Data Representation Flashcards
How many GiB in a TiB?
1024 GiB
How many MiB in a GiB?
1024 MiB
What are the uses of hexadecimal?
Colour values in photo editing software
MAC addresses
IPv6 addresses
Unicode
What is an overflow error?
A computer or a device has a predefined limit that it can represent or store (e.g. 32 bits).
Once a values falls outside this limit, an overflow error occurs
How to convert using a Two’s Complement Signed Integer?
Flip the bits and add 1
What is a character set?
Consists of all the letters, numbers and special characters that can be recognised by a computer system.
How many characters/bits does the ASCII character set use?
128 characters / 7 bits
How many characters/bits does the Extended ASCII character set use?
256 characters / 8 bits
How many characters/bits does the Unicode character set use?
65,356 characters / 16 bits
What is sample rate measured in?
Frequency in Hertz
What is the sample rate?
How often the height is recorded (x-axis)
What is the sample resolution?
The accuracy to which the height is recorded (y-axis)
What is sample resolution “measured” in?
Bit depth
How to calculate file size of a sound file in bytes?
(Sample rate x Sample frequency x Length) / 8
What is the colour depth of an image?
The number of bits required to represent the number of colours in the image
What is the image resolution of an image?
The number of pixels in the image (i.e. the area of the image ~ b x h)
What is metadata?
The information that allows us to recreate the image on the screen
How to calculate the file size of an image file in bytes?
(Image resolution x Colour depth) /8
What file formats use Lossy compression?
JPG, MP3, MPG
What are the advantages of Lossy compression?
Biggest reduction in file size
Least transmission time
Reduces Internet traffic and collisions
What are the disadvantages of Lossy compression?
Detail is permanently lost by reducing the colour depth, resolution or rate
When would Lossy compression be used?
Music streaming
Online images and video
Image libraries on devices or in the cloud
What file formats use Lossless compression?
TIF, PDF, GIF, PNG, ZIP
What are the advantages of Lossless compression?
Original quality is preserved / no information or data is lost
What are the disadvantages of Lossless compression?
Less significant reduction in file size
When would Lossless compression be used?
Text documents
Electronic books
High resolution documents
