Units of Memory – Bit
- Byte
- Kilobyte (kB)
- Megabyte (MB)
- Gigabyte (GB)
- Terabyte (TB)
Input devices – hardware used to input data
Examples: Keyboard – used to enter letters and numbers, and used for shortcuts.
Mouse – used to point and click.
Output devices – hardware that is used to output data
Examples: speaker – if you need sound,
Printer – if you need to produce paper-based output
Backing Storage – USB ports – for memory sticks
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Hard Drives – on desktop computers
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Optical Drives – a disk drive that uses laser light or electromagnetic waves to read data from optical media like CDs and DVDs.
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Flash memory – non-volatile memory used in electronic devices like MP3 players and digital cameras
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Storage Media – Virtual memory
- The Operating System
The Operating System controls the systems hardware and software. It provides user interfaces that allow users to interact with the computer.
Graphical User Interface (GUI) – a way for users to interact with the computer using images, graphics and icons.
GUIs are made up of WIMP:
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Windows – a rectangular area on the screen where the commonly used applications run.
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Icons – a picture or symbol, which is used to represent a software application or hardware device.
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Menus – a list of options, which the user can choose what they require.
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Pointers – a symbol, like an arrow, which moves around the screen as you move your mouse. It helps you select objects.
Menu Interface – lets you interact with a computer or device by working your way through a series of screens or menus.
- The user is presented with a menu, you make a choice and then the next menu appears on the screen.
- It can also be verbal rather than visual.
- Most of the software we use have menu interface.
- Examples: ATMs, mobile phones, telephone customer services etc.
Command Line Interface (CLI) – allows the user to interact directly with the computer system by typing in commands (instructions) onto the screen.
- The user can’t just type in any kind of instruction; the computer will only react to a definite set of words.
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E.g. in DOS (Disk Operating System) you could type in: copy c:/item.txtd
- Example: DOS
File and Folder Organization
Computers store files in folders. A folder can contain other folders called subfolders.
File path – an address that shows where the file is stored.
File Extension – shows what type of file it is.
File names – avoid special characters: /?<>*%:””.
- keep file names short
- don’t forget a file extension.
- Using computer systems
Identifying ICT problems and solving errors
Freeze – Ctrl, Alt and Del can close down the package that is causing the freeze to occur. Having less memory on a computer with lots of packages open makes a freeze more likely.
Error messages – sometimes error messages occur more on just one software package, so it may need to be reinstalled.
Storage space – if the storage space becomes too full it may slow he computer down.
Printers – Paper jams are the most common errors, if paper isn’t loaded correctly.
- Input and Output devices
Input devices
Keyboards – the user can press a key and input information.
Mouse – the user can click objects and input information.
Microphones – the user can speak into a computer, inputting information.
Magnetic stripes – when swiped through a reader, they input information.
Sensors – motion sensors on game consoles help input information to play a game.
Bar-code reader – can be scanned and information can be recorded on a computer.
OMR (Optical Mark Recognition) – multiple choice sheets that scanned into a computer.
OCR (Optical Character Recognition) – used to convert paper-based text into a computer document.
Output devices
Monitor – the image on the screen that the user looks at.
Printer – prints out text on paper.
Speakers – produce sound from the computer.
Plotters – (like a printer but it’s used to draw up blueprints and technical plans)
- Storage devices
- Communication Networks
Network – a group of computers linked together to allow them to share resources and information.
Networked computers can share:
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hardware – printer
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software – they will be able to load up the same programs.
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data – they can load up the same files
Two types of network: Local Area Network (LAN) – covers a small area like one gggggggggggggggggggggggggggggggggggggggggbuilding e.g. a school or a gggggggggggggggggggggggggggggggggggggggg college
Wide Area Network (WAN) – covers a large geographical area ggggggggggggggggggggggggggggggggggggggggge.g. companies with offices gggggggggggggggggggggggggggggggggggggggggacross the world
Computer System
To process data
Input – data entered into the system
E.g. Memory stick
Output – the action that occurs after the input has been processed.
E.g. Printer
Processing – turning the input into a useful form
E.g. Microsoft word
Operating systems are needed in order to run application software
The differences between hardware and software
- Hardware is a physical device that you can touch.
- Software is program code that gives the computer instructions about how to operate. Computer programs are software.
- Hardware needs software in order to function.
- Hardware and software work together in computers and other devices that use microprocessors.
Units of memory
- 1 MB is just over 1,000 KB
- 1 GB is just over 1,000 MB
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1 TB is just over 1,000 GB
Volatile memory – memory that is lost when the computer is turned off
Non-volatile memory – memory that isn’t lost when the power is turned off.
Input devices – anything that gives information to a computer like: speaking - microphones
Output devices – anything that gives out information from a computer like: paper - printer
* Data on files should be backed up just in case it is lost or stolen. *