4 - Data Representation Flashcards
Note: Look at WJEC Knowledge organiser for diagrams of the topics discussed. Link: https://drive.google.com/file/d/1bJeC2zswFSr29Z2BDrv8i2GYk_qtPnhD/view
What is Denary?
Denary is a base 10 numbering system, its the most common form of numbering system used in everyday
What is Binary?
Binary is a base 2 number system. Uses digits 0 and 1 only
What is Hexidecimal?
Hexidecimal is a base 16 number system.
Uses digits0 – 9 and characters A(10), B(11), C(12),
D(13), E(14) and F(15)
The notation is used as shorthand for binary numbers to avoid errors
Explain Binary Overflow
When the number is too large to be stored by the register, the left most bit cannot be stored and therefore cannot be counted.
How do you shift Binary digits left?
To shift binary digits left by a certain amount of places (x), you could either move all the digits left x amount of times. Or you could times it by 2 to the power of x
How do you shift Binary digits right?
To shift binary digits right by a certain amount of places (x), you could either move all the digits right x amount of times. Or you could divide it by 2 to the power of x
What is a Pixel?
A Pixel is a small coloured dot on a computer
display (short for picture elements).
What is a Bitmap?
Bitmaps are images are stored as an array of pixels.
What are Vectors?
Vectors are images that do not store the data by
pixels, but are a set of instructions for
drawing a geometric shape.
What is the Sample Rate?
The Sample Rate is the number of audio samples captured every second
What is the Bit rate?
The Bit rate is the number of bits used per second of audio
What is the Bit depth?
The Bit depth is the number of bits available for each clip
What is Metadata?
Metadata is a set of data that describes and gives information about other data
How is a colour Bitmap stored?
A colour bitmap image is stored using a longer binary number that represents how much red, green and blue (RGB) is required in the colour of each pixel to produce different colours.
How is sound stored?
Sound is converted into a digital signal by a process called sampling. This is where hardware, such as a microphone, measures the level of sound many times per second and records this as binary digits.
Give 3 Examples of Metadata
Genre – the genre that the sound file belongs to
Date Created / Year – the date the graphic was taken
Location – the location where the graphic was taken
Size – the original size of the file
Dimensions
What is a Character?
A Character is a letter, digit, space, punctuation mark or various other keyboard symbols.
Define a Character Set
A Character set is a table that maps a character with a unique binary number.
Explain Data Structures
Data Structures are specific ways of organising
data within memory so it can be processed efficiently.
What is a Record?
A Record is a data structure of related data of different data types
What is a Primary Key?
A primary Key is a unique identifier for each record
What is an Array?
An array is a data structure that can hold a fixed number of data items, which must be of the same data type
What is an Integer?
An Integer is a whole number, postive or negative
What is a Real?
Reals are numbers including a fractions or decimal points
Explain what a boolean data type is
A boolean data type is either true or false
What is a String?
A String is a sequence of characters
What is Validation?
Validation ensures hat data entered is reasonable. For example a 30 character limit on a first name
