digital data Flashcards
what is data and information?
data is raw facts and figures/meaningless/haven’t been processed
information has meaning added/has been processed
put these in correct order = smallest to largest
gigabyte, bit, byte, megabyte, nibble, terabyte, kilobyte
bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte
what’s the difference between integer and real numeric numbers?
integer is a whole number
real has a decimal place
what is date and time as a data type?
you can choose how to format the date/time
long, medium or short date/time
What’s a character
A letter, symbol or number
What’s a string
A ‘text’ or ‘alphanumeric’
eg. A name = Sue Black
What is a Boolean?
True/false
What is a pixel?
The smallest unit of an image
‘Picture’ and ‘element’
What is colour depth?
N-bits per pixel
eg. You can have 2n different colours! 22^ = 4
What is the resolution of an image?
what does it tell us?
The number of pixels per inch/cm
it tells us the quality of an image
What does a higher resolution lead too?
Higher overall image loading
Higher processing times
Higher overall image file transfer times
bitmap graphics (or raster graphics) have…
A grid of tiny pixels Can edit individual pixels High-quality images Image can blur if stretched Takes up loads of storage Takes a long time to load
vector graphics have…
Stores details about individual components
Made up of objects
Quality doesn’t depend on resolution
Can be resized without loss of quality
Lack of a need to store individual pixels
What’s the difference between streaming and buffering?
- Streaming allows a video to be viewed straight away without having to wait for the full video to be downloaded
- Buffering holds the downloaded segments that have not yet been played
What is Sample Rate
• The quantity of samples taken per second
Measured in Hertz (Hz)
• Sample Rate higher = better quality
• Sample rate lower = reduces quality
• requires more storage space and more CPU time/processing power
What is Bit Depth
- number of bits that is allocated per sample taken
* higher quality sound requires a higher bit depth
What is Bit Rate?
• number of bits required to store 1second of sound
bits per second (bps) or kilobits per second (Kbps)
• bit depth x sample rate = bit rate
• a high quality sound indicates a high quality sound
What is Analogue
The original sound
What does an Analogue to digital converter do?
It will sample a sound wave at regular time intervals
Examples of image files
JPEG, BMP, tiff, png, Pict and gif
Examples of text files
Txt, cvs, rtf and pdf
Examples of sound files
wav, mp3, wma and midi
Examples of video files
MPEG, mp4 and avi
Data compression is…
Converting digital data to as small a size as possible while still maintaining the quality of the data
