WHAT IS A COMPUTER?ICAICT101A

Operate a Personal Computer

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What is a Computer?

A computer is an electronic device that allows you to process and store data (information)…

Data is entered into the computer by using a variety of input devices :keyboard, scanner, mouse

Once entered, the data can then be processed eg to produce a report

The information can then be made available on a variety of output devices :computer screen, printer

Data can also be stored saved for future use

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Hardware

Hardware refers to the physical components of the computer – the things you can actually touch

Keyboard Monitor (screen) Mouse Speakers Printer

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Central Processing Unit (CPU)

The Central Processing Unit (CPU) is a chip or the “brain” of the computer and directs activities on the computer.

Its job is to receive and carry out instructions millions of times every second.

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Peripheral Devices

A peripheral device is a device that is attached to the computer by port or wireless.

It usually performs some input or output task, eg printer, scanner, speakers, internal/external DVD or hard drive.

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Attaching Peripheral Devices

Peripheral devices are attached to the computer via ports located at the back or front of the computer, or by wireless technology.

The most common type of physical port used today is a USB port.

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Input/Output Devices

Computer devices are classed as either input, output or sometimes even bothI/O (input/output).

Input devices get data into thecomputer, eg mouse, keyboard, scanner.

Output devices get data out of thecomputer, eg monitor, printer, speakers.

Devices such as USB drives, DVD burners are both input and output.

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Software

Software refers to the instructions or programs that make the computer work.You can’t actually touch the software.

Software tells the computer what to do.

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Two types of Software

Operating (system) Windows 7 Windows Vista Windows XP Linux

Application (program) Microsoft Office:

Word Excel Outlook PowerPoint

Accounting, eg MYOB

Games

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Why do we save data?

If the computer is turned off or if there is a power failure, all the data that is stored in Random Access Memory (RAM) is lost!

If you want to keep data to use again later you must save it.

You can save it to a permanent storage device such as the hard disk (C:) a USB, a DVD/CD or an external hard drive.

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Permanent Storage

Computers come with a built-in DVD burner and hard disk drive. These storage devices allow you to save data as a file for future use.

The hard disk is a fixed disk installed inside the computer. Most hard disks store between250gb and 4tb.

DVD and CD drives store datadigitally and can hold as much as 17gb.

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Permanent Storage

USB / flash drives are small, portable devices that are good for storing data or transferring data between different computers. They plug into a USB port and range in capacity from 1gb to 64gb.

External hard drives plug into a USB port and are good for keeping backup copies of data. The range in capacity from 500gb to 16tb.

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Computer Memory

Storage capacity is measured in bytes. 1 byte equals approximately 1 typed character.

Kilobyte (kb) approximately 1024 bytes Megabyte (mb) approximately 1 million

bytes Gigabyte (gb) approximately 1,000

million bytes Terabyte (tb) approximately 1 trillion

bytes (1,000 gb)

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Working with Files

A computer file is an electronic document. When a file is saved it needs to be correctly named. Every file name ends with a dot(.) followed

by an extension of 3 or 4 letters. Windows operating system automatically

puts the correct extension on a file for you. You must never use a dot (.) in a filename.

A file saved in MS Word will have an extension of .docx, Excel .xlsx, PowerPoint .pptx. A picture file is likely to have an extension of .jpg.

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Working with Files

After a while you will become familiar with the various file extensions and recognise what program a file was created in.

Files also have different icons to help identify the program they were created in:

Filenames can include upper and lower case characters and/or numbers, but cannot include most symbols, eg / \ : * ? “ ” < >

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System Files

System files are used by the computer and should never be renamed, deleted or altered.

Some system file extensions include:.com.exe.bat.sys.dll.cfg