# Computing

version from 2016-11-06 17:28

## Section 1

What is data?A set of recorded facts that have no meaning
What is information?Data after processing
Describe the denary/decimal number system.10 as the base. requiring 10 different numerals
Describe the binary number system.2 as the base. requiring 2 different numerals
Describe the hexadecimal number system.16 as the base. requiring 16 different numerals
Why do we need to use the binary number system in computer science?A computer switch can only be on or off.
Why is the hexadecimal number system used?it is just a more convenient symbol for four binary bits

## Section 2

What is a character set?A list of characters recognised by the computer hardware and software. Each character is represented by a number.
What is ASCII?American Standard Code for Information Interchange. It is the most common format for text files on the Internet. Each alphabetic, numeric, or special character is represented with a 7-bit binary number
What is unicode?International encoding standard. Each letter, digit, or symbol is assigned a unique numeric value

## Section 3

What is a truth table?Electronic circuits used in computers can be wired together to form logical calculations.
What are logic circuits?It is when logic gates are combined
What is Boolean algebra used for?It is used in computer programs. When these expression are evaluated, they give a Boolean logic output of either true or false

## Section 4

What is a bit?The smallest unit of data in a computer. Is a single binary digit, either 0 or 1
What is a byte?Eight binary digits long
What is a crumb?Two binary digits
What is a nibble?Four binary digits. Can be conveniently represented by one hexadecimal digit.

## Section 5

how are instructions coded as bit patterns?Instructions consists of an operator (The instruction) and an operand (the data)
How does a computer know if it is reading instructions or data?The first four bits is the operator and the last four bits is the operand
How is sound stored?Stored as a digital data file composed of a set of binary numbers
What is sound sampling?Sound sapling is the conversion of a sound wave (a continuous signal) to a sequence of samples
What does the term sampling rate mean?The number of samples taken per second from the analoge input
What does the term sampling resolution mean?The number of bits used to store each sample
What are digital images made up of?A series of pixels.
What is a pixel? The smallest element in a digital image
How many colours can be represented by 1 bit per pixel? Which colours are these?2^1 black and white
How many colours can be represented by 8 bits?2^8
How many colours can be represented by 16 bits?2^16
What is colour depth?The number of bits for each pixel
What is metadata?It is data about data. It gives details of image height, width and colour depth
What is resolution?is the number of dots per inch (DPI)