1 Hardware Flashcards
Role of the Control Unit
Supervises the fetch decode execute cycle
Sends and receives Signals from all parts of the computer
Decodes instructions
Role of ALU
Processes and manipulates data
Carries out simple arithmetic or logic operations
General role of the registers
Store details and results of instructions
Properties of registers
Temporary fast action storage
Role of CIR
Current instruction register
Stores instructions currently being executed
Role of PC
Program counter
Stores memory location of next instruction to be carried out
Role of MAR
Memory address register
Stores memory location where data is being written to or read from
Role of ACC/Accumulator
Stores calculation results
Role of address bus
Carries memory address of next instruction/bit of data to be retrieved
Role of data bus
Transfers instructions and data
Control bus
Used to communicate with other parts of computer - carries control info
Cache memory definition
Fast access temporary storage on the CPU
How increasing cache memory affects performance
More cache memory - faster performance time
Advantages of cache memory
Disadvantage of cache memory
✅ can be accessed quickly so programs run faster
❌ expensive
Clock speed definition
Speed at which processor operates - instructions executed per second
How clock speed affects performance
Faster clock speed
More fetch decode execute cycles per second - more instructions executed per second
Instructions are processed faster
RISC definition
Reduced instruction set computer
Can process a large number of simple instructions
RISC ✅
✅ can process simpler instructions quickly
Less power consumption, less heat generated, less circuitry needed
CISC definition
Complex instruction set computer
Processes a large number of complex instructions
CISC ✅ and ❌
✅ complex instructions can be processed quickly without having to be broken down into smaller ones
❌ larger circuitry, more energy and heat generated
RAM summary
Temporary, can be changed, volatile
ROM summary
Permanent, can’t be changed, non-volatile
Volatile definition
Data is lost when power is switched off
Flash memory summary
Permanent, can be changed, non-volatile
