RAM & ROM (AQA GCSE Computer Science)

Revision Note

Robert Hampton

Expertise

Computer Science Content Creator

RAM

What is RAM?

  • RAM (Random Access Memory) is primary storage that is directly connected to the CPU and holds the data and instructions that are currently in use
  • RAM is volatile which means the contents of RAM are lost when the power is turned off
  • For the CPU to access the data and instructions they must be copied from secondary storage
  • RAM is very fast working memory, much faster than secondary storage
  • RAM is read/write which means data can be read from and written to
  • In comparison to ROM, it has a much larger capacity

ROM

What is ROM?

  • ROM (Read Only Memory) is primary storage that holds the first instructions a computer needs to start up (Bootstrap)
  • ROM contains the BIOS (Basic Input Output System)
  • ROM is a small memory chip located on the computers motherboard
  • ROM is fast memory, much faster than secondary storage but slower than RAM
  • ROM is non-volatile which means the contents of ROM are not lost when the power is turned off
  • ROM is read only which means data can only be read from
  • In comparison to RAM, it has a much smaller capacity

Differences between RAM & ROM

Feature RAM ROM
Speed Very fast Fast (slower than RAM)
Capacity Gigabytes (GB) Megabytes (MB)
Stores Programs and data in use Bootstrap (start-up instructions)
Read/Write Read & write Read only
Volatile/Non-volatile Volatile Non-volatile

Worked example

State two reasons why computers have more RAM than cache memory [2]

Answer

  • RAM is cheaper (per byte than Cache)
  • The capacity of cache will usually be big enough to store currently open programs and data

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Robert Hampton

Author: Robert Hampton

Rob has over 16 years' experience teaching Computer Science and ICT at KS3 & GCSE levels. Rob has demonstrated strong leadership as Head of Department since 2012 and previously supported teacher development as a Specialist Leader of Education, empowering departments to excel in Computer Science. Beyond his tech expertise, Robert embraces the virtual world as an avid gamer, conquering digital battlefields when he's not coding.