Memory & Storage is a core part of GCSE Computer Science. Revise the key concepts and common mistakes below, then lock them in with the free games.
RAMRandom Access Memory: volatile main memory holding running programs and data.
ROMRead Only Memory: non-volatile memory holding firmware such as the bootloader.
Virtual memoryUses part of secondary storage as if it were RAM when main memory is full.
HDDHard Disk Drive: magnetic spinning-platter storage with high capacity but slower access than SSD.
SSDSolid State Drive: flash-memory storage with no moving parts, faster than HDD.
Optical storageStorage on CD, DVD or Blu-ray, read by a laser; useful for long-term distribution.
Central processing unitThe chip that executes program instructions through the fetch-decode-execute cycle, containing the control unit, ALU and registers.
RegisterA very small, very fast storage location inside the CPU holding one value during processing, such as an address, instruction or result.
System busesThe sets of connections carrying information inside a computer: addresses on the address bus, data on the data bus, signals on the control bus.
Embedded systemA computer system with a dedicated function built into a larger device, such as the controller inside a washing machine or car engine.
Solid-state storageSecondary storage with no moving parts that stores data in flash memory chips, making it fast, quiet and resistant to shocks.
CPUCentral Processing Unit: executes instructions from memory using the fetch-decode-execute cycle.
ALUArithmetic Logic Unit: performs arithmetic and logical operations within the CPU.
Control unitCPU component that directs operations by interpreting instructions and sending control signals.
Questions where students often pick the tempting wrong answer — make sure you know the right one: