Fundamentals of data representation Flashcards
What is a bit?
A Binary Digit. The smallest digit in the binary system. 0 or 1
What is a nibble?
Four bits
What is a byte?
Eight bits
What is a kiloByte?
1000X bytes
What is a megaByte?
1000X kiloBytes
What is a gigaByte?
1000X megaBytes
What is a TeraByte?
1000X gigaBytes
What is a binary shift left?
Multiplies a binary number by 2 for each shift left
What is a binary shift right?
Divides a binary number by 2 for each shift right
What is ASCII?
A 7-bit set of codes that allows 128 different characters. That is enough for every upper-case letter,
lower-case letter, digit and punctuation mark on most keyboards
What does Unicode use?
Between 8 and 32 bits per character, which can
contain many millions of characters. It is commonly used across the internet. The first 128 characters in UNICODE are the same as the 128 characters in ASCII
What are the cons of unicode?
As it is larger than ASCII, it takes up more storage space and network bandwidth
What is an analogue?
Sound waves that are continuous waves that must be converted for a
computer to process
What is a sample?
A measurement taken from an analogue sound wave at a point in time
What is sample rate?
The total number of samples taken in 1 second, measured in the unit of Hertz (Hz)
What is sample resolution?
The number of bits used to represent the value of a sample
What is a pixel?
Smallest, most addressable part of an image
What is bitmap?
A two dimensional array of binary data representing the values of pixels in an image
What is image resolution?
The total pixels in an image which is expressed as a calculation of the pixels in the format of width x height
What is colour depth?
The number of bits used to store each pixel. The more bits used to represent each pixel, the greater the total colour combinations will exist for the image
What is data compression?
The process of reducing the size of data so that
it takes up less storage space. Compression can use either lossless or lossy techniques
What happens when using lossy compression?
We can often receive a very small version of the original, however we cannot get back to the original data exactly as some data is lost in the process
What happens when using lossless compression?
We may receive a smaller piece of data than the original data, however we can always recover the original data – no data is lost
What is run length encoding?
A lossless data compression algorithm that converts consecutive identical values into a code consisting of the character
and a number marking the length of the run of the character
What is huffman encoding?
A lossless data compression algorithm which allows a computer to compress and decompress a string based
upon how often characters are used
