Ict - computers Flashcards
Purpose of a computer
- input data
- store data
- process data
- store data
- output data
CPU
Central Processing Unit
What is the function of the CPU?
To perform all processing of the computer
Hardware
Physical components of a computer system. Computers require hardware to exist
Two types of hardware
external and internal
software
something that you install onto your computer that has its own code.
The programs and applications that you run.
External Hardware
peripherals
Examples of external hardware
- a mouse,
- keyboard,
- microphone,
- camera,
- touchpad,
- scanner,
- USB flash drive or memory card
Input device
piece of hardware that is used to enter data into a computer
Two categories of input devices:
manual and automatic input devices
scanner
converts images or text on paper into a digital format that can be used by the computer
How does a scanner work?
- Shining a beam of light onto the surface of the object that you are scanning.
- This light is then reflected back onto a sensor that detects the colour of the light.
- This is then used to build up the digital image.
Advantages of scanners
- Produces high quality images
- Image can be included in electronic documents
- Digitised images can be enhanced by software
- Can convert old material into digital copies
Disadvantages of scanners
- can take up a lot of space
- Images can lose some quality when digitised
- Quality of final image is dependent on quality of original image
- Emotional value is taken away
How does a barcode reader work?
- Scan or ‘read’ the barcode by using a visible red light.
- The reflected light is translated into digital data that is interpreted by the computer to identify the product and price from the database.
OMR (Optical Mark Reader)
It detects the presence of your pencil mark by reflecting light onto it.
Less light is reflected where a mark has been made.
Advantages of OMR
- A fast method of inputting large amounts of data.
- Only one computer needed to collect and process the data
- more accurate than data being keyed in by a person
Disadvantages of OMR
- If the marks don’t fill the space completely, they may not be read correctly
- Not suitable for text input
- Prepared forms which will all be identical to one another. well designed
Optical Character Recognition (OCR)
used to scan text on a document or piece of paper into the computer.
The OCR software then examines the page and changes the letters into a form that can be edited or processed by a normal word processing package (WORD)
Advantages of OCR
- cheaper than paying someone to enter data manually
- faster than manual entry
- software can manipulate data
Disadvantages of OCR
- not 100% accurate
- documents needed to be checked and corrected
- if original document has a lot of mistakes, it will influence final product
output device
piece of hardware that is used to display or output data which has been processed or has been stored on the computer
Laser printers
- Laser printers are used in many workplaces because they are quiet.
- prints a large number of sheets quickly
- produce high quality documents.
Advantages of laser printers
- high quality printouts
- fast printouts
- quiet printouts
- cost per page is low
Disadvantages of laser printers
- expensive to buy
- toner is more expensive
- expensive to repair
- fairly bulky
Inkjet printer
- They operate by heating the ink as it flows through a set of tiny nozzles.
- The heating process = small droplet of ink to form.
- This is released as a single dot.
Advantages of Inkjet Printers
- cheap to buy
- compact
- cartridges cheap to replace
- faster than a dot-matrix
Disadvantages of Inkjet printers
- noisier than laser printers
- colour printing can be slow
- cost per page is more expensive
- ink will smudge
Plotters
- specialist type of printer
- draws high quality images on very large pieces of paper
- used by engineers, architects and map-makers
How does a plotter work?
- it draws images using a pen that can be lowered, raised and moved across the paper to form continuous lines
- pen is moved around the paper by computer controlled motors
Operating System (OS)
core software that allows a computer to run as an useful device
Functions of OS
- Providing a user interface
- Managing the computer’s memory
- Managing the hardware
User Interface (UI)
The part of computer application through which a user interacts with a program.
Wimp or Graphical User Interface interface (GIU)
makes use of pictures, graphics and icons.
Windows - a rectangular area on the screen where the commonly used applications run
Icons - a picture or symbol which is used to represent a software application or hardware device
Menus - a list of options from which the user can choose what they require
Pointers - a symbol such as an arrow which moves around the screen as you move your mouse. Helps you to select objects.
