IGCSE / CAIE Computer Science (0478)

Table of content

Link to Cambridge:

 https://www.cambridgeinternational.org/programmes-and-qualifications/cambridge-igcse-computer-science-0478/ 

Key Benefits

Computer Science provides an ideal foundation in computer science. Learners gain confidence in computational thinking and programming, an appreciation of automated and emerging technologies and the benefits of their use. They develop an understanding of the main principles of problem-solving by creating computer-based solutions using algorithms and a high-level programming language. Learners also develop a range of technical skills including the ability to test effectively and to evaluate solutions. 

I feel strongly that ICT (Information and Communication Technology) and Computer Science knowledge are indispensable in our rapidly evolving world. They hold the key to unlocking endless possibilities. 

Assessment Tips

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Chapter 1 Data representation

Why do computers work in binary? 

• Computer is a digital device. 

• Data is processed in a computer by using logic gates

• Logic gates only have two states (0 or 1)

~Text, sound and images

Recognized the pattern: Noticed that the numbers in the code are all between 32 and 126

Map each number to its corresponding ASCII character

Amplitude is the height of the wave.

Frequency is the number of cycle of the sound wave.

https://www.w3schools.com/colors/colors_picker.asp  

~Data storage and file compression

WebP is a modern image format that provides superior lossless and lossy compression for images on the web.  WebP lossless images are 26% smaller in size compared to PNGs. WebP lossy images are 25-34% smaller than comparable JPEG images at equivalent Structural Similarity Index (SSIM) quality index

Chapter 2 Data Transmission

2.2 Methods of error detection

A check digit is used to check whether data is correct when entered into the system.

− Data is input with check digit

− A calculation is performed on the (inputted) data 

− The calculated digit is compared to a stored value

− If it matches, the data entered is correct

− If it does not match, the data entered is incorrect

Encryption

Public key: https://isomer-user-content.by.gov.sg/36/9daf514a-415a-4aba-8bd4-c06f7a01696d/PGP-PUBLIC-KEY-BLOCK.pdf 

Chapter 3 Hardware

3.1 Computer Architecture

The width of the data bus is important; the wider the bus the larger the word length that can be transported. Larger word lengths can improve the computer’s overall performance.

Cache – is temporary memory used to hold frequently used data/instructions by the CPU thereby increasing CPU performance. More generally, cache means any area of storage used to quickly access frequently-used data

Core – a unit on a CPU made up of an ALU, control unit and registers; a CPU may contain a number of cores 

Instruction set is the complete set of machine code instructions used a particular microprocessor

3.2 Input and output devices

https://products.aspose.app/barcode/generate 

https://online-barcode-reader.inliteresearch.com/ 

Adobe Express - QR Code Generator 

ipad uses Capacitive Touch Screens  https://itstillworks.com/kind-touch-technology-iphone-use-18254.html 

Inkjet Printer

Laser Printer

Internal secondary storage

• Hard disk drive (HDD)

• Solid state drive (SSD)

https://www.bbc.co.uk/bitesize/guides/z67j2nb/revision/3 

https://compscistation.com/magnetic-tape-storage-advantages-and-disadvantages/ 

Optical media are storage devices that uses light based technology. 

Example of optical media:

• CD

• DVD

• Blu ray

Chapter 4 Software

https://scratch.mit.edu/ 

High-level programming languages are 

• portable and can be used on different types of computer

• easier to:

  • read and understand as the language used is closer to English

  • write in a shorter time

  • debug at the development stage

  • maintain once it is implemented

Low-level languages can refer to machine code, or assembly language

Chapter 5 The internet and its uses

Websites can be created using HTML structure and presentation. 

The browser interprets the HTML, which is used to structure content, and then displays the information on the user’s computer. Example; list, heading and subheadings

Presentaion refer to the style related to the presentation of the web page. Example, colour, borders.

Informatics Students & Professionals | Facebook 

~ Cyber Security

National Cyber Security Agency https://www.nacsa.gov.my/ 

Cyber Security Agency of Singapore (CSA) https://www.csa.gov.sg/ 

In a Brute Force Attack, the hacker tries to crack your password, systematically try all the different combinations of letters, numbers and other symbols until eventually they find your password.

Check your password strength at  https://ihp.csa.gov.sg/password-checker 

~ Phishing

What is a Firewall – Microsoft 365 

Chapter 6 Automated and emerging technologies

https://chat.openai.com/chat 

 https://www.elementsofai.com/ 

Chapter 7 Algorithm design and problem solving

Linear search, also known as sequential search, is a simple search algorithm used to find a specific target value within a list or array. It works by sequentially checking each element in the list until the target value is found or the entire list is traversed.

Boundary data is the largest / smallest possible value.

To do a boundary test: choose the largest or smallest possible value & another out-of-range value

Chapter 8 Programming Concepts

Procedure is a set of programming statements grouped together under a single name that can be called to perform a task at any point in a program.

Function is a set of programming statements grouped together under a single name that can be called to perform a task at any point in a program. In contrast to a procedure, a function will return a value back to the main program.

Parameters are the variables that store the values of the arguments passed to a procedure or function. Some but not all procedures and functions will have parameters

A global variable can be used by any part of a program – its scope covers the whole program.

A local variable can only be used by the part of the program it has been declared in – its scope is restricted to that part of the program.

» MOD – returns remainder of a division

» DIV – returns the quotient (i.e. the whole number part) of a division

» ROUND – returns a value rounded to a given number of decimal places

» RANDOM – returns a random number.

Chapter 9 Databases

Primary key is use to identify a record.  Primary key is unique and cannot be null (empty)

SQL stands for Structured Query Language; is a standard language used to interact with and manipulate databases, particularly relational databases.

Key Features and Uses of SQL

• SQL is widely used for various database operations, including:

• Querying Data: SQL can execute queries to retrieve data from a database.

• Inserting Records: SQL can insert new records into a database.

• Updating Records: SQL can update existing records in a database.

• Deleting Records: SQL can delete records from a database.

• Creating Databases and Tables: SQL can create new databases and tables.

• Managing Permissions: SQL can set permissions on tables, procedures, and views.

Only the SELECT and FROM clauses are mandatory in an SQL script. All other clauses are optional.

Useful Link

SQL Tutorial https://www.w3schools.com/sql/default.asp 

Chapter 10 Boolean logic

CircuitVerse - Digital Circuit Simulator online 

At the end of every chapter, there is a list of key terms for the chapter

Topical Quiz