1.2 Memory & Storage - An Introduction to Binary, Slides of Computer science

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Starter:

• What numbers is it

made from?

• How many states does

it control?

Memory & Storage: Lesson 4

An Introduction to Binary

Learning Outcomes:

1. Understand that data needs to be converted into a binary format to be processed by a computer 2. Convert positive denary whole numbers (0-255) into 8-bit binary numbers and vice versa

Memory & Storage: Lesson 4

An Introduction to Binary

Memory & Storage: Lesson 4 Binary Number System

• Computers use a binary number system consisting of only 0s and 1s
• Everything that a computer needs to process must be converted into a binary format
• This format is used for storing numbers, text, images, sound and program instructions

Memory & Storage: Lesson 4 Creating a circuit Computers comprise billions of switches to turn voltage on and off

Memory & Storage: Lesson 4 Bits and Bytes 1 bit = a single 0 or 1 1 byte = 8 bits = 1 character of text (A nibble = 4 bits or half a byte ) 1 KB = 1000 bytes 1 MB = 1000 KB or 1000x1000 bytes 1 GB = 1000 MB 1 TB = 1000 GB How many TB in a Petabyte?

Memory & Storage: Lesson 4 Binary Representation Number of Switches (Bits) Possible combinations or states 1 2 2 4 3 4 5 6 7 8

Memory & Storage: Lesson 4 Numbers with the Denary System Thousands, Hundreds, Tens and Units 1000 100 10 0 2 7 0 3 2x1000 + 7x100 + 0x10 + 3x1 = 2703

Memory & Storage: Lesson 4 Binary works in exactly the same way 128 64 32 16 8 4 2 1 1 0 0 1 0 1 1 0 1x128 + 1x16 + 1x4 + 1x2 =?

Memory & Storage: Lesson 4 Most and Least significant bit

• The most significant bit (MSB) is the bit with the largest value
  • This is the bit that is furthest to the left
• The least significant bit (LSB) is the bit with the smallest value
  • This is the bit that is furthest to the right 128 64 32 16 8 4 2 1 1 0 0 1 1 1 0 1

Memory & Storage: Lesson 4 Representing values

• Consider the same byte value 0011 1001
  • This is represented in denary as 57
  • As an electrical circuit this could be represented as: 0 0 1 1 1 0 0 1

Memory & Storage: Lesson 4 Denary to binary

• Convert 28 to binary: Method
  • Working right to left, write out the numbers 1, 2, 4, 8 and so on doubling each time to 128
• 28 has a 16 in it, leaving 12.
• 12 is 8 + 4 128 64 32 16 8 4 2 1 0 0 0 1 1 1 0 0

Memory & Storage: Lesson 4 Task 1: Binary Conversions

• Complete Task 1 the worksheet Navigation: → Student G-Suite → Computer Studies → GCSE Computer Science → Year 10 & 11 → Paper 1 → 1.2: Memory & Storage → Lesson 4 → Task 1: Binary Conversions

Memory & Storage: Lesson 4 Plenary In pairs:

1. Which numbers are stored in one bit?
2. How many bits are there in a nibble and a byte?
3. What are the units after a kilobyte?
4. What is zero in binary?
5. What is 255 in binary?
6. What is 39 in binary?