Cambridge Olevel Computer Science revision notes
Join us for the "Cambridge OLevel Computer Science Revision Notes" course. Our comprehensive notes cover programming, algorithms, data representation, and more,...
Join us for the "Cambridge OLevel Computer Science Revision Notes" course. Our comprehensive notes cover programming, algorithms, data representation, and more,...
Welcome to "Cambridge OLevel Computer Science Revision Notes". This course is designed to help students excel in their Cambridge OLevel Computer Science exams. Our comprehensive revision notes cover all topics required for the Computer Science syllabus, providing a strong foundation and ensuring you are well-prepared for your exams.
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Worked Examples: Each topic includes worked examples to help you understand the application of computer science concepts.
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Lesson-9.1.4- Read, understand and complete structured query language (SQL) scripts to query data stored in a single database table. Limited to: – SELECT – FROM – WHERE – ORDER BY – SUM – COUNT • Identifying the output given by an SQL statem
Lesson-9.1.3-Understand the purpose of a primary key and identify a suitable primary key for a given database table.
Lesson-9.1.2- Suggest suitable basic data types. Including: – text/alphanumeric – character – Boolean – integer – real – date/time.
Lesson-9.1.1- Define a single-table database from given data storage requirements. Including: – fields – records – validation.
Lesson-8.1.5- Understand and use the concept of selection. Including: – IF statements – CASE statements.
Lesson-8.1.4- Complete a truth table from a: (i) problem statement (ii) logic expression (iii) logic circuit
Lesson-8.1.3- Understand and use input and output.
Lesson-8.1.2- Understand and use the basic data types. Including: – integer – real – char – string – Boolean.
Lesson-8.1.1- Declare and use variables and constants.
Lesson-8.1.6- Understand and use the concept of iteration. Including: – count-controlled loops – pre-condition loops – post-condition loops.
Lesson-8.1.7-Understand and use the concepts of totaling and counting.
Lesson-8.1.8- Understand and use the concept of string handling. Including: – length – substring – upper – lower • The first character of the string can be position zero or one.
Lesson-8.1.8- Understand and use arithmetic, logical and Boolean operators. Arithmetic, limited to: – + – – – / – * – ^ (raised to power of) – MOD – DIV • Logical, limited to: – = – < – – >= – (not equal to) • Boolean, lim
Lesson-8.1.8- Understand and use nested statements. Including nested selection and iteration • Candidates will not be required to write more than three levels of nested statements.
Lesson- 8.1.9- Understand what is meant by procedures, functions and parameters.
Lesson-8.1.10- Understand and use library routines. Including: – MOD – DIV – ROUND – RANDOM.
Lesson- 8.1.11- Including appropriate use of: – meaningful identifiers – the commenting feature provided by the programming language – procedures and functions – relevant and appropriate commenting of syntax.
Lesson-8.1.12- Understand how to create a maintainable program. Use meaningful identifiers for: – variables – constants – arrays – procedures and functions.
Lesson-8.1.13- Declare and use one-dimensional (1D) and two-dimensional (2D) arrays.
Lesson-8.1.14- Understand the use of arrays. Including the use of variables as indexes in arrays • The first index can be zero or one.
Lesson-8.1.15- Write values into and read values from an array using iteration. Including nested iteration.
Lesson-8.1.16- Understand the purpose of storing data in a file to be used by a program.
Lesson-8.1.17- Open, close and use a file for reading and writing. Including: – read and write single items of data – read and write a line of text.
Lesson-7.1.2- Understand that every computer system is made up of sub-systems, which are made up of further sub-systems.
Lesson-7.1.1- Understand the program development life cycle, limited to: analysis, design, coding and testing.
Lesson-7.1.3- Understand how a problem can be decomposed into its component parts. Including: – inputs – processes – outputs – storage.
Lesson-7.1.4- Use different methods to design and construct a solution to a problem.
Lesson-7.1.5- Explain the purpose of a given algorithm. Including: – stating the purpose of an algorithm – describing the processes involved in an algorithm.
Lesson-7.1.6- Understand standard methods of solution. Limited to: – linear search – bubble sort – totalling – counting – finding maximum, minimum and average values.
Lesson-7.1.7- Understand the need for validation checks to be made on input data and the different types of validation check. Including: – range check – length check – type check – presence check – format check – check digit – the purpose of
Lesson-7.1.8- Understand the need for verification checks to be made on input data and the different types of verification check.
Lesson-7.1.9- Suggest and apply suitable test data. Limited to: – normal – abnormal – extreme – boundary • Extreme data is the largest/smallest acceptable value • Boundary data is the largest/smallest acceptable value and the corresponding sma
Lesson-9.1.10- Complete a trace table to document a dry-run of an algorithm.
Lesson-9.1.11- Write and amend algorithms for given problems or scenarios, using: pseudocode, program code and flowcharts.
Lesson-6.1.2- Describe the advantages and disadvantages of an automated system used for a given scenario. Including scenarios from: – industry – transport – agriculture – weather – gaming – lighting – science.
Lesson-6.1.1- Describe how sensors, microprocessors and actuators can be used in collaboration to create automated systems.
Lesson-6.1.3- Understand what is meant by robotics. Robotics is a branch of computer science that incorporates the design, construction and operation of robots • Examples include factory equipment, domestic robots and drones.
Lesson-6.1.4- Describe the characteristics of a robot. Including: – a mechanical structure or framework – electrical components, such as sensors, microprocessors and actuators – programmable.
Lesson-6.1.5- Understand the roles that robots can perform and describe the advantages and disadvantages of their use. Robots can be used in areas including: – industry – transport – agriculture – medicine – domestic – entertainment.
Lesson-6.2.1- Understand what is meant by artificial intelligence (AI).
Lesson-6.2.2- Describe the main characteristics of AI as the collection of data and the rules for using that data, the ability to reason, and can include the ability to learn and adapt.
Lesson-6.2.3- Explain the basic operation and components of AI systems to simulate intelligent behaviour.
Lesson-5.1.2- Understand what is meant by a uniform resource locator (URL).
Lesson-5.1.1- Understand the difference between the internet and the world wide web.
Lesson-5.1.3- Describe the purpose and operation of hypertext transfer protocol (HTTP) and hypertext transfer protocol secure (HTTPS).
Lesson-5.1.4- Explain the purpose and functions of a web browser. The main purpose of a web browser is to render hypertext markup language (HTML) and display web pages • Functions include: – storing bookmarks and favourites – recording user history
Lesson-5.1.5- Describe how web pages are located, retrieved and displayed on a device when a user enters a URL. Including the role of: – the web browser – IP addresses – domain name server (DNS) – web server – HTML
Lesson-5.1.6- Explain what is meant by cookies and how they are used, including session cookies and persistent cookies. Cookies are used for functions, including: – saving personal details – tracking user preferences – holding items in an online sho
Lesson-5.1.7- Understand the concept of a digital currency and how digital currencies are used.
Lesson-5.1.8- Understand the process of blockchain and how it is used to track digital currency transactions.
Lesson-5.1.9- Describe the processes involved in, and the aim of carrying out, a range of cyber security threats. Including: – brute-force attack – data interception – distributed denial of service (DDoS) attack – hacking – malware (virus, worm,
Lesson-5.1.10- Explain how a range of solutions are used to help keep data safe from security threats. Including: – access levels – anti-malware including anti-virus and anti-spyware – authentication (username and password, biometrics, two-step veri
Lesson-4.1.9- Explain the role of an IDE in writing program code and the common functions IDEs provide. Including: – code editors – run-time environment – translators – error diagnostics – auto-completion – auto-correction – prettyprint.
Lesson-4.1.8- Explain the advantages and disadvantages of a compiler and an interpreter.
Lesson-4.1.7- Describe the operation of a compiler and an interpreter, including how high-level language is translated by each and how errors are reported.
Lesson-4.1.6- Understand that assembly language is a form of low-level language that uses mnemonics, and that an assembler is needed to translate an assembly language program into machine code.
Lesson-4.1.5- Explain what is meant by a high-level language and a low-level language, including the advantages and disadvantages of each
Lesson-4.1.4- Describe the role and operation of interrupts. Including: – how an interrupt is generated – how it is handled using an interrupt service routine – what happens as a result of the interrupts • Software interrupts include division by z
Lesson-4.1.3- Understand how hardware, firmware and an operating system are required to run applications software. Applications are run on the operating system • The operating system is run on the firmware • The bootloader (firmware) is run on the har
Lesson-4.1.2-Describe the role and basic functions of an operating system. Including: – managing files – handling interrupts – providing an interface – managing peripherals and drivers – managing memory – managing multitasking – providing a
Lesson-4.1.1- Describe the difference between system software and application software and provide examples of each.
Lesson-3.1.3- Understand the purpose of the components in a CPU, in a computer that has a Von Neumann architecture.
Lesson-3.1.2- Understand what is meant by a microprocessor. A microprocessor is a type of integrated circuit on a single chip.
Lesson-3.1.1- Understand the role of the central processing unit (CPU) in a computer.
Lesson-3.1.4- Describe the process of the fetch–decode–execute (FDE) cycle including the role of each component in the process.
Lesson-3.1.5- Understand what is meant by a core, cache and clock in a CPU and explain how they can affect the performance of a CPU.
Lesson-3.1.6- Understand the purpose and use of an instruction set for a CPU.
Lesson-3.1.7-Describe the purpose and characteristics of an embedded system and identify devices in which they are commonly used .
Lesson-3.1.8- Understand what is meant by an input device and why it is required. Including: – barcode scanner – digital camera – keyboard – microphone – optical mouse – QR code scanner – touch screen (resistive, capacitive and infra-red) ?
Lesson-3.1.9- Understand what is meant by an output device and why it is required. Including: – actuator – digital light processing (DLP) projector – inkjet printer – laser printer – light emitting diode (LED) screen – liquid crystal display (
Lesson-3.1.10- Understand what is meant by a sensor and the purposes of sensors. Limited to: – acoustic – accelerometer – flow – gas – humidity – infra-red – level – light – magnetic field – moisture – pH – pressure – proximity ?
Lesson-3.1.11- Identify the type of data captured by each sensor and understand when each sensor would be used, including selecting the most suitable sensor for a given context;
Lesson-3.2.1- Understand what is meant by primary storage. Primary storage is directly accessed by the CPU • Including the role of: – random access memory (RAM) – read only memory (ROM) • Including why a computer needs both RAM and ROM, and the di
Lesson-3.2.2- Understand what is meant by secondary storage. Secondary storage is not directly accessed by the CPU and is necessary for more permanent storage of data.
Lesson-3.2.3- Describe the operation of magnetic, optical and solid-state (flash memory) storage and give examples of each.
Lesson-3.2.4- Describe what is meant by virtual memory, how it is created and used and why it is necessary.
Lesson-3.2.5- Understand what is meant by cloud storage. Cloud storage can be accessed remotely in comparison to storing data locally • Physical servers and storage are needed to store data in cloud storage.
Lesson-3.2.6- Explain the advantages and disadvantages of storing data on the cloud in comparison to storing it locally.
Lesson-3.1.1- Understand that a computer needs a network interface card (NIC) to access a network.
Lesson-3.3.2- Understand what is meant by and the purpose of a media access control (MAC) address, including its structure.
Lesson-3.3.3- Understand what is meant by and the purpose of an internet protocol (IP) address.
Lesson-3.3.4- Understand that there are different types of IP address.
Lesson-3.3.5- Describe the role of a router in a network.
Lesson-2.1.9- Describe how a check digit is used to detect errors in data entry and identify examples of when a check digit is used, including international standard book numbers (ISBN) and bar codes.
Lesson-2.1.8- Describe the processes involved in each of the following error detection methods for detecting errors in data after transmission: parity check (odd and even), checksum and echo check.
Lesson-2.1.7- Understand the need to check for errors after data transmission and how these errors can occur. Errors can occur during data transmission due to interference, e.g. data loss, data gain and data change.
Lesson-2.1.6- Understand the universal serial bus (USB) interface and explain how it is used to transmit data.
Lesson-2.1.5- Explain the suitability of each method of data transmission, for a given scenario. Including the advantages and disadvantages of each method.
Lesson-2.1.4-Describe how data is transmitted from one device to another using different methods of data transmission. Including: – serial – parallel – simplex – half-duplex – full-duplex.
Lesson-2.1.3- Describe the process of packet switching. • Data is broken down into packets • Each packet could take a different route • A router controls the route a packet takes • Packets may arrive out of order • Once the last packet has arriv
Lesson-2.1.2-Describe the structure of a packet.• A packet of data contains a – packet header – payload – trailer • The packet header includes the: – destination address – packet number – originator’s address.
Lesson-2.1.1- Understand that data is broken down into packets to be transmitted.
Lesson-2.1.10 -Describe how an automatic repeat query (ARQ) can be used to establish that data is received without error.
Lesson-2.1.11- Understand the need for and purpose of encryption when transmitting data.
Lesson-2.1.12- Understand how data is encrypted using symmetric and asymmetric encryption.
Lesson-1.1.4- Understand how and why hexadecimal is used as a beneficial method of data representation.
Lesson-1.1.3- Convert between (i) positive denary and positive binary (ii) positive denary and positive hexadecimal (iii) positive hexadecimal and positive binary.
Lesson-1.1.2- Understand how and why computers use binary to represent all forms of data. Denary is a base 10 system • Binary is a base 2 system • Hexadecimal is a base 16 system.
Lesson-1.1.1- Understand how and why computers use binary to represent all forms of data.
Lesson-1.1.5- (a) Add two positive 8-bit binary integers (b) Understand the concept of overflow and why it occurs in binary addition.
Lesson-1.1.6-Perform a logical binary shift on a positive 8-bit binary integer and understand the effect this has on the positive binary integer.
Lesson-1.1.7- Use two’s complement to represent positive and negative 8-bit binary integers.
Lesson-1.1.8- Understand how and why a computer represents text and the use of character sets, including American standard code for information interchange (ASCII) and Unicode.
Lesson-1.1.9 -Understand how and why a computer represents sound, including the effects of the sample rate and sample resolution.
Lesson-1.1.10- Understand how and why a computer represents an image, including the effects of the resolution and colour depth.
Lesson-1.1.11- Understand how data storage is measured. Including: – bit – nibble – byte – kibibyte (KiB) – mebibyte (MiB) – gibibyte (GiB) – tebibyte (TiB) – pebibyte (PiB) – exbibyte (EiB) • The amount of the previous denomination pr
Lesson-1.1.12- Calculate the file size of an image file and a sound file, using information given.
Lesson-1.1.13- Understand the purpose of and need for data compression. Compression exists to reduce the size of the file • The impact of this is, e.g.: – less bandwidth required – less storage space required – shorter transmission time.
Lesson-1.1.14- Understand how files are compressed using lossy and lossless compression methods. • Lossless compression reduces the file size without permanent loss of data, e.g. run length encoding (RLE) • Lossy compression reduces the file size by p
Lesson- 10.1.1- Identify and use the standard symbols for logic gates. See section 4 for logic gate symbols.
Lesson-10.1.2- Define and understand the functions of the logic gates. Including: – NOT – AND – OR – NAND – NOR – XOR (EOR) – the binary output produced from all the possible binary inputs • NOT is a single input gate • All other gates a
Lesson-10.1.3- Use logic gates to create given logic circuits from a: (i) problem statement (ii) logic expression (iii) truth table.
Lesson-10.1.4- Complete a truth table from a: (i) problem statement (ii) logic expression (iii) logic circuit.
Lesson-10.1.5- Write a logic expression from a: (i) problem statement (ii) logic circuit (iii) truth table.