1 Data Representation Flashcards
Uses of the hexadeciaml system (4)
error codes
MAC addresses
IP address
HTML colour codes
What do the hex values of the error codes refer to
memory location of error
What is a MAC address
uniquely identifies each device on a network
How is a MAC address usually formatted?
6 groups of 2 hexadecimals
EG: NN - DD - NN - DD - NN - DD
First half of the MAC address identifies the?
manufacturer
Second half of the MAC address identifies the?
Serial number of the device
Define IP address
unique numerical identifier assigned to devices connected to the internet, identifying their location
What is IPv6
128 bits broken into 16 bit chunks by a hexadecimal number
Features of ASCII code (3)
Uses 7 bits to represent characters
limited to 128 characters it can represent
Can only represent the english language
Features of unicode (3)
Uses 16 bits to represent characters
Able to represent 65,536 characters
Can represent all languages in the world
Define sample resolution
number of bits used to record each measurement during sampling
Define sample rate
number of measurements taken per second
Define sampling
A task performed by the ADC to represent analouge sound wave into a digital format
what will using higher sample rate and larger sample resolution do to the orignal source (2)
more faithful representatiojn
larger file size
Define pixel
smallest identifiable piece of an image
What is a digital image
a series of pixels that are converted
to binary, which is processed by a computer
Define image resolution
the number of pixels in an image
Define colour depth
number of bits used to represent each colour
What will increasing image resolution and colour depth do to the file? (2)
Better detail, more colours represented (higher qualiy)
larger file size
How to calculate file size of an image
image resolution x colour depth
How to calculate file size of sound
sample rate x sample resolution x length of track
Write different units of data storage from smallest largest
bit (1 bit)
nibble (4 bits)
byte (8 bits)
kibibyte (1024 bytes)
mebibyte (1024 kibibytes)
gibibyte (1024 mebibytes)
tebibyte (1024 gibibytes)
pebibyte (1024 tebibytes)
exbibyte (1024 pebibytes)
Reasons for data compression (3)
To save storage space devices
reduced file size reduces costs
reduce time taken to stream
What are the two types of file compression (2)
Lossless file compression
Lossy file compression
Features of lossy file compression (3)
alogirthm eliminates unnecessary data from file
original file cannot be reconstructed once it is compressed
Compression results in some loss of detail
Examples of lossy file compression (3)
MP3 - Used for playing music
MP4 - Allows storage of multimedia files
JPEG - lossy file compression algorithm used for images
Features of lossless file compression (2)
compression algorithm is used, repeated patterns in the file are identified and indexed
original uncompressed file can be reconstructed
Example of lossless file compression
RLE
Features of RLE
indentifies and indexes repeating patterns (string of adjacent, identical data)
