Transcript 1.7 Control, Models and Virtual Machines

GCSE COMPUTER SCIENCE
Computers
1.7 Control, Models and Virtual Machines
Control Systems
Examples of Control Systems include:
Examples of control systems
include:
- Air conditioning and central
heating systems
- Security systems and burglar
alarms
- Automatic doors
- Manufacturing processes
- Traffic lights and pedestrian
crossings
Sensors
ACTIVITY
Microcontroller
Output Devices
Draw this control system diagram in your book.
This diagram show the different parts of a typical control system.
Microcontrollers
Microcontrollers are small computers usually with a processor, memory and programmable input and output
peripherals.
ACTIVITY
Write this definition of a
microcontroller in your book.
Arduino
Microcontrollers are often embedded to provide automated control systems such as car engine control systems,
robots and games consoles.
Sensors
Sensors are input devices that are used to measure physical properties such as temperature, light, pressure, sound
and humidity. They send signals to the microprocessor.
ACTIVITY
Write this definition of a sensor in
your book.
Data such as pressure, light and temperature is analogue. Computers can only work with digital data.
Actuators
An actuator is a type of motor that is used as an output device for a control system. They allow the system to control
movement or action.
ACTIVITY
Write this definition of an actuator
in your book.
An example is the Thames flood barrier, actuators are used to open and close the barrier gates.
Activity 1
Identify the control key terms from the descriptions:
Model Type
Description
Microcontroller
Small computers usually with a processor, memory and programmable
input and output peripherals.
Sensor
Input devices that are used to measure physical properties such as
temperature, light, pressure, sound and humidity. They send signals to
the microprocessor.
Actuator
Type of motor that is used as an output device for a control system. They
allow the system to control movement or action.
Computational Models
There are three different computational models used in computer science. You need to be able describe the
characteristics of each of these models:
Sequential
Parallel
Multi-Agent
Sequential
A sequential computational model is one in which instructions are executed one after another.
There may be branches in the program, but the general principle is that each instruction follows on from the previous
one.
ACTIVITY
Write the definition of a sequential model in your book.
Parallel
A parallel computational model is one in which each program instruction is executed simultaneously on multiple
processors in order to get the results faster. Using multi-cores in processors is an example of parallel computing. It is by
using parallel processing that super computers are getting faster and faster.
ACTIVITY
Write the definition of a parallel model in
your book.
Multi-Agent
A multi-agent computational model is one in which computer systems co-operate and co-ordinate with other agents to
achieve their goals.
ACTIVITY
Write the definition of a multi-agent
model in your book.
Swarm robots are examples of multi-agents.
Activity 2
Identify the model type from the description: sequential, parallel, multi-agent.
Model Type
Description
Sequential
One in which instructions are executed one after another. There may be
branches in the program, but the general principle is that each
instruction follows on from the previous one.
Multi-agent
One in which computer systems co-operate and co-ordinate with other
agents to achieve their goals. Swarm robots are examples of multiagents.
Parallel
One in which each program instruction is executed simultaneously on
multiple processors in order to get the results faster.
Virtual Machines
A virtual machine is a layer of software that allows one computer to simulate another and to run more than one
operating system.
Activity 3
Use the Internet to help you find the answer to the following question:
Question
Information
Find out more information about
Parallels.
Find out more information about
VM Ware.
HINT
Use their websites. Find out information such as cost, operating systems, features, uses
etc.
How Do They Work?
The virtual machine acts as if it is a hardware machine, ‘deceiving’ the guest operating system into believing that it is
installed on a computer when in fact it is not.
With the continued increase in processor power, reduction in memory cost and increase in storage capacity, most
desktop computers are capable of running many operating systems simultaneously.
Guest Operating System
Virtual Machine
Host Operating System
Hardware
Activity 4
Answer these questions in your own words:
Question
What is a virtual machine?
Explain how a virtual machine
works.
Answer
A virtual machine (VM) is an emulation of a computer system. Virtual
machines provide functionality of a physical computer. Their implementations
may involve specialised hardware, software, or a combination.
A virtual machine is usually software that is installed on a computer. It allows a
guest OS to be installed within this software. The guest OS then runs inside a
window on the host OS, allowing you to use the guest OS at the same time as the
host OS.
Activity 5
Use the Internet to help you find the answer to the following question:
Question
What program is used to install
Windows a on Mac computer?
What are the steps to installing
Windows on a Mac computer using
this program?
Hint: Look on the Apple website!
Answer
BootCamp
1.
2.
3.
4.
5.
6.
Check System Requirements
Get a Windows disk image or CD/DVD
Open Boot Camp Assistant
Format your Windows partition
Install Windows
Restart your computer
Modelling
Software is often used to model aspects of the real world. They can be used to make predictions about how real world
systems will respond to different events.
They allow us to try things out without putting people in danger or damaging equipment.
An example is a flight simulator that allows trainee pilots to practice in a controlled environment safely.
Activity 6
Answer these questions in your own words:
Question
Answer
Why is software used to simulate
and model aspects of the real
world?
Computer models are cheaper to setup than alternative methods that could be
used to predict what will happen in a system, eg building a prototype. Other
benefits include being able to: make alterations and quickly see the outcomes,
repeat tests several times over, learn from "what if?" scenarios and model
dangerous situations safely.
Give some examples of software
models or simulations.
Supermarket queues
Stresses which will be borne by a new bridge
Traffic flow in a new road system
Grades for a GCSE class
Activity 7
Crossword
Create a crossword based on this topic using the online crossword
generator linked below. It should have a minimum of 10 questions.
When you have finished, paste your crossword on to a Powerpoint slide
and name it 1.7 Control Crossword.
Print out one copy (include your name) and stick it in your book.
http://puzzlemaker.discoveryeducation.com/CrissCrossSetupForm.asp
puzzle maker criss-cross