CPU arch

Question 1

Computer hardware consists of……

Answer 1

Central Processing Unit (CPU)
Sound Card
Motherboard
Graphics Processing Unit (GPU)
Input & Output devices
Storage units (primary & secondary)

Question 2

Computer arch designs

Answer 2

Von Neumann model
Harvard model

Question 3

What does Harvard arch have separate memory for?
How is it different from Von Neumann arch?(2)

Answer 3

Harvard architecture has separate memory space for data and instruction.

Harvard differs from Von Neumann architecture which employs a single bus to both fetch instructions from memory and transfer data from one part of a computer to another.

Both the concepts are similar except the way they access memory locations

Question 4

Idea behind Harvard arch?

Answer 4

The idea behind the Harvard architecture is to split the memory into two parts:

one for data
one for programs

Question 5

What is it based on and what does it do?

Answer 5

Based on the original Harvard Mark I (1944) relay based computer which employed a system that would allow both data and transfers and instruction fetches to be performed at the same time.

Question 6

Harvard model

Answer 6

…………………………………ALU
Instruction mem<—ControlUnit—>Data mem
………………………………… I/O

Question 7

Vonneumann model-Who created it?Why?
What did he work on?
What are the components?

Answer 7

-Renowned mathematician and physicist John Von Neumann in 1945.
-Able to store instructions in the memory along with the data on which the instructions operate
-Harvard Mark I at IBM
-central processing unit (CPU),memory unit, input/output (I/O) interfaces

Question 8

3 main components CPU

Answer 8

CPU heart of computer system 3 main components:
the Arithmetic and Logic Unit (ALU)
the control unit (CU)
Registers
-Accumulator (ACC)
-Program Counter (PC)
-Instruction Register (IR)
-Memory Address Register (MAR)
-Memory Data Register (MDR)

Question 9

What do they do?
ALU
CU
Registers
Mem unit
I/O interface

Answer 9

*The ALU is responsible - carrying out all arithmetic and logic operations on data.
*The control unit (CU) determines - order of flow of instructions - need executed -> programs -> issuing control signals -> hardware.
*The registers -> temporary storage locations store addresses of the instructions - need executed.
*The memory unit = RAM, which- main memory used to store program data + instructions.
*The I/O interface allows users - communicate with outside world : storage devices.

Question 10

Buses-What do they do?What are they?
What does the system bus control?

Answer 10

Buses transfer the data + instruction locations:
The System bus:
Address bus
Data bus
Control bus
The system bus controls the flow of data through the network

Question 11

VNM vs Harvard

Answer 11

VNM- Theoretical design based->stored program computer concept.
Same memory for data and instructions
Processor-2 clock cycles-execute instruction.
Simpler CU design
Data transfer+instruction fetches X perform same time
Used in personal computers+workstations+laptops
Havard - Modern design - Havard Mark 1
Seperate memory address- data+instructions.
Processor-1clock cycle-execute instruction
More complicated design -2 separate buses
Data transfer+instructions fetches peform same time
Used - microprocessors

Question 12

CPU

Answer 12

Computing equivalent of the human brain
main component -> computer, processing all the data and instructions

Question 13

CPU components

Answer 13

CU
ALU
Internal mem
Registers
Buses

Question 14

CU

Answer 14

Supervises FDE cycle
Sends + receives signals from all parts of the computer
Ensures processes are completed in the correct order

Question 15

ALU

Answer 15

Processes + manipulates data
Performs simple calculations
Carries out logical operations

Question 16

Internal mem

Answer 16

Known - cache memory (level 1)
Fast access temporary storage on the CPU
Data is moved from the cache to internal memory when not being used

Question 17

Registers

Answer 17

Current Instruction Register (CIR)
-Stores the instruction that is currently being used by the CPU
Program Counter (PC)
-Stores the memory location of the next required instruction
Accumulator (ACC)
-Stores the results of the calculations made by the ALU
Memory Address Register (MAR)
-Stores the memory address location where data is currently being read/written
Memory Data Register (MDR)
-Stores the data currently being read/written

Question 18

Buses

Answer 18

->printed circuits -> motherboard - connect components: I/O devices to the CPU + other parts of a computer:
Address Bus–Sends info about where data needs to go -> sending an address to the memory. Only sends data in 1 direction
Data Bus–Sends data to/from memory. Data flow either direction along - data bus
Control Bus–Carries commands from CPU and returns status signals from the device currently in use

Question 19

FDE cycle

Answer 19

-The processor checks program counter-which instruction to run next.
-The program counter gives address value-> memory of where next instruction is.
-The processor fetches instruction value-> memory location
-Once instruction fetched needs- decoded+executed.
-The control unit checks instruction-> instruction register. Instruction - decoded to determine action - needs -carried out
-The action being executed -depended-> action being carried out
-Once- complete, processor goes back-program counter find next instruction.
-Cycle rep until program completed.