RAM & ROM (Edexcel IGCSE ICT): Revision Note

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 (temporary)

• 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

• RAM capacity can be increased to improve performance

ROM

What is ROM?

• ROM (Read Only Memory) is primary storage that holds the first instructions a computer needs to start up (Boot file)

• 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

• ROM capacity can not be increased

• Some types of ROM can be changed

  • EPROM - erasable programmable read only memory

  • EEPROM - electronically erasable programmable read only memory

Differences between RAM & ROM

Flash memory

What is flash memory?

• Flash memory is a type of EEPROM (Electronically Erasable Programmable Read Only Memory)

• Non-volatile

• Fast access times

• Low power consumption

• Used in solid state drives, USB drives and SD memory cards