1.1 Systems architecture Flashcards
What is the Central Processing Unit (CPU)
The CPU is where processes such as calculating, sorting and searching take place
What is the Fetch Decode Execute cycle (FDE)
Fetch:
The PC is checked as it holds the address of the next instruction to be executed
This address is used by the MAR to fetch instructions from RAM and bring it to the MDR
The address in the PC is incremented to point at the next instruction
Decode:
The instruction in the CU decodes it to see what needs to be done
Execute:
Does what the instruction is, e.g. go to RAM and fetch data to add it to the ACC
What is the Arithmetic Logic Unit (ALU)
Performs mathematical and logical calculations
What is the Control Unit (CU)
Synchronises data flow around the CPU
What is the cache
Stores frequently used instructions and it is faster for the CPU to access it compared to RAM
What are the registers
Memory Address Register (MAR) - temporarily stores the memory addresses used when searching for data in RAM
Memory Data Register (MDR) - temporarily hold the data that are read from or written from memory
Program Counter (PC) - hold the address of the next instruction to be executed by the processor
Accumulator (ACC) - stores the result of the calculation done by the ALU
See Von Neumann Architecture diagram flashcard
See Von Neumann Architecture diagram flashcard
What are the three factors affecting the performance of the CPU
Clock speed
Number of Cores
Cache size
Why does clock speed affect the performance of the CPU
The higher the clock speed is, the more FDE cycles the CPU can do. This is measured in Hertz (Hz)
Why does The number of cores affect the performance of the CPU
The more cores there are, the more FDE cycles can be executed simultaneously
Why does cache size affect the performance of the CPU
The more space there is in cache, the less frequently the CPU need to access RAM
What is an embedded system and the characteristics of it
A computer that has a dedicated function within a larger mechanical system
Low cost per unit
Low power consumption
Small size
What are examples of embedded systems
Washing machine
Traffic lights
Bluetooth speaker
