Craig 'n' Dave

OCR GCSE (J277) SLR 1.2 – Memory and Storage

This download provides you with a zip file which contains all the resources you will need to deliver this topic.

It includes:

  • Student Learning Record Workbook (for use by students)
  • Student Learning Record Answers (for use by teachers)
  • End of Topic test and answers
  • Lesson PowerPoint’s for every lesson
  • Any associated answers or references sheets for class activities

This topic covers:

1.2.1 Primary storage (Memory)

  • The need for primary storage
  • The difference between RAM and ROM
  • The purpose of ROM in a computer system
  • The purpose of RAM in a computer system
  • Virtual memory

1.2.2 Secondary storage

  • The need for secondary storage
  • Common types of storage
  • Optical
  • Magnetic
  • Solid state
  • Suitable storage devices and storage media for a given application
  • The advantages and disadvantages of different storage devices and storage media relating to these characteristics:
  • Capacity
  • Speed
  • Portability
  • Durability
  • Reliability
  • Cost

1.2.3 Units

  • The units of data storage:
  • Bit
  • Nibble (4 bits)
  • Byte (8 bits)
  • Kilobyte (1,000 bytes or 1 KB)
  • Megabyte (1,000 KB)
  • Gigabyte (1,000 MB)
  • Terabyte (1,000 GB)
  • Petabyte (1,000 TB)
  • How data needs to be converted into a binary format to be
    processed by a computer
  • Data capacity and calculation of data capacity requirements

1.2.4 Data storage


  • How to convert positive denary whole numbers to binary numbers (up to and including 8 bits) and vice versa
  • How to add two binary integers together (up to and including 8 bits) and explain overflow errors which may occur
  • How to convert positive denary whole numbers into 2-digit hexadecimal numbers and vice versa
  • How to convert binary integers to their hexadecimal equivalents and vice versa
  • Binary shifts


  • The use of binary codes to represent characters
  • The term ‘character set’
  • The relationship between the number of bits per character in a character set, and the number of characters which can be represented, e.g.:
  • Unicode


  • How an image is represented as a series of pixels, represented in binary
  • Metadata
  • The effect of colour depth and resolution on:
  • The quality of the image
  • The size of an image file


  • How sound can be sampled and stored in digital form
  • The effect of sample rate, duration and bit depth on:
  • The playback quality
  • The size of a sound file

1.2.5 Compression

  • The need for compression
  • Types of compression:
  • Lossy
  • Lossless

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