Computer Systems 1.1

Question 1

`What is a processor and what does it do + 2 main types

Answer 1

A processor is a special component that processes data and instructions to other components within the computer.
2 main types are:
Central Processing Unit
Graphical Processing Unit

Question 2

What is primary storage and what are the two main types

Answer 2

memory in which the computer can store the data or instructions that are currently in use.
The two main types are:
Random Access Memory(RAM)
Read-only Memory(ROM)

Question 3

What is secondary storage and name 4 types

Answer 3

memory in which computer can store data or instructions which are not currently in use
main types are:
Hard Disk Drive(HDD)
Solid State Drive(SSD)
Compact Disk(CD)
Flash(USB Drive)

Question 4

What does input and output devices allow users to do and give 4 examples

Answer 4

allows users to input data into the computer, or receive data output from the computer.
Examples:
Keyboard
Mouse
Monitor
Speakers

Question 5

What is an embedded system and give 3 examples

Answer 5

computer system built into another device to support its operation
Washing machines
Digital cameras
Sat-Navvs

Question 6

What does the ALU do (3 marks)

Answer 6

Performs all arithmetic and logic operations of the CPU, such as:
Addition and subtraction, multiplication and division
Comparisons such as whether numbers are equal or if one is greater than another
Logic Operations (AND OR NOT)

Question 7

What does the Control Unit do and give the two main components of the Control Unit

Answer 7

Transmits control signals to other components of the CPU
follows the f-d-e cycle to execute program instructions
2 main components of the CU is:
The clock, which coordinates the CPU’s activity
The decoder, which decodes program instructions

Question 8

What are Registers and give two features

Answer 8

tiny amounts of quick memory within the CPU
Used to hold information needed for the CPU to work
Each register holds a specific piece of information

Question 9

Name 4 registers

Answer 9

Program Counter
Memory Data Register
Accumulator
Memory Address Register

Question 10

What is the function of the MAR

Answer 10

MAR holds address of the location in memory where data is to be retrieved or stored

Question 11

What is the function of the accumulator

Answer 11

Accumulator holds the result of calculations and operations performed by the ALU

Question 12

What is the function of the MDR

Answer 12

MDR holds data that has been retrieved from memory or that is about to be stored in memory

Question 13

What is the function of the Program Counter

Answer 13

PC holds the memory location address of the next instruction to be performed by the CPU

Question 14

What are Registers that have predetermined purpose in the cpu known as

Answer 14

Special purpose Registers

Question 15

What happens at the fetch stage ( 3 marks)

Answer 15

CU copies memory address from the program counter to the MAR
Data in that memory address is then fetched from memory and stored in the MDR.
The PC increments to point to the address of the next instruction

Question 16

What happens at the decode stage? (2 marks)

Answer 16

CU decodes instruction in MDR, sends control signals to the component within or outside the CPU that needs to act

Question 17

What happens at the execute stage? ( 2 marks)

Answer 17

Operation indicated by the instruction is performed by the appropriate component. For example, completing a calculation or logic operation.

Question 18

What is the purpose of the CPU?

Answer 18

To process data and instructions to make a computer system function correctly

Question 19

Name the parts of a CPU

Answer 19

CU/PC MDR/MAR ALU/ACC

Question 20

Define core

Answer 20

A processing unit within a CPU which contains an ALU, CU and registers.

Question 21

Why doubling the cores does not necessarily double CPU speed

Answer 21

Some software thats being run on computer system might not support multicore processing. Other factors

Question 22

Why computer systems have more cache than ram?

Answer 22

cache expensive comparaed to ram, fetchin data from ram takes much longer than fetchiin from cacahe

Question 23

Explain four benefits of using an embedded system in a microwave instead of general purpose computer ( 4 marks)

Answer 23

Highly efficient at performing tasks.
Extremely reliable.
Easy to design.
Cheap to produce.

Question 24

Disadvantage of using too many cores ( 2 marks)

Answer 24

Processing may not be split between cores
Software may not support multi-core