2.1.9 Define the terms: bit, byte, binary, decimal, hexadecimal.
2.1.10 Outline the way in which data is represented in the computer.
Main memory is consists of a collection of storage locations, each with a unique identifier, called an address.
Data is transferred to and from memory in groups of bits called words.
A word can be a group of 8 bits, 16 bits, 32 bits, or 64 bits (and growing)
If the word is 8 bits, it is referred to as a byte
The term "byte" is so common in computer science that sometimes a 1bit words is referred to as a 2-byte word, or a 32-bit word is referred to as a 4-byte word.
Storage capacities and file sizes are measured (from smallest to largest) in:
bit: a unit of information expressed as either a 0 or 1 in binary notation.
Byte: a unit of memory size comprised of a group of binary digits or bits (usually eight) operated on as a unit.
Kilobyte (KB): a unit of memory or data equal to 1,024 (210) bytes.
Megabyte (MB): a unit of information equal to 220 bytes or, loosely, one million bytes.
Gigabyte (GB): a unit of information equal to one billion (109) or, strictly, 230 bytes.
Terabyte (TB): a unit of information equal to one million million (1012) or strictly, 240 bytes.
Petabyte (PB): 250 bytes; 1024 terabytes, or a million gigabytes.
8 bits
1024 bytes
1024 kilobytes
1024 megabytes
1024 gigabytes
1 byte
1 kilobyte
1 megabyte
1 gigabyte
1 terabyte
Is the most commonly used number system.
It uses 10 digits and these are the numeric values from 0 to 9.
Also known as decimal or base 10.
All denary numbers have a binary equivalent and it is possible to convert between denary and binary.
A number system used by computer systems to process and store information
It uses two digits; 0 and 1
Also known as base 2
The digits 0 and 1 used binary reflect the on and off states of a transistor.
One binary digit (bit), is the smallest unit of data in computing, it can have a value of only 0 or 1.
All software, music, documents and any other information that is processed by a computer, is also stored using binary.
denary number 39 as an 8-bit binary number is 00100111
denary number 48 as an 8-bit binary number is 00110000
2^2
128
0
2^6
64
0
2^5
32
1
2^4
16
0
2^3
8
0
2^2
4
1
2^1
2
1
2^0
1
1
Hexadecimal (or hex) system is a base 16 system used to simplify how binary is represented.
It uses 16 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. Which A is 10 in decimal, B is 11... and F is 15.
Every digit can be converted into a 4-bit binary value. Eg. F is 15 in decimal and 1111 in binary
Is translated into binary for computer use. e.g. color references, assembly language programs, error messages, etc.
A color is split into three components
The three components are Red, Green and Blue (RGB);
an 8-bit color graphics - a method of storing image information in a computer's memory or in an image file, such that each pixel is represented by one 8-bit/byte
The maximum number of colors that can be displayed at any one time is 256 or 2^8
Each component is assigned a certain number of bytes;