Data Handling Topic 1. Data Data is the raw material entered into a computer system. This raw...
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Transcript of Data Handling Topic 1. Data Data is the raw material entered into a computer system. This raw...
Data Handling
Topic 1
Data
InformationWhen data is given a structure and put into
context it becomes informationa word processed document that we can read
and understandA computer interprets and executes instructions
to process the data into informationEg:
Today + will + be + temperature + hot + a + 32 + day + a + with + degrees + of
Today will be a hot day with a temperature of 32 degrees
Classifying data as information is not always clear and absolute.
What is information to one person may be data to another person.
Information is a vital tool.
Organisations cannot exist without it’s data/information. ‘the more information the better’ – only if the
information is suitable, accurate, timely and reliable
Data Coding
AnalogAnalog data is represented by using continuous
signals [wave form] that vary in strength and quality.
Eg: an analog clockBecause the movement is continuous, a measurement may be taken at any time.
Eg: Human speechPeople combine words into sentences which are continuous
DigitalComputers are digital
They recognize two states: off and on
Digital data is represented using discreet measurements in the form of digits/numbers – 0 & 1
The two digits [0 & 1] represent these two states 0 represents the electronic state of off 1 represents the electronic state of on
Eg: a digital clock Shows the time as a certain number of hours and minutes. Time does not change continuously, but in a series of steps, jumping from second to second and minute to minute.
BinaryA digit is a single place that can hold numerical
values between 0 and 9 - base-10 number system – known as decimal number system.
Computers happen to operate using the base-2 number system, also known as the binary number system.
Why base-2?Because it makes it a lot easier to perform with current electronic technology.
BinaryTechnology uses a binary system that has just two
unique digits – 0 & 1
Each digit is called a bit (Binary digIT)
A bit is the smallest unit of data that a computer can process
On it’s own a bit is not very informative
When 8 bits are grouped together as a unit, they form a byte.
A byte provides enough different combinationsof 0s and 1s to represent 256 individualcharacters.
Units of Measurement
Binary How do you figure out what the value of a binary number
is? You do it in the same way you would for a decimal number, but you use a base of 2 instead of a base of 10.
Decimal [6,357]: (6 * 10^3) + (3 * 10^2) + (5 * 10^1) + (7 * 10^0) = 6000
+ 300 + 50 + 7 = 6357
Binary number [11]: (1 * 2^3) + (0 * 2^2) + (1 * 2^1) + (1 * 2^0) = 8 + 0 + 2
+ 1 = 11
You can see that in binary numbers, each bit holds the value of increasing powers of 2.
Convert binary to decimal
Convert decimal to binary
Data Types
Data Types
NumericTextHypertextAudiovisualPhysical
Numeric
Consists of numbers and decimal points.
Both arithmetic operations (+ - * /) and logical operations (and, or, if, not) are performed on numeric data.
Numbers can be used for calculations as well as sorted and compared to each other.
A common file extension for numeric data include:
.xls (spreadsheet)
TextCan contain any combination of letters, numbers and
special characters.
Sometimes textual data is known as alphanumeric data.
Text is organised into words, sentences and paragraphs.
Some common file extensions for text include:.doc (document)
.txt (text)
.rtf (rich text format)
Essays, reports, letters, emails are examples of textual data.
HypertextText displayed on a computer or other electronic
device with references (hyperlinks) to other text that the reader/user can immediately access, usually by a mouse click
Some file extensions for hypertext include:.html
.htm
AudiovisualVarious forms of data that we can hear or
see
Data takes the form of graphs, drawings, photographs, video sequences and sound.
Audiovisual - graphicsThere are two types of graphics
Bitmapped graphics Each image is a pattern or map of tightly packed
dots (ie bits) Each dot [a pixel – picture element] has a
separate memory position that is represented by a colour or shade of grey
when you enlarge a bitmapped graphic, youenlarge each pixel creating a staircase pattern called aliasing or “pixelated” e.g. photographs
Most images on your computer are composed of bitmaps
Vector graphics Not made up of a grid of pixels Allows continuous lines to be drawn comprised of paths which are
defined by a start and end point Graphics are stored as mathematical formulas These graphics can be scaled to a large size and not lose any image
quality
Audiovisual - graphicsCommon bitmap file extensions are:
.bmp - bitmap
.jpeg- Joint Photographic Experts Group
.gif - Graphics Interchange Format
.tif - Tagged Image File
Common vector file extensions are:.ai – Adobe Illustrator.eps – Encapsulated PostScript file.svg – Scalable Vector Graphics file.drw – Drawing file
Audiovisual - audioAn electrical representation of sound
which can be transmitted or reproduced
Common file extensions include:.mp3.wav.midi
Audiovisual Video and Animation
VideoThe technology of electronically capturing,
recording, processing, storing, transmitting and reconstructing a sequence of still images representing scenes in motion
AnimationThe rapid display of a sequence of images of 2-D
or 3-D artwork or model positions in order to create an illusion of movement.
Common file formats for video include: .mpg, .mov
Common file formats for animation include: .swf, .gif
PhysicalCaptured from the environment.
Light, temperature and pressure
The temperature of a room may be controlled by a computerA thermostat is set to sense the air
temperature. When the temperature exceeds a specified level, a cooling system is turned on. The warmth of the air is used as physical data input into a thermostat to regulate room temperature.