Lesson 1: Computer systems and system software

Lesson 1: Computer systems and
system software

Computer systems

Computing

Osas Odiase Asemota

Identify computer systems

Explain the role of system software

Describe Operating systems

2

In this lesson you will:

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3

Identifying computer systems

What is a computer
system?

Computer systems are a

combination of;

●

Hardware

–

Internal

–

Peripheral

●

Software

That work together to make up a

computer

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What is a computer?

A programmable
device that takes in
data, processes it into
useful information,
and then outputs the
information so it can
be used.

What is a computer?

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Categorising computers

A mobile phone and a coffee

maker are both computers, but

they are very different devices.

We categorise computers as

either:

● General purpose

● Embedded

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General Purpose

Embedded

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Mobile phone?

General Purpose

Embedded

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Mobile phone?

General Purpose

Embedded

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Coffee maker?

General Purpose

Embedded

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Coffee maker?

General purpose
computers

Devices that have a variety of uses,

the user chooses the task for the

computer to complete.

Mobile phone

● Lots of apps

● Can make phone calls

● App selected by the user

More specialised, they can only do

a limited number of things, but

they do them very well.

Coffee maker

● No apps

● Very good at making coffee

● User cannot change the task it

completes.

Embedded systems

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Spot the embedded
systems

The computers around us are

either general purpose or

embedded systems.

Can you spot all the computers in

this room and categorise them as

either;

● General purpose

● Embedded systems

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Resume once you’re finished

Spot the embedded systems

Can you spot all the computers in
this room and categorise them as
either;
● General purpose
● Embedded systems

Pause the video to
complete your task

Spot the embedded
systems

General purpose

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Spot the embedded
systems

General purpose

● Mobile phone

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Spot the embedded
systems

General purpose

● Mobile phone

● Laptop

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Spot the embedded
systems

General purpose

● Mobile phone

● Laptop

● Tablet

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Spot the embedded
systems

General purpose

● Mobile phone

● Laptop

● Tablet

● Games console

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Spot the embedded
systems

Embedded systems

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Spot the embedded
systems

Embedded systems

● Coffee maker

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Spot the embedded
systems

Embedded systems

● Coffee maker

● Vacuum robot

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Spot the embedded
systems

Embedded systems

● Coffee maker

● Vacuum robot

● Thermostat

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Spot the embedded
systems

Embedded systems

● Coffee maker

● Vacuum robot

● Thermostat

● Security system

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Spot the embedded
systems

Embedded systems

● Coffee maker

● Vacuum robot

● Thermostat

● Security system

● Bluetooth speaker

● Printer

● Smoke alarm

● TV

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General purpose
computers

Key characteristics

● Used for many different types of

tasks

● Lots of resources — memory,

storage, CPU cores

● Most uses require a user

Key characteristics

● ???

● ???

● ???

Embedded systems

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General purpose
computers

Key characteristics

● Used for many different types of

tasks

● Lots of resources — memory,

storage, CPU cores

● Most uses require a user

Key characteristics

● Specialised to a small number of

tasks

● Limited resources - just enough

● Users are not always necessary

Embedded systems

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The startup sequence

The startup sequence

Computers are a combination of:

● Hardware components

● Software

You are going to examine how they

work by looking at what happens

when you press the power

button.

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Credit: Pixabay

The startup sequence

The CPU

The Central Processing Unit, is a

large chip inside the computer.

It is the brains of the computer: it

controls everything.

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Credit: Pixabay

The startup sequence

RAM

Random Access Memory

● RAM is both readable and

writable. You can add, change,

and delete data stored in RAM.

● It is volatile. Without power all

the data stored in RAM is lost.

● It is fast to read/write.

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Credit: Pixabay

The startup sequence

ROM

Read-Only Memory

● ROM is read-only

● ROM is non-volatile memory,

which means it does not need

power to keep the data inside it

● It is also fast

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Credit: MOS6502, Wikimedia Commons

The startup sequence

Hard drive

The hard drive (sometimes called

the hard disk) is the main storage

device in your computer.

If you have files and folders on your

computer, they are stored on the

hard drive. The Operating system is

also stored on the hard drive.

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Credit: Pixabay

The startup sequence

BIOS

Contains all the basic code for

controlling your computer

hardware.

When you startup your computer,

you may see a black screen

displaying ‘Press F2 for Setup’. This

is the BIOS.

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Credit: Pixabay

The startup sequence

Your challenge.

On your worksheet you have two

tasks to complete.

1. Match the components to the

definitions

2. Put the steps of the startup

sequence in the correct order.

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

Pause the video to
complete your task

Resume once you’re finished

The startup sequence

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

The startup sequence

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

CPU starts up and fetches the BIOS
from ROM

The startup sequence

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

Instructions from BIOS are loaded into
RAM

CPU starts up and fetches the BIOS
from ROM

The startup sequence

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

Instructions from BIOS are loaded into
RAM
BIOS starts up the monitor and
keyboard

CPU starts up and fetches the BIOS
from ROM

The startup sequence

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

Instructions from BIOS are loaded into
RAM
BIOS starts up the monitor and
keyboard

BIOS checks the computer is working

CPU starts up and fetches the BIOS
from ROM

The startup sequence

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

Operating system is fetched from
secondary storage

Instructions from BIOS are loaded into
RAM
BIOS starts up the monitor and
keyboard

BIOS checks the computer is working

CPU starts up and fetches the BIOS
from ROM

The startup sequence

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1

2

3

4

5

6

7

8

The boot sequence begins

The BIOS hands control over to the
Operating system

Operating system is fetched from
secondary storage

Instructions from BIOS are loaded into
RAM
BIOS starts up the monitor and
keyboard

Operating system is loaded into RAM

BIOS checks the computer is working

CPU starts up and fetches the BIOS
from ROM

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System software

System software

Most computer systems require more

than just a program to run.

Another layer of software is required

called system software.

There are two main types of system

software

● Operating systems

● Utility software

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Credit: Pixabay

System software

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Software

System software

Hardware

Text editors

Video players

Browsers

IDEs

Video games

Operating

systems

BIOS

Encryption

CPU

Memory

Storage

Peripherals

Interpreters

Operating systems

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Operating systems are pieces of

software that regulate interactions

between software and hardware.

There are lots of different Operating

systems. The most popular are:

● Windows

● macOS

● Linux

● Android

Credit: Pixabay

Pause the video to
complete your task

Resume once you’re finished

Operating systems

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Roles of the Operating system:

● Error handling

● Program management

● Memory management

● Interaction with the user

● Processor management

● Input and output

● Security

● File management

Credit: Pixabay

Program management

Security

Memory management

File handling

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The Operating system controls where each piece of
data is stored in RAM.

Program management

Security

Memory management

File handling

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The Operating system controls where each piece of
data is stored in RAM.

Input and Output

Processor management

File management

Interaction with the user

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Instructions are executed by the CPU, but the
Operating system controls which instructions are fed
in to be executed.

Input and Output

Processor management

File management

Interaction with the user

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Instructions are executed by the CPU, but the
Operating system controls which instructions are fed
in to be executed.

Error handling

Security

Interaction with a user

Input and Output

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The Operating system captures data from peripherals
and provides data to the output devices to display to
the user.

Error handling

Security

Interaction with a user

Input and Output

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The Operating system captures data from peripherals
and provides data to the output devices to display to
the user.

File management

Input and Output

Error handling

Interaction with the user

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When you save data to your hard drive, the Operating
system will find an available section of storage and
send the data to be written to that location.

File management

Input and Output

Error handling

Interaction with the user

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When you save data to your hard drive, the Operating
system will find an available section of storage and
send the data to be written to that location.

Processor management

File management

Memory management

Security

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The Operating system stops unauthorised individuals
from accessing data on secondary storage or the data
in memory.

Processor management

File management

Memory management

Security

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The Operating system stops unauthorised individuals
from accessing data on secondary storage or the data
in memory.

Interaction with the user

Error handling

Security

Memory management

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When a program fails or encounters a problem, the
Operating system protects the wider system from
crashing.

Interaction with the user

Error handling

Security

Memory management

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When a program fails or encounters a problem, the
Operating system protects the wider system from
crashing.

Program management

Input and Output

Processor management

Security

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Often our computers are running multiple processes at
once. The Operating system makes sure that each
application has enough resources to accomplish its
tasks.

Program management

Input and Output

Processor management

Security

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Often our computers are running multiple processes
at once. The Operating system makes sure that each
application has enough resources to accomplish its
tasks.

Error handling

Interaction with the user

File management

Processor management

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The Operating system provides a graphical user
interface which makes operating the computer much
simpler.

Error handling

Interaction with the user

File management

Processor management

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The Operating system provides a graphical user
interface which makes operating the computer much
simpler.