GCSE Computer Science (OCR) UPDATED
ACTUAL QUESTIONS AND CORRECT
ANSWERS
Arithmetic Logic Unit (ALU) - Correct answers✔✔Performs operations on data e.g. Addition,
subtraction
Control Unit (CU) - Correct answers✔✔Coordinating activities of the CPU
Registers - Correct answers✔✔Quick, small stores of data within the CPU
Memory Address Register (MAR) - Correct answers✔✔Holds memory address for data or a
instruction about to be used by the CPU
Memory Data Register (MDR) - Correct answers✔✔Holds actual data or instruction
Accumulator - Correct answers✔✔Stores results of calculations in the ALU
Program Counter (PC) - Correct answers✔✔Holds memory address of the instruction for each
cycle
Fetch - Correct answers✔✔The next instruction is retrieved by CPU from main memory
Decode - Correct answers✔✔The instruction is broken down and decided so computer can
understand
,Execute - Correct answers✔✔The CPU performs what the instructions told
Embedded System - Correct answers✔✔A computer system built within a large device e.g.
Camera, washer, car
Volatile - Correct answers✔✔Memory loses its data when power of
Non-volatile - Correct answers✔✔Memory retains its data when power is lost
Random Access Memory (RAM) - Correct answers✔✔Read/write - function is to load open
programs and operating system data currently in use - volatile
Read Only Memory (ROM) - Correct answers✔✔Can only be read, can't be changed, stores
essential programs to be run in order to boot the computer - non-volatile
Cache - Correct answers✔✔A type memory that stores copies of frequently used data, much
faster than RAM, lower capacity - closer to CPU
Buses - Correct answers✔✔Collection of wires that carry signals between various components of
the computer system
Central Processing Unit (CPU) - Correct answers✔✔Processes all of the data and instructions
that make the system work - can be effected by clock speed, number of cores, cache size
Clock speed - Correct answers✔✔How fast the computer does the FDE cycle
, virtual memory - Correct answers✔✔A memory management procedure needed when the RAM
is full so a temporary section is made which acts like a part of RAM
Flash memory - Correct answers✔✔Solid state storage, non-volatile, more reliable/durable but
can only be overwritten a limited number of times
Graphics Processing Unit (GPU) - Correct answers✔✔Handles graphics and image processing
Optical storage - Correct answers✔✔CD, DVD, Blue-ray
ADV: cheap,easy to transport
DIS: slow, less storage than hard drives, stored data degrades over time, cannot be written over
Magnetic storage - Correct answers✔✔Hard drives
ADV: fast access, stores large amounts of data, low cost
DIS: not very portable, easily be broken
Solid State storage - Correct answers✔✔USB, flash memory, SD
ADV: fast, small, light, easily potable, quiet
DIS: more expensive, storage capacity less, limited number erase/write cycles
Cloud stotage - Correct answers✔✔Data is stored on multiple servers in a remote location
ADV: secure, can be accessed anywhere, no need to buy
DIS: needs internet, download and upload can be effected by internet connection, less control if
data is held
ACTUAL QUESTIONS AND CORRECT
ANSWERS
Arithmetic Logic Unit (ALU) - Correct answers✔✔Performs operations on data e.g. Addition,
subtraction
Control Unit (CU) - Correct answers✔✔Coordinating activities of the CPU
Registers - Correct answers✔✔Quick, small stores of data within the CPU
Memory Address Register (MAR) - Correct answers✔✔Holds memory address for data or a
instruction about to be used by the CPU
Memory Data Register (MDR) - Correct answers✔✔Holds actual data or instruction
Accumulator - Correct answers✔✔Stores results of calculations in the ALU
Program Counter (PC) - Correct answers✔✔Holds memory address of the instruction for each
cycle
Fetch - Correct answers✔✔The next instruction is retrieved by CPU from main memory
Decode - Correct answers✔✔The instruction is broken down and decided so computer can
understand
,Execute - Correct answers✔✔The CPU performs what the instructions told
Embedded System - Correct answers✔✔A computer system built within a large device e.g.
Camera, washer, car
Volatile - Correct answers✔✔Memory loses its data when power of
Non-volatile - Correct answers✔✔Memory retains its data when power is lost
Random Access Memory (RAM) - Correct answers✔✔Read/write - function is to load open
programs and operating system data currently in use - volatile
Read Only Memory (ROM) - Correct answers✔✔Can only be read, can't be changed, stores
essential programs to be run in order to boot the computer - non-volatile
Cache - Correct answers✔✔A type memory that stores copies of frequently used data, much
faster than RAM, lower capacity - closer to CPU
Buses - Correct answers✔✔Collection of wires that carry signals between various components of
the computer system
Central Processing Unit (CPU) - Correct answers✔✔Processes all of the data and instructions
that make the system work - can be effected by clock speed, number of cores, cache size
Clock speed - Correct answers✔✔How fast the computer does the FDE cycle
, virtual memory - Correct answers✔✔A memory management procedure needed when the RAM
is full so a temporary section is made which acts like a part of RAM
Flash memory - Correct answers✔✔Solid state storage, non-volatile, more reliable/durable but
can only be overwritten a limited number of times
Graphics Processing Unit (GPU) - Correct answers✔✔Handles graphics and image processing
Optical storage - Correct answers✔✔CD, DVD, Blue-ray
ADV: cheap,easy to transport
DIS: slow, less storage than hard drives, stored data degrades over time, cannot be written over
Magnetic storage - Correct answers✔✔Hard drives
ADV: fast access, stores large amounts of data, low cost
DIS: not very portable, easily be broken
Solid State storage - Correct answers✔✔USB, flash memory, SD
ADV: fast, small, light, easily potable, quiet
DIS: more expensive, storage capacity less, limited number erase/write cycles
Cloud stotage - Correct answers✔✔Data is stored on multiple servers in a remote location
ADV: secure, can be accessed anywhere, no need to buy
DIS: needs internet, download and upload can be effected by internet connection, less control if
data is held
