Topic 2 Flashcards
Pneumonic for names of data sizes
By numerous boats, kill many gay, trans people
How much is a bit?
A singlar the binary digit
How much is a nibble?
Four bits
How much is a kilobyte?
1000 bytes
How many kilobytes in a megabyte?
1000
How many megabytes in a gigabyte?
1000
How many gigabytes in a terabyte?
1000
How many terabytes in a petabyte?
1000
What is an overflow error?
When a calculation has more than eight bits so causes an overflow
What happens to a Binary number one shifted left
Doubles
What happens to a binary number when it shifts
It divides by two
Which is the first number to turn into a letter in hexa decimal
10 and it is a
How to convert binary into hex
Split the byte into nibbles ( 8 into two 4s)
Convert nibbles into hex
What is ASCII
The most commonly used character set it consists of 128 characters including letters numbers and symbols and use a 7 bit binary code to identify each character
What is Unicode
Another character set that try’s to cover ever possible symbol or letter that could be written it covers all major languages
Formula for file size in bits for characters
Number of bits per character x number of characters
How are images stored
In a series of pixels represented by binary
How to increase number of colours in a photos?
Make a greater range of number of bits
What is colour depth
Number of bits used for each pixel
Formula for working out total number of colours in a photo
2^n where n = colour depth
What is image resolution
The number of pixels in an image
Formula for resolution
Width x height
Formula to work out file size of an image
Image resolution x colour depth
Or
Width x height x colour depth
What is metadata
The information stored in an image file which helps the computer recreate the image on screen from the binary data
Example of meta data
File format
Height
Width
Colour depth
Resolution
What is analogue
Data that is continuos and doesn’t not have fixed certain values
What is digital data
Data that is stored as non continuous and it sorted on certain fixed values
Which part of the computer converts data from analogue to digital
The analogue to digital converter
What is sample rate
The amount of data taken per second
What happens if the sample data is increased
Quality of audio increases
What is bit depth in sound
The number of bit available for each sound
How to calculate size of sound file
Sample rate x bit depth x length
What would happen if sample depth was increased
Quieter sound would be picked up
What is compression
Make file smaller while trying to make the compressed file as true to the original.
Benefits of compression
Faster download
Takes up less storage space
Web pages load faster
What is lossy compression
Compression where data is permanently removed from the file
What is lossless compression
Makes the file smaller by temporarily removing data to store the file and then restores it when opened
Pros of lossy
Greatly reduces file
Take up less bandwidth
Commonly used
Cons if lossy
Looses data
Can’t be used on text or software as these files need to have all the data
Worse quality
Pros of lossy
No reduction in qualified
Can be turned back ro original
Can be used on text and software
Cons of lossless compression
Only slight reduction in size compared to lossy
Example of lossy files
MP3
AAC
JPEG
Examples of lossless files
FLAC
TIFF
PNG
