick - placed in the outh and manipulated with the tongue.
- Eye typer - a device that fits onto the muscles around the eye and when the ey is moved a pointer on the screen moves.
- Foot mouse - a mouse that is controlled by the foot. Used by those who cannot use their hands for whatever reason.
A user interface is the method by which the user communicates with the computer.
- This is where the user is presented with a command prompt. The commands are typed into the computer.
- If the interface is only command-based, it takes up less memory and this has the effect of running the commands faster.
- A large number of commands have switches. These are parameters added to the end of the main command which add functionality.
- Command-based systems are for use by expert users with good understanding of the commands they are using.
- They are useful for running commands which cannot be accessed from a menu or form.
- A limited area on screen with boxes to fill in.
- It has labels to help the user and spaces to enter data such as drop down boxes, open text or option buttons.
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- Forms can guide the user through entering the relevant information in a structured manner.
- They can include the default options for the user and give context-based assistance.
- The data entry boxes can also be validated.
- Another type of interface is the dialogue interface.
- This asks questions and requires a response before continuing.
- Error messagesthat appear are part of a dialogue interface.
- Window, icons, menus and pointer is an interface that contains a rectangular are that can old an application or icons.
- Icons are graphic symbols that denote a program, command, file or a concept.
- A menu is a series of related items that can be selected.
- A pointer is an arrow on screen that mirrors the movement of the hand and can be used to select icons and windows.
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- A series of related items that can be selected.
- They are either pop-up or pull-down. They can be structured.
- Menus can be cascaded, that is one menu leads to another menu.
- Items on menus can appear faded to show they cannot be used in a particular context.
- Menus are useful where there is a limited set of commands that can be used in a specific situtation.
- Each menu can have a keyboard shortcut which makes it work with a variety of input devices.
- These allow the users to use their own language to communicate with the computer.
- It does not require any specific commands.
- There are two main types of natural language interface:
- spoken - typified by voice recognition software which allows you to speak into a word processor.
- Written natural language interfaces include Microsoft Help and Ask.com.
- PDAs (Personal Digital Assistants) can include software that recognises handwriting.