1.1 Characteristics of Contemporary Processors

Question 1

What is processor responsible for?

Answer 1

processor is responsible for processing data and executing the instructions of programs.

Question 2

What does ALU stand for and what is it responsible for?

Answer 2

It stands for Arithmetic logic unit and is responsible for :

• ->Calculations
• ->logical bitwise operations,
• ->comparisons between values
• ->shifting binary patterns

Question 3

What is decoding?

Answer 3

Instrcution gets splited to Opcode and operand which are analyzed to determine what needs to be done.

Question 4

What is Control unit responsible for?

Answer 4

• -> It uses control signals to enable data to be read from and written to the main memory
• -> It decodes every instruction
• -> It organizes the sequence of micro-operations
• -> It uses control signals to determine the operation the ALU

Question 5

What are the three buses?

Answer 5

• -> Address bus
• ->Data bus
• -> Control bus

Question 6

What is adress bus used for?

Answer 6

the address bus is used to specify the address of a memory location to either read data or write data to that memory location.

Question 7

What is data bus used for?

Answer 7

The data bus is used to transfer data and instructions to and from the processor and the other units of a computer system.

Question 8

What is control bus used for?

Answer 8

The control bus is used to send control signals that manage the operations inside the computer

Question 9

Give the 5(6) registers used in fetch-decode-execute cycle and their functions?

Answer 9

1. Program counter (PC): holds the current instruction
2. Current instruction register(CIR): holds the current instruction
3. Status register(SR): stores information about the result of the last instruction that the ALU executed. Finds errror or exception in process
4. Memory adress register(MAR): Temporarily holds the address of the memory location
5. Memory data register(MDR): Temporarily holds the data that are read or writtien from the main memory
6. accumulator: Stores the result of any calculation processed by the ALU.

Question 10

Explain the fetch-decode-execute cycle detailed

Answer 10

Fetch Stage
1.The program counter (PC) keeps the address of the next instruction to be executed.

2. The contents of the PC are copied to the memory address register (MAR).
3. Once the address of the instruction is placed on the address bus, the control unit instructs a memory read operation to allow the contents of the memory location to be transferred to the processor.
4. The instruction that is stored at the address is transferred by the data bus to the processor, and is saved in the memory data register (MDR).
5. The contents of the memory data register (MDR) are copied to the current instruction register (CIR).

Decode Stage
6.The control unit decodes the instruction to operand and opcode in CIR

Execution Stage
7.The instruction is executed.

Question 11

What are the factors affecting computer performance and how they do it?

Answer 11

1.Multiple Cores
The more cores a computer has, the more instructions it can execute at the same time.

2.Cache
Storing instructionsn that are oftenly used in cache reduces the amount of time it takes to access that instruction and pass it to a CPU core.

3. clock speed
   The greater the clock speed, the faster instructions are carried out and synchronized.
4. Instruction pipelining
   Pipelining is the process where each part of the processor works at the same time, fetching the next instruction while executing the last one. This causes the computer to avoid overwriting data and avoiding internal components being idle which means instructions are executed at a faster rate, which in turn improves processor performance.

Question 12

Types of proccesor?

Answer 12

1. CISC
2. RISC
3. Graphic processing unit (GPU)

Question 13

Differences between CISC and RISC

Answer 13

CISC

• ->Large number of complex, variable length instructions
• ->Instructions can take several clock cycles to be executed.
• ->Compound addressing modes
• ->Emphasizes hardware over software
• ->Makes efficient use of RAM

RISC

• ->small number of simple, fixed-length instructions
• ->One instruction is executed per clock cycle.
• ->Limited addressing modes
• ->Emphasizes software over hardware.
• ->Use a lot RAM, which can cause system bottlenecks

Question 14

What does GPU do and used for?

Answer 14

–>GPUs are designed for parallel processing

–>Used in graphics, video rendering, gaming and machine learning applications

Question 15

What are the two computer architectures and what are they?

Answer 15

1. Von neumann
   - -> both instructions and data are loaded into the same memory unit.
2. Harvard
   - -> Harvard architecture keeps instructions and data in separate memories.

Question 16

Give the differences between two computer architectures

Answer 16

Harvard architecture
–>Harvard architecture both memories can be accessed simultaneously. This minimizes the time for processor waiting while loading or saving data into memory.

–>Harvard architecture each memory can be adapted to meet the needs of a particular system. This makes it difficult to get hacked.

–>Harvard architecture is commonly used in embedded systems.

Von Neumann Architecture

–>Von Neumann architecture uses the same address and data buses for both instructions and data, sharing the same pathways which takes longer time compared to Harvard architecture.

–>von Neumann architecture allows for the instructions and data to be saved in the same memory. This makes it easy to get hacked

–> Von Neumann architecture is commonly used in general purpose computers.

Question 17

Give examples for input devices?

Answer 17

• ->Keyboard
• ->Webcam
• ->Magnetic stripe reader
• ->Barcode reader

Question 18

Give examples for output devices

Answer 18

• ->Speakers
• ->Printers
• ->Projector

Question 19

What does main memory contain?

Answer 19

• -> RAM
• -> ROM
• ->Cache
• ->Registers
• ->Virtual memory
• -> Flash memory

Question 20

What are the characteristics of RAM?

Answer 20

The characteristics of RAM are:

• ->short-term memory storage space
• ->It is volatile
• ->You can read and write to it
• ->It is quicker to access than secondary storage

Question 21

What are the characteristics of ROM

Answer 21

The characteristics of ROM are:

• ->It is non-volatile
• ->It is written by the computer manufacturer (so cannot be changed)
• ->Usually stores the BIOS
• ->Smaller capacity than RAM

Question 22

Differences between RAM and ROM

Answer 22

RAM

• ->Stores data and instructions during processing
• ->Volatile, data lost without power
• ->Read and write
• ->Usually several gigabytes

ROM

• ->Stores boot-up instructions set by the manufacturer
• ->Non-volatile, data remains after power switched off
• ->Read only
• ->A few megabytes in size

Question 23

What is virtual memory?

Answer 23

Virtual Memory is an area of disk used as an extension of memory, onto which currently running programs and data are copied when memory is full when another task has control of the processor, and then copied back into memory when needed

Question 24

What is flash memory?

Answer 24

Flash Memory is some microcontrollers use a memory chip to store instructions. Flash memory is non-volatile and can be both written to and read from.

Question 25

How does Magnetic storage work?

Answer 25

Devices which store information magnetically represent binary information using two magnetic states: polarised and unpolarised which equals to 0 and 1.

Question 26

How does optical storage work?

Answer 26

Optical devices are read from and written to
using lasers. Binary information is represented
by portions of the disc which either reflect or
scatter the incident laser light written in spiral
tracks on the disc’s surface.

Question 27

How does flash storage work

Answer 27

it uses electrical circuits to store infromation