Structure And Function Of The Processor

Question 1

What does the Arithmetic Unit do?

Answer 1

Performs arithmetic operations on the data.

Question 2

What does the Logic Unit do?

Answer 2

Performs logical operations on the data.

Question 3

What is the ALU ( arithmetic logic unit)

Answer 3

The problem solving part of the processor.

Question 4

What does the Control Unit (CU) do?

Answer 4

It coordinates and controls the activities of the CPU, (directing the flow of data between the CPU and other devices.)

Question 5

What is a Register?

Answer 5

Special memory cells that operate at very high speed on the CPU

Question 6

What is usually stored in the Registers?

Answer 6

All arithmetic, logical or shift operations stored in registers

Question 7

What does the Program Counter(PC) do?

Answer 7

Stores the location of the NEXT instruction to execute

Question 8

What does the Accumulator do?

Answer 8

It stores the intermediary result of processing.

Question 9

What does the Memory address register (MAR) do ?

Answer 9

It hold the address of the memory location from which data is to be FETCHED or to which data is to be written.

Question 10

What does the memory data register(MDR) do?

Answer 10

Temporarily stores the data read from or written to memory.

Question 11

What does the Current Instruction Register (CIR) do?

Answer 11

Hold the current instruction being executed

Question 12

What is the Fetch-Decode-Execute Cycle?

Answer 12

The sequence of operations involved in executing an instruction can be divided into three phases—- fetching, decoding and executing it. The cycle repeats until the instruction is executed.

Question 13

How the registers are used in Fetch-decide-execute cycle?

Answer 13

1. Address of next instruction copied from PC to the MAR
2. The instruction held at the address is copied to the MDR, at the same time the content of pc is deleted so that it holds the address of the next instruction
3. Content of MDR copied to the CIR
4. Instruction in CIR gets decoded. Then split into opcode and operand
5. The instruction is carried out on the operand

Question 14

What is clock speed ?

Answer 14

The system clock, generating a series of signals, switches between 0 and 1 several million times per second and synchronising CPU operations .

Question 15

Why is the clock speed a factor of CPU performance?

Answer 15

The CPU cannot perform operations faster than the clock cycle. The greater the clock speed the faster instructions will be executed

Question 16

What is cache?

Answer 16

A small amount of expensive, very fast memory inside the CPU.

Question 17

Why is cache a factor of CPU performance?

Answer 17

When an instruction is fetched from main memory it is copied into the cache so if it’s needed again, it can be fetched from cache, quicker than from main memory, so it increases its speed.

Question 18

Number of cores ?

Answer 18

Instructions are fetched and executed one at a time in a serial manner.

Question 19

How does the number of cores change the COU performance?

Answer 19

Each core is able to process a different instruction at the same time with its own fetch-execute cycle, making the processor two or 4 times faster. ( depending on the amount of cores)

Question 20

What is pipelining?

Answer 20

A way to increase the performance of the CPU, by making the next instruction to be fetched while the one before being executed.

Question 21

What does the address bus do ?

Answer 21

Transmits the memory addresses of words that are used as operand sin program instructions

Question 22

What does the data bus do?

Answer 22

A two way directional path for moving data and instructions between system components

Question 23

What does the control bus do ?

Answer 23

Transmits commands, timings and specific status information between system components( both directions)

Question 24

What is the Von Neumann architecture?

Answer 24

Instructions and data are stored in a common main memory and transferred using a single shared bus.

Question 25

Harvard architecture?

One advantage to it ?

Answer 25

Separates the data and instructions into separate memories using different buses.

Programs no longer competing for the same bus.

Question 26

3 Advantages of Von Neumann architecture.

Answer 26

• almost all general purpose computers are based on its principles
• simplifies the design of the CU
• data from memory and from device are accessed in the same way