1.1 - Systems architecture

Question 1

1.1.1 Architecture of the CPU

The purpose of the CPU

Answer 1

• process data and instructions by constantly repeating the FDE cycle

Question 2

1.1.1 Architecture

The fetch-decode-execute cycle

Answer 2

1. The program counter displays the address of the next instruction to be processed in the RAM. This value is copied into the MAR
2. The PC increments by 1, preparing the CPU for the next instruction to be fetched
3. The CPU checks the address in the RAM, to see if it matches the address held in the MAR
4. Instruction in RAM is transferred to the MDR
5. the instruction in MAR is copied into CIR
6. the instruction in the CIR is decoded and executed
7. any result of an exceution is stored in the ACC
8. cycle repeats

Question 3

1.1.1 Architecture of the CPU

common CPU components and their function

Answer 3

ALU: performs simple calculations and logical operations
CU: sends control signals to direct the operation of the CPU
Cache: to temporarily store data that is frequently accessed
Registors: temporary storage space for 1 instruction/address

Question 4

1.1.1 Architecture of the CPU

Von Neumann architecture:

Answer 4

MAR: holds the current address of the instruction, waiting to be fetched /stored
MDR: holds the instruction, waiting to be written to memory
Program Counter: holds the memory address of the next instruction, waiting to be processed
Accumulator: where calculation results from ALU are stored

Question 5

1.1.2 CPU performance

How does common characteristics of CPUs affect their performance?

Answer 5

Cache memory:
* more cache, higher performance = repeatedly used instructions can be stored so faster access

Clock speed:
* faster speed, faster a computer can perform the FDE cycle (more instructions processed each second)
* higher performance

Number of cores:
* more cored, higher performance = more instructions at once

Question 6

1.1.3 Embedded systems

Purpose, characteristics and examples of embedded systems

Answer 6

• computer system built into a larger machine to control the device
• performs specific tasks, stored in ROM
• has a limited number of functions: cheaper to build/design
• uses less power
• doesn’t need much processing power.

Eg: washing machine, microwave