Computers

Question 1

what is the general purpose computer designed to do

Answer 1

able to carry out many different tasks

Question 2

example of a general purpose computer

Answer 2

1) Tablets
2) smartphones
3) game consoles
4) media systems in cars

Question 3

Define Hardware

Answer 3

the physical components of the computer, such as the central processing unit (CPU), hard disk, monitor, keyboard and mouse.

Question 4

Define software

Answer 4

the programs that run on a computer.

Question 5

what is a CPU

Answer 5

A central processing unit.
- the most important processor in a given computer.
- the component of a computer system that controls the interpretation and execution of instructions

Question 6

Purpose of a CPU

Answer 6

• to process data and instructions
• to control the rest of the computer system

Question 7

components of a CPU (6)

Answer 7

1) control unit (CU)
2) Arithmetic Logic unit (ALU)
3) registers
4) cache
5) buses
6) clock

Question 8

Control Unit?

Answer 8

1) fetches, decodes and manages the execution of the instructions
2) issues control signals that control hardware
3) moves data around the system

Question 9

ALU?

Answer 9

• Arithmetic Logic unit
  1) Preforms logical decisions
  2) where calculations are done. (arithmetic)

Question 10

Register?

Answer 10

Small amount of high speed memory contained within the CPU. They are used by the processor to store small amounts of data that are needed during processing.

Question 11

Name 4 main registers

Answer 11

1) program counter (PC)
2) memory address register (MAR)
3) memory data register (MDR)
4) accumulator (ACC)

Question 12

Cache?

Answer 12

a small amount of high speed memory built directly within the processor. It is used to temporarily hold data and instructions that the processor is likely to reuse.
-> allows for faster processing

Question 13

Clock?

Answer 13

clock is in the CPU, used to coordinate all of the computer’s components.
- sends out a regular electrical pulse which synchronises all the components.

Question 14

Buses?

Answer 14

A bus is a high speed internal connection. Buses are used to send control signals and data between the processor and other components.

Question 15

define clock speed

Answer 15

The frequency of the pulses
- measured in hertz
- The higher the clock speed, the greater the number of instructions that can be performed in any given moment of time.

Question 16

Address bus?

Answer 16

carries memory addresses from the processor to other components such as RAM and input/output devices.

Question 17

Data bus?

Answer 17

carries the actual data between the processor and other components.

Question 18

Control bus?

Answer 18

carries control signals from the processor to other components.

Question 19

Von Neumann Architecture

Answer 19

Von Neumann architecture is the design upon which many general purpose computers are based. This architecture uses the stored program concept. The key elements of Von Neumann architecture are:
- data and instructions are both stored as binary digits
- data and instructions are both stored together in the same RAM
instructions are fetched from memory one at a time and in order - serially
- the processor decodes and executes an instruction, before cycling around to fetch the next instruction
- the cycle continues until no more instructions are available

Question 20

The fetch-decode-execute cycle

Answer 20

The fetch-decode-execute cycle is followed by a processor to process an instruction. The cycle consists of several steps:

1) The memory address held in the program counter is copied into the MAR.
2) The address in the program counter is then incremented - or increased - by one. The program counter now holds the address of the next instruction to be fetched.
3) The processor sends a signal containing the address of the instruction to be fetched along the address bus to the computer’s memory.
4) The instruction held in that memory address is sent along the data bus to the MDR.
5) The instruction held in the MDR is copied into the CIR.
6) The instruction held in the CIR is decoded and then executed. The results of processing are stored in the ACC.
7) The cycle then returns to step one.

Question 21

Factors affecting the CPU performance

Answer 21

1) clock speed
2) clock size
3) number of cores

Question 22

cache size

Answer 22

Cache is a small amount of high-speed random access memory (RAM) within the processor. It is used to temporarily hold data and instructions that the processor is likely to reuse. This allows for faster processing as the processor does not have to wait for the data and instructions to be fetched from RAM.

The bigger its cache, the less time a processor has to wait for instructions to be fetched.

Question 23

number of cores

Answer 23

A processing unit within a CPU is known as a core. Each core is capable of fetching, decoding and executing its own instructions.

The more cores a CPU has, the greater the number of instructions it can process in a given space of time.

Question 24

embedded system

Answer 24

a small computer that forms part of a larger system, device or machine.

Question 25

example of an embedded system

Answer 25

• central heating systems
• engine management systems in vehicles
• domestic appliances, such as dishwashers and TVs
• digital watches
• electronic calculators
• GPS systems
• fitness trackers
• washing machine <3

Question 26

advantage of embedded systems

Answer 26

1) Their limited number of functions means they are cheaper to design and build.
2) They tend to require less power. Some devices run from batteries.
3) They do not need much processing power. They can be built using cheaper, less powerful processors.

Question 27

operating system

Answer 27

a collection or suite of programs that manages and controls the computer. e.g. Microsoft Windows