The document outlines the definitions and classifications of software, including system and application software. It describes the role of the operating system in managing hardware and executing software, as well as various functions such as memory management, multitasking, and user account management. Additionally, it discusses interrupts and their role in handling multiple processes efficiently within a computer system.

1. Software
IGCSE CS

2. Competition
Come up with as many software as
possible in 3 minutes

3. Definition of a Software
A set of instructions written in a programming
language that performs one or more tasks to tell
the computer what to do.

4. "Inner look" on software - 2048

5. "Inner look" on software - basic shop
Code that will be run when the player decides to buy an item
- JUST ONE ACTION

6. Classification of Software
System Software Application Software

7. System Software
A variety of programs that a
computer needs to function.
Definition

8. System Software
A variety of programs that a
computer needs to function.
Definition
• Basic Input Output System (BIOS) - installed in
ROM. Enables all of the attached components to
initialise. Known as firmware.
Example

9. System Software
A variety of programs that a
computer needs to function.
Definition
• Basic Input Output System (BIOS) - installed in
ROM. Enables all of the attached components to
initialise. Known as firmware.
• Operating System - MAC, Windows, Android,
iOS.
Example

10. System Software
A variety of programs that a
computer needs to function.
Definition
• Basic Input Output System (BIOS) - installed in
ROM. Enables all of the attached components to
initialise. Known as firmware.
• Operating System - MAC, Windows, Android,
iOS.
• Device Driver (Part of the OS or Installed
manually) - A software that enables hardwares
to communicate with the operating system
(Plug and play).
Example

11. System Software
A variety of programs that a
computer needs to function.
Definition
• Basic Input Output System (BIOS) - installed in
ROM. Enables all of the attached components to
initialise. Known as firmware.
• Operating System - MAC, Windows, Android,
iOS.
• Device Driver (Part of the OS or Installed
manually) - A software that enables hardwares
to communicate with the operating system
(Plug and play).
• Compilers - Translate high-level programming
language into machine code.
Example

12. System Software
A variety of programs that a
computer needs to function.
Definition
• Basic Input Output System (BIOS) - installed in
ROM. Enables all of the attached components to
initialise. Known as firmware.
• Operating System - MAC, Windows, Android,
iOS.
• Device Driver (Part of the OS or Installed
manually) - A software that enables hardwares
to communicate with the operating system
(Plug and play).
• Compilers - Translate high-level programming
language into machine code.
• Utilities Software - Built into the operating
system to carry out a specific task.
Example

13. System Software
A variety of programs that a
computer needs to function.
Definition
• Basic Input Output System (BIOS) - installed in
ROM. Enables all of the attached components to
initialise. Known as firmware.
• Operating System - MAC, Windows, Android,
iOS.
• Device Driver (Part of the OS or Installed
manually) - A software that enables hardwares
to communicate with the operating system
(Plug and play).
• Compilers - Translate high-level programming
language into machine code.
• Utilities Software - Built into the operating
system to carry out a specific task.
Example
• Allows software and hardware
to run without problems.
• Provides a human computer
interface.
• Control the allocation and
usage of hardware resources.
Function

14. Examples of utilities software (1)
Virus Checker - Anti Virus Software
• Offered by the operating system
• Must be constantly updated
• How they work
⚬ The software is constantly
running in the background
⚬ Check software of files before
they are run or loaded
⚬ Compare a possible virus
against a database of known
viruses
⚬ Any possible files or programs
which are infected are put into
quarantine

15. Defragmentation Software - When HDD becomes full, blocks used for files will be
scattered all over the disk surface. Data accessing will be faster if files could be
stored in contiguous sectors to reduce HDD head movements.
data
data data
data data
data
Examples of utilities software (2)

16. Device Driver
• Software that communicate
with the OS and translate data
into a format understood by a
hardware device (middle man)
• Without device drivers, a
hardware device would be
unable to work with a
computer
• As soon as a device is plugged
into a USB port, the OS looks
for appropriate device driver
Examples of utilities software (3)

17. Backup Software
• It is a good practice to use the operating
system back-up utility
• Allow a schedule for backing up files to be
made
• Total security
⚬ Working version stored in SSD/HDD
⚬ Locally backup stored in removable
SSD/HDD
⚬ Cloud Storage
• OS
⚬ Windows - File History
⚬ MacOS - TimeMachine
Examples of utilities software (4)

18. Application Software
Software that a user needs to
make use of the computer
system
Definition

19. Application Software
Software that a user needs to
make use of the computer
system
Definition Examples
• Word Processor
• Spreadsheet
• Database
• Video Editing Software
• Apps
• Music and video streaming
• GPS
• Camera facility

20. Application Software
Software that a user needs to
make use of the computer
system
Definition Examples
• Word Processor
• Spreadsheet
• Database
• Video Editing Software
• Apps
• Music and video streaming
• GPS
• Camera facility
Features
• Used to perform various
applications (apps) on a computer
• Allows a user to perform specific
tasks using the computer’s
resources

21. Eg. BIOS, OS, Device Driver, Utilities
System Software -
The Manager
Classification of Software
Responsible for managing the
hardware and other software in a
computer

22. Eg. BIOS, OS, Device Driver, Utilities
Application Software -
The Independent
Classification of Software
Allows the user to perform
different tasks using the computer
Responsible for managing the
hardware and other software in a
computer
Eg. Word Document, Spreadsheet,
Video Editing Software, Games
System Software -
The Manager

23. Operating
System
IGCSE Computer Science
Chapter 4.2

24. History
• Computer used to run only one
program at a time
• Program (written in punch card)
needs to be inserted one by one
into the computer manually
• This approach slows down
computation
• It is also difficult to integrate a
hardware (input and output
devices) with the computer
• We need a way in which program
can operate automatically
• This leads to the creation of
operating system

25. History
62,500 punch cards
= 5MB
Imagine inserting
these program one by
one into the
computer...

26. • It is a system software
• OS has the privilege of managing other
programs
• It is the first program to be launched (by
the BIOS) when a computer is turned on
• OS is an intermediaries between software
programs and hardware peripherals
(Driver)
• Stored within the SSD/HDD, loaded into
RAM when a particular action needs to be
carried out
About the Operating System

27. Main function of the operating system
Enable computer system to function correctly
Allow users to communicate with computer systems

28. 7 Main Functions Of
The Operating System

29. HCI
Human computer interface
The OS provides an interface which allow the user to communicate with the
computer.

30. HCI
Human computer interface
The OS provides an interface which allow the user to communicate with the
computer.
3 types of HCI
Command Line
Interface
• User needs to learn a
number of commands
• Direct communication
with the computer and is
not restricted to a
number of
predetermined options

31. HCI
Human computer interface
The OS provides an interface which allow the user to communicate with the
computer.
3 types of HCI
Command Line
Interface
Graphical User
Interface
• User needs to learn a
number of commands
• Direct communication
with the computer and is
not restricted to a
number of
predetermined options
• Interaction using
pictures of symbol
(instead of command)
• WIMP (Windows Icon
Menu and Pointing
Device)
• Phones touch screen
(pinch and rotate)

32. HCI
Human computer interface
The OS provides an interface which allow the user to communicate with the
computer.
3 types of HCI
Command Line
Interface
Graphical User
Interface
Voice Command
Interface
• User needs to learn a
number of commands
• Direct communication
with the computer and is
not restricted to a
number of
predetermined options
• Interaction using
pictures of symbol
(instead of command)
• WIMP (Windows Icon
Menu and Pointing
Device)
• Phones touch screen
(pinch and rotate)
• Smart Speaker (Google
Home and Amazon
Alexa)
• Virtual Assistant (Siri)

33. HCI
Compare and Contrast CLI and GUI
Command Line
Interface
• Need to learn a lot of commands
• Each command must be typed in correctly in
terms of format and spelling
• The user is in direct communication with the
computer
• Uses a small amount of computer memory

34. • It is more user-friendly; icons are used to
represent applications
• The user doesn’t need to learn any commands
HCI
Compare and Contrast CLI and GUI
Command Line
Interface
Graphical User
Interface
• Need to learn a lot of commands
• Each command must be typed in correctly in
terms of format and spelling
• Use up more computer memory than CLI
• The user is limited to icons provided on the
screen
• The user is in direct communication with the
computer
• Uses a small amount of computer memory

35. HCI
When a program is
needed, its code will be
loaded from the
Secondary Storage into
the Primary RAM, but
who does it????
MM
VON NEUMANN ARCHITECTURE
Input Output
Central Processing Unit (CPU)
Memory Unit (RAM)
ALU
CU
MAR
PC
MDR
CIR
ACC
CONTROL BUS
DATA BUS
ADDRESS BUS
Secondary Storage
(HDD, SSD, Removable Disk, CD)
Load executable
code when needed
Memory Management

36. HCI
• Track of all the memory locations
MM
VON NEUMANN ARCHITECTURE
Input Output
Central Processing Unit (CPU)
Memory Unit (RAM)
ALU
CU
MAR
PC
MDR
CIR
ACC
CONTROL BUS
DATA BUS
ADDRESS BUS
Secondary Storage
(HDD, SSD, Removable Disk, CD)
Load executable
code when needed
Memory Management
OS does it! OS will...

37. HCI
• Track of all the memory locations
• Carries out memory protection to
ensure that two competing
applications cannot use the same
memory locations at the same time
MM
VON NEUMANN ARCHITECTURE
Input Output
Central Processing Unit (CPU)
Memory Unit (RAM)
ALU
CU
MAR
PC
MDR
CIR
ACC
CONTROL BUS
DATA BUS
ADDRESS BUS
Secondary Storage
(HDD, SSD, Removable Disk, CD)
Load executable
code when needed
Memory Management
OS does it! OS will...

38. HCI
• Track of all the memory locations
• Carries out memory protection to
ensure that two competing
applications cannot use the same
memory locations at the same time
• Make sure enough hardware is
allocated to perform the necessary
process
MM
VON NEUMANN ARCHITECTURE
Input Output
Central Processing Unit (CPU)
Memory Unit (RAM)
ALU
CU
MAR
PC
MDR
CIR
ACC
CONTROL BUS
DATA BUS
ADDRESS BUS
Secondary Storage
(HDD, SSD, Removable Disk, CD)
Load executable
code when needed
Memory Management
OS does it! OS will...

39. HCI MM
Multitasking - allows the computer to carry
out more than 1 task at a time
MT
• Each of the processes will share the
hardware resources under the control
of the operating system software.
Sharing hardware resources

40. HCI MM
Multitasking - allows the computer to carry
out more than 1 task at a time
MT
• Each of the processes will share the
hardware resources under the control
of the operating system software.
• Resources are allocated to a process for a
specific time limit
• The process can be interrupted while it is
running
• The process is given a priority so it can have
resources according to its priority (the risk
here is that a low priority process could be
starved of resources)
Sharing hardware resources
Pre-emptive multitasking

41. HCI MM
Hardware Peripheral
Management
MT HPM
Meaning of peripheral devices Roles of the OS: Carry out Hardware Management
• Use device driver
⚬ Communicates with all input and output
devices
⚬ Take data from a file (defined by the
operating system) and translates it into a
format that the input/output device can
understand
• Ensures each hardware resource has a
priority so that they can be used and released
as required

42. HCI MM
User Account
Management
MT HPM UAM
A computer can have more than one user to log
into the account. Eg.
It is therefore
important that users’
data is stored in
separate parts of the
memory for security
reasons.

43. HCI MM
User Account
Management
MT HPM UAM
Role of an administrator
• Oversees the management of these user
accounts
• The administrator can create accounts, delete
user accounts and restrict user account activity
(create, edit and delete file)

44. HCI MM
File management
MT HPM UAM FM
Main tasks of file management include:
• file naming conventions which can be used i.e.
filename.docx (where the extension can
be .bat, .htm, .dbf, .txt, .xls, etc.)
• performing specific tasks (for example, create,
open, close, delete, rename, copy, and move)

45. HCI MM
File management
MT HPM UAM FM
Main tasks of file management include:
• file naming conventions which can be used i.e.
filename.docx (where the extension can
be .bat, .htm, .dbf, .txt, .xls, etc.)
• performing specific tasks (for example, create,
open, close, delete, rename, copy, and move)
• maintaining the directory structures
• ensuring memory allocation for a file by reading
it from the HDD/SSD and loading it into
memory.

46. HCI MM
Security Management
- covered more in depth in chapter 5
MT HPM UAM FM
Main tasks of security management include:
• Ensures that anti virus software (and other security software) is always up to
date, preserving the integrity, security and privacy of data
• Maintains access rights for all users
• Communicates with a firewall to check all traffic to and from the computer
• By offering the ability for the recovery of data when it has been lost or corrupted
(eg. Apple Time Machine)
SEC

47. Human Computer Interface
7 Main
Functions Of
The Operating
System
Memory Management
Multitasking
Hardware Peripheral Management
User Account Management
File Management
Security Management

48. Human Computer Interface
Memory Management
Multitasking
Hardware Peripheral Management
User Account Management
File Management
Security Management
7 functions of the OS:
HMM, How U Feeling Son?

49. EXAM QUESTION

50. EXAM QUESTION

51. Chapter 4.3
Running of
Application

52. Introducing BIOS (Basic Input/Output System)
• Known as firmware (a tangible
electronic component with
embedded software instructions,
such as a BIOS)
• The BIOS settings are stored on a
CMOS chip (complementary
metal-oxide-semiconductor)
⚬ BIOS settings would be reset if
the battery was removed or
disconnected
• Responsible for booting up the
computer by loading part of the
operating system from secondary
storage into RAM

53. Application Software Running Sequence
Power On
Hardware

54. Application Software Running Sequence
Power On
Firmware
(BIOS)
Hardware
Bios checks if every
hardware is working
fine
Loads the
BIOS
program
located in
the ROM

55. Application Software Running Sequence
Power On
Firmware
(BIOS)
Operating
System
Hardware
Bios checks if every
hardware is working
fine
BIOS loads
the
operating
system
Loads the
BIOS
program
located in
the ROM

56. Application Software Running Sequence
Power On
Firmware
(BIOS)
Operating
System
Application
Software
Hardware
Bios checks if every
hardware is working
fine
BIOS loads
the
operating
system
Loads the
BIOS
program
located in
the ROM
Operating System
takes over

57. INTERRUPT
IGCSE CS
Chapter 4.4: Software

58. DEFINITION OF
INTERRUPT
AN INTERRUPT IS WHERE A SIGNAL IS SENT
FROM A DEVICE OR A PROGRAM TO THE
OPERATING SYSTEM THAT CAUSES A
TEMPERORY STOP.

59. EXAMPLES OF AN INTERRUPT
: YOU TRY
Try to create two
folders that have
the same name
Try to perform
5/0 in your
calculator

60. OTHER EXAMPLES OF AN
INTERRUPT
A hardware fault
(Printer out of ink,
paper jam)
A timing signal
Software error

61. FUNCTION OF AN INTERRUPT
CAUSE THE CURRENT PROGRAM TO
TEMPERORILY STOP WHAT IT IS DOING SO
THAT THE OS CAN SERVICE THE INTERRUPT

62. FLOW
Device sends
an interrupt
signal
Eg.Divide by 0, keyboard key
pressed, printer error, mouse
movement

63. FLOW
Device sends
an interrupt
signal
Eg.Divide by 0, keyboard key
pressed, printer error, mouse
movement
The interrupt
is collected by
an
XX
interrupt
handler

64. VON NEUMANN ARCHITECTURE
Input Output
Central Processing Unit (CPU)
Memory Unit (RAM)
ALU
CU
MAR
PC
MDR
CIR
ACC
Secondary Storage
(HDD, SSD, Removable Disk, CD)
Load executable
code when needed
CONTROL BUS
DATA BUS
ADDRESS BUS

65. VON NEUMANN ARCHITECTURE CONTROL BUS
DATA BUS
ADDRESS BUS
IF THERE ARE SO MANY INSTRUCTIONS NEED
TO BE EXECUTED IN A SECOND, HOW DOES THE
COMPUTER DECIDE WHICH INSTRUCTION TO
EXECUTE FIRST?

66. FLOW
Device sends
an interrupt
signal
Eg.Divide by 0, keyboard key
pressed, printer error, mouse
movement
The interrupt
is being
assigned a
place in a
queue
1
2
3
I1
I2
XX
Before
1
2
3
I1
I2
XX
Part of the
Interrupt Service Routine
After
The interrupt
is collected by
an
interrupt
handler

67. FLOW
Device sends
an interrupt
signal
Priority is decided by the Operating System
The interrupt
is being
assigned a
place in a
queue
1
2
3
I1
I2
XX
Before
1
2
3
I1
I2
XX
Part of the Interrupt
Service Routine
After
Eg.Divide by 0, keyboard key
pressed, printer error, mouse
movement
Upon completing a fetch-
decode-execute cycle, the CPU
checks the priority of the next
interrupt to see if it has a
higher priority than the
current task being processed.
The interrupt
is collected by
an
interrupt
handler

68. FLOW
Device sends
an interrupt
signal
Priority is decided by the Operating System
The interrupt
is being
assigned a
place in a
queue
1
2
3
I1
I2
XX
Before
1
2
3
I1
I2
XX
Part of the Interrupt
Service Routine
After
Eg.Divide by 0, keyboard key
pressed, printer error, mouse
movement
Upon completing a fetch-
decode-execute cycle, the CPU
checks the priority of the next
interrupt to see if it has a
higher priority than the
current task being processed.
The CPU stops what it
is doing and fetches
the interrupt to the
CPU to be processed
Yes, the interrupt has
higher priority
The interrupt
is collected by
an
interrupt
handler

69. FLOW
Device sends
an interrupt
signal
Priority is decided by the Operating System
The interrupt
is being
assigned a
place in a
queue
1
2
3
I1
I2
XX
Before
1
2
3
I1
I2
XX
Part of the Interrupt
Service Routine
After
Eg.Divide by 0, keyboard key
pressed, printer error, mouse
movement
Upon completing a fetch-
decode-execute cycle, the CPU
checks the priority of the next
interrupt to see if it has a
higher priority than the
current task being processed.
No, it has lower
priority
It leaves the interrupt
in the interrupt
queue and carries on
processing
The interrupt
is collected by
an
interrupt
handler

70. FLOW
The process happens so quickly that it is
impossible for the user to notice that the
operating system has been interrupted
temperorily.
Interrupts allow computers to
carry out many tasks or to
have several windows open at
the same time
Device sends
an interrupt
signal
Priority is decided by the Operating System
The interrupt
is collected by
an interrupt
handler
The interrupt
is being
assigned a
place in a
queue
1
2
3
I1
I2
XX
Before
1
2
3
I1
I2
XX
Part of the Interrupt
Service Routine
After
Eg.Divide by 0, keyboard key
pressed, printer error, mouse
movement
Upon completing a fetch-
decode-execute cycle, the CPU
checks the priority of the next
interrupt to see if it has a
higher priority than the
current task being processed.
No, it has lower
priority
The CPU stops what it
is doing and fetches
the interrupt to the
CPU to be processed
Yes, the interrupt has
higher priority
It leaves the interrupt
in the interrupt
queue and carries on
processing

71. Hardware
Interrupt
Software
Interrupt
• Division by
zero
• Processes
attempt to
access the
same
memory
location
• Press of a
key on a
keyboard
• click of a
mouse
button

72. EXAM QUESTION

73. EXAM QUESTION

74. EXAM QUESTION

75. EXAM QUESTION

76. TYPES OF PROGRAMMING
LANGUAGES
IGCSE Computer Science
Chapter 4.4
assembly
language

77. PROGRAMMING
LANGUAGES POPULARITY
RANKING
IGCSE Computer Science
Chapter 4: Software
https://statisticstimes.com/tech/top-computer-languages.php

78. Definition of a Software
A set of instructions written in a programming
language that performs one or more tasks to tell
the computer what to do.
RECAP

79. Programming Languages Machine Code
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Codes written in any language needs to be translated to machine code before it can be
understood by a computer.
Translators

80. Programming Languages Machine Code
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Why does programmers have to code using
programming language instead of machine code

81. High-Level Programming Languages
• Contains English-like words and terms that
we use in communication and are easier
for programmers to understand

82. High-Level Programming Languages
• Contains English-like words and terms that
we use in communication and are easier
for programmers to understand
• Enable a programmer to focus on the
problem to be solved and require no
knowledge of the hardware and instruction
set of the computer that will use the
program.

83. Lets try to create 2 mini software
(Very mini) in Python
• Ask a user for his/her name,
then, print out a message to
greet the user (eg. Hello, XXX)
• Ask a user for 2 numbers
(integers), then, print out the
result of the first number minus
the second number.

84. Low-Level Programming Languages (1)
Machine Code
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
It is impossible to code in
machine code

85. Low-Level Programming Languages (2)
Assembly Language (eg. MIPS) Illustration of how it works
a0
a1
t0
2
3

86. Low-Level Programming Languages (2)
Assembly Language (eg. MIPS)
• A type of programming that
sits just above machine code
and is low-level language that
use mnemonics for its
instructions and commands.
• Mnemonic
⚬ LW - Load Word
⚬ INP - Input
⚬ RET - Return
Properties of assembly language
MEMORISE A FEW !

87. Low-Level Programming Languages (2)
Assembly Language (eg. MIPS)
• To make use of special
hardware
• Write code that doesn’t take
up much space in primary
memory
• Write code that performs a
task very quickly
Why we use assembly language

88. Differences between high-level and low-level programming languages
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Does
Harry
Eat
My
Supper

89. Differences between high-level and low-level programming languages
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Debug
Easier to debug Harder to debug

90. Differences between high-level and low-level programming languages
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Debug
Easier to debug Harder to debug
Hardware
Inefficient in hardware usage
Able to directly mainpulate
computer hardware

91. Differences between high-level and low-level programming languages
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Debug
Easier to debug Harder to debug
Hardware
Inefficient in hardware usage
Able to directly mainpulate
computer hardware
Ease
Easier to read and write by
programmers
More challenging to read and
write codes

92. Differences between high-level and low-level programming languages
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Debug
Easier to debug Harder to debug
Hardware
Inefficient in hardware usage
Able to directly mainpulate
computer hardware
Ease
Easier to read and write by
programmers
More challenging to read and
write codes
Memory
Takes up a little space in the
primary memory
Takes up a lot of memory due to
layers of abstraction

93. Differences between high-level and low-level programming languages
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Debug
Easier to debug Harder to debug
Hardware
Inefficient in hardware usage
Able to directly mainpulate
computer hardware
Ease
Easier to read and write by
programmers
More challenging to read and
write codes
Memory
Takes up a little space in the
primary memory
Takes up a lot of memory due to
layers of abstraction
Speed
Execution time is
slower
Execution time is
faster

94. EXAM QUESTION

95. EXAM QUESTION

96. EXAM QUESTION

97. EXAM QUESTION

98. EXAM QUESTION

99. EXAM QUESTION

100. EXAM QUESTION

101. EXAM QUESTION

102. TRANSLATOR
IGCSE CS
Chapter 4.5

103. Programming Languages Machine Code
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Translators

104. Translators
Machine Code
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Different programming
languages need a different
translator to be converted into
machine code
Our Focus This Week

105. Translators
Machine Code
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010
Different programming
languages need a different
translator to be converted into
machine code
Our Focus This Week

106. Translators
• Interpreter (Python)
• Compiler (C)
• Assembler (Assembly Language)
3 types of translator

107. Translators
• Interpreter (Python)
• Compiler (C)
• Assembler (Assembly Language)
• Translate codes written in various programming
languages to binary.
• Report errors in the code to the programmer.
3 types of translator
Main functions

108. Interpreter
• Interpret the code line by line in a program
• Interpreter stop the execution of the code when it detects an
error (Compiler waits until the end of the execution process
before reporting errors)
• Will not produce an executable file at the end of the process
Python Javascript

109. Interpreter
Python
Code is interpreted line by line

110. Compiler
C Programming Language
• Translates an entire program written in a high- level language (HLL) into machine
code all in one go so that it can be directly used by a computer to perform a
required task. An executable file will be produced
Compile
Running the
compiled
code

111. Compiler
C Programming Language
• Translates an entire program written in a high- level language (HLL) into machine
code all in one go so that it can be directly used by a computer to perform a
required task. An executable file will be produced
• A report of errors is produced at the end of the translation
Compile
Running the
compiled
code

112. Compiler
C Programming Language
• Translates an entire program written in a high- level language (HLL) into machine
code all in one go so that it can be directly used by a computer to perform a
required task. An executable file will be produced
• A report of errors is produced at the end of the translation
• Once a program is compiled the machine code can be used again and again to
perform the same task without re-compilation
Compile
Running the
compiled
code

113. Assembler
• Translate a program written in an assembly language into machine code
• Once a program is assembled the machine code can be used again and again to
perform the same task without re-assembly.
Assemble
r
Machine Code
0101010100101001001001
0101010100100101001001
1010101000101101010101
0101010101001010101010
1001010101001010010010
0101010101001001010010
0110101010001011010101
0101010101010010101010
1010010101010010100100
1001010101010010010100
1001101010100010110101
0101010101010100101010
101010

114. Compare and contrast the 3 translators
Compiler Interpreter Assembler
Produce executable file Produce executable file
Does not produce executable file
Compiled program is run
without the compiler
Execute a high level
programming language one
line at a time
Translate low-level
programming language into
machine code
Translate high-level
programming language into
machine code
Interpreted program cannot
run without the interpreter
Assembled program is run
without the assembler

115. Compare and contrast the 3 translators
Compiler Interpreter Assembler
Produce executable file Produce executable file
Does not produce executable file
Compiled program is run
without the compiler
Execute a high level
programming language one
line at a time
Translate low-level
programming language into
machine code
Translate high-level
programming language into
machine code
Interpreted program cannot
run without the interpreter
Assembled program is run
without the assembler

116. Interpreter Compiler
Easier for beginners as errors are
easily identified
Easier and quicker to debug and test
programs during development
A compiled program is executed in
a shorter time
Programs can take longer to
execute
It takes a longer time to write,
test and debug programs
during development

117. Integrated
Development
Environment (IDE)

118. Integrated Development
Environment (IDE)
• An IDE is an application that
programmers use to test and
develop new software
• An IDE allows a programmer
to write code in various
programming language and
smulate the running of the
code
• Eg. PythonIDE, Sublime Text,
Visual Studio Code, Pycharm

119. 7 features of an IDE

120. Code Editor
- contains
shell
7 features of an IDE
Auto
completion
- common
function
/syntax
Auto
Correction
- bracket
matching
Prettyprint
- colour
scheme,
indentation
Translator
- compiler,
interpreter
Error
Diagnostic
- pinpoints
error
Run-time
Environment
- with
debugger

121. EXAM QUESTION

122. EXAM QUESTION

123. EXAM QUESTION

124. EXAM QUESTION

125. EXAM QUESTION

126. EXAM QUESTION

127. EXAM QUESTION

128. EXAM QUESTION