Computer Science — A-Level

Computer Science 9618 — specification explorer

All 227 specification statements from the official Cambridge International specification, as printed.

Paper/unit applicability has not been derived for this course yet — the statements below are the parsed specification, as printed.

1. Information representation

1. Data Representation

1.1.1Show understanding of binary magnitudes and the difference between binary prefixes and decimal prefixes
1.1.2Show understanding of different number systems
1.1.3Perform binary addition and subtraction
1.1.4Describe practical applications where Binary Coded Decimal (BCD) and Hexadecimal are used
1.1.5Show understanding of and be able to represent character data in its internal binary form, depending on the character set used

2. Multimedia

1.2.1Show understanding of how data for a bitmapped image are encoded
1.2.2Perform calculations to estimate the file size for a bitmap image
1.2.3Show understanding of the effects of changing elements of a bitmap image on the image quality and file size
1.2.4Show understanding of how data for a vector graphic are encoded
1.2.5Justify the use of a bitmap image or a vector graphic for a given task
1.2.6Sound
1.2.7Show understanding of how sound is represented and encoded
1.2.8Show understanding of the impact of changing the sampling rate and resolution

3. Compression

1.3.1Show understanding of the need for and examples of the use of compression
1.3.2Show understanding of lossy and lossless compression and justify the use of a method in a given situation
1.3.3Show understanding of how a text file, bitmap image, vector graphic and sound file can be compressed

2. Communication

1. Networks including the internet

2.1.1Show understanding of the purpose and benefits of networking devices
2.1.2Show understanding of the characteristics of a LAN (local area network) and a WAN (wide area network)
2.1.3Explain the client-server and peer-to-peer models of networked computers
2.1.4Show understanding of thin-client and thick-client and the differences between them
2.1.5Show understanding of the bus, star, mesh and hybrid topologies
2.1.6Show understanding of cloud computing
2.1.7Show understanding of the differences between and implications of the use of wireless and wired networks
2.1.8Describe the hardware that is used to support a LAN
2.1.9Describe the role and function of a router in a network
2.1.10Show understanding of Ethernet and how collisions are detected and avoided
2.1.11Show understanding of bit streaming
2.1.12Show understanding of the differences between the World Wide Web (WWW) and the internet
2.1.13Describe the hardware that is used to support the internet

3. Hardware

1. Computers and their components

3.1.1Show understanding of the need for input, output, primary memory and secondary (including removable) storage
3.1.2Show understanding of embedded systems
3.1.3Describe the principal operations of hardware devices
3.1.4Show understanding of the use of buffers
3.1.5Explain the differences between Random Access Memory (RAM) and Read Only Memory (ROM)
3.1.6Explain the differences between Static RAM (SRAM) and Dynamic RAM (DRAM)
3.1.7Explain the difference between Programmable ROM (PROM), Erasable Programmable ROM (EPROM) and Electrically Erasable Programmable ROM (EEPROM)
3.1.8Show an understanding of monitoring and control systems

2. Logic Gates and Logic Circuits

3.2.1Use the following logic gate symbols:
3.2.2NOT AND OR
3.2.3NAND NOR XOR
3.2.4Understand and define the functions of :
3.2.5NOT, AND, OR, NAND, NOR and XOR (EOR) gates
3.2.6Construct the truth table for each of the logic gates above
3.2.7Construct a logic circuit
3.2.8Construct a truth table
3.2.9Construct a logic expression

4. Processor Fundamentals

1. Central Processing Unit (CPU) Architecture

4.1.1Show understanding of the basic Von Neumann model for a computer system and the stored program concept
4.1.2Show understanding of the purpose and role of registers, including the difference between general purpose and special purpose registers
4.1.3Show understanding of the purpose and roles of the Arithmetic and Logic Unit (ALU), Control Unit (CU) and system clock, Immediate Access Store (IAS)
4.1.4Show understanding of how data are transferred between various components of the computer system using the address bus, data bus and control bus
4.1.5Show understanding of how factors contribute to the performance of the computer system
4.1.6Understand how different ports provide connection to peripheral devices
4.1.7Describe the stages of the Fetch-Execute (F-E) cycle
4.1.8Show understanding of the purpose of interrupts

2. Assembly Language

4.2.1Show understanding of the relationship between assembly language and machine code
4.2.2Describe the different stages of the assembly process for a two-pass assembler
4.2.3Trace a given simple assembly language program
4.2.4Show understanding that a set of instructions are grouped
4.2.5Show understanding of and be able to use different modes of addressing

3. Bit manipulation

4.3.1Show understanding of and perform binary shifts
4.3.2Show understanding of how bit manipulation can be used to monitor/control a device
4.3.3AND #n / Bn / &n Bitwise AND operation of the contents of ACC with the operand AND <address> Bitwise AND operation of the contents of ACC with the contents of <address> XOR #n / Bn / &n Bitwise XOR operation of the contents of ACC with the operand XOR <address> Bitwise XOR operation of the contents of ACC with the contents of <address> OR #n / Bn / &n Bitwise OR operation of the contents of ACC with the operand OR <address> Bitwise OR operation of the contents of ACC with the contents of <address> LSL #n Bits in ACC are shifted logically n places to the left. Zeros are introduced on the right hand end LSR #n Bits in ACC are shifted logically n places to the right. Zeros are introduced on the left hand end <label>: <opcode> <operand> Labels an instruction <label>: <data> Gives a symbolic address <label> to the memory location with contents <data>
4.3.4All questions will assume there is only one general purpose register available (Accumulator) ACC denotes Accumulator IX denotes Index Register <address> can be an absolute or symbolic address # denotes a denary number, e.g. #123 B denotes a binary number, e.g. B01001010 & denotes a hexadecimal number, e.g. &4A

5. System Software

1. Operating Systems

5.1.1Explain why a computer system requires an Operating System (OS)
5.1.2Explain the key management tasks carried out by the Operating System
5.1.3Show understanding of the need for typical utility software provided with an Operating System
5.1.4Show understanding of program libraries

2. Language Translators

5.2.1Show understanding of the need for:
5.2.2assembler software for the translation of an assembly language program
5.2.3a compiler for the translation of a high-level language program
5.2.4an interpreter for translation and execution of a high-level language program
5.2.5Explain the benefits and drawbacks of using either a compiler or interpreter and justify the use of each
5.2.6Show awareness that high-level language programs may be partially compiled and partially interpreted, such as Java (console mode)
5.2.7Describe features found in a typical Integrated Development Environment (IDE)

6. Security, privacy and data integrity

1. Data Security

6.1.1Explain the difference between the terms security, privacy and integrity of data
6.1.2Show appreciation of the need for both the security of data and the security of the computer system
6.1.3Describe security measures designed to protect computer systems, ranging from the stand-alone PC to a network of computers
6.1.4Show understanding of the threats to computer and data security posed by networks and the internet
6.1.5Describe methods that can be used to restrict the risks posed by threats
6.1.6Describe security methods designed to protect the security of data

2. Data Integrity

6.2.1Describe how data validation and data verification help protect the integrity of data
6.2.2Describe and use methods of data validation
6.2.3Describe and use methods of data verification during data entry and data transfer

7. Ethics and Ownership

1. Ethics and Ownership

7.1.1Show understanding of the need for and purpose of ethics as a computing professional
7.1.2Show understanding of the need to act ethically and the impact of acting ethically or unethically for a given situation
7.1.3Show understanding of the need for copyright legislation
7.1.4Show understanding of the different types of software licencing and justify the use of a licence for a given situation
7.1.5Show understanding of Artificial Intelligence (AI)

8. Databases

1. Database Concepts

8.1.1Show understanding of the limitations of using a file- based approach for the storage and retrieval of data
8.1.2Describe the features of a relational database that address the limitations of a file-based approach
8.1.3Show understanding of and use the terminology associated with a relational database model
8.1.4Use an entity-relationship (E-R) diagram to document a database design
8.1.5Show understanding of the normalisation process
8.1.6Explain why a given set of database tables are, or are not, in 3NF
8.1.7Produce a normalised database design for a description of a database, a given set of data, or a given set of tables

2. Database Management Systems (DBMS)

8.2.1Show understanding of the features provided by a Database Management System (DBMS) that address the issues of a file based approach
8.2.2Show understanding of how software tools found within a DBMS are used in practice

3. Data Definition Language (DDL) and Data Manipulation Language (DML)

8.3.1Show understanding that the DBMS carries out all creation / modification of the database structure using its Data Definition Language (DDL)
8.3.2Show understanding that the DBMS carries out all queries and maintenance of data using its DML
8.3.3Show understanding that the industry standard for both DDL and DML is Structured Query Language
8.3.4Understand given SQL (DDL) statements and be able to write simple SQL (DDL) statements using a sub-set of statements

9. Algorithm Design and Problem-solving

1. Computational Thinking Skills

9.1.1Show an understanding of abstraction
9.1.2Describe and use decomposition

2. Algorithms

9.2.1Show understanding that an algorithm is a solution to a problem expressed as a sequence of defined steps
9.2.2Use suitable identifier names for the representation of data used by a problem and represent these using an identifier table
9.2.3Write pseudocode that contains input, process and output
9.2.4Write pseudocode using the three basic constructs of sequence, selection and iteration (repetition)
9.2.5Document a simple algorithm using a structured English description, a flowchart or pseudocode
9.2.6Write pseudocode from:
9.2.7a structured English description
9.2.8a flowchart
9.2.9Draw a flowchart from:
9.2.10a structured English description
9.2.11pseudocode

10. Data Types and Structures

1. Data Types and Records

10.1.1Select and use appropriate data types for a problem solution
10.1.2Show understanding of the purpose of a record structure to hold a set of data of different data types under one identifier

2. Arrays

10.2.1Use the technical terms associated with arrays
10.2.2Select a suitable data structure (1D or 2D array) to use for a given task
10.2.3Write pseudocode for 1D and 2D arrays
10.2.4Write pseudocode to process array data

3. Files

10.3.1Show understanding of why files are needed
10.3.2Write pseudocode to handle text files that consist of one or more lines

4. Introduction to Abstract Data Types (ADT)

10.4.1Show understanding that an ADT is a collection of data and a set of operations on those data
10.4.2Show understanding that a stack, queue and linked list are examples of ADTs
10.4.3Use a stack, queue and linked list to store data
10.4.4Describe how a queue, stack and linked list can be implemented using arrays

11. Programming

1. Programming Basics

11.1.1Implement and write pseudocode from a given design presented as either a program flowchart or structured English
11.1.2Write pseudocode statements for:
11.1.3the declaration and initialisation of constants
11.1.4the declaration of variables
11.1.5the assignment of values to variables
11.1.6expressions involving any of the arithmetic or logical operators input from the keyboard and output to the console
11.1.7Use built-in functions and library routines

2. Constructs

11.2.1Use pseudocode to write:
11.2.2an ‘IF’ statement including the ‘ELSE’ clause and nested IF statements
11.2.3a ‘CASE’ structure
11.2.4a ‘count-controlled’ loop:
11.2.5a ‘post-condition’ loop
11.2.6a ‘pre-condition’ loop
11.2.7Justify why one loop structure may be better suited to solve a problem than the others

3. Structured Programming

11.3.1Define and use a procedure
11.3.2Explain where in the construction of an algorithm it would be appropriate to use a procedure
11.3.3Use parameters
11.3.4Define and use a function
11.3.5Explain where in the construction of an algorithm it is appropriate to use a function
11.3.6Use the terminology associated with procedures and functions
11.3.7Write efficient pseudocode

12. Software Development

1. Program Development Life cycle

12.1.1Show understanding of the purpose of a development life cycle
12.1.2Show understanding of the need for different development life cycles depending on the program being developed
12.1.3Describe the principles, benefits and drawbacks of each type of life cycle
12.1.4Show understanding of the analysis, design, coding, testing and maintenance stages in the program development life cycle

2. Program Design

12.2.1Use a structure chart to decompose a problem into sub-tasks and express the parameters passed between the various modules / procedures / functions which are part of the algorithm design
12.2.2Show understanding of the purpose of state-transition diagrams to document an algorithm

3. Program Testing and Maintenance

12.3.1Show understanding of ways of exposing and avoiding faults in programs
12.3.2Locate and identify the different types of errors
12.3.3Correct identified errors
12.3.4Show understanding of the methods of testing available and select appropriate data for a given method
12.3.5Show understanding of the need for a test strategy and test plan and their likely contents
12.3.6Choose appropriate test data for a test plan
12.3.7Show understanding of the need for continuing maintenance of a system and the differences between each type of maintenance
12.3.8Analyse an existing program and make amendments to enhance functionality

13. Data Representation

1. User-defined data types

13.1.1Show understanding of why user-defined types are necessary
13.1.2Define and use non-composite types
13.1.3Define and use composite data types
13.1.4Choose and design an appropriate user-defined data type for a given problem

2. File organisation and access

13.2.1Show understanding of the methods of file organisation and select an appropriate method of file organisation and file access for a given problem
13.2.2Show understanding of methods of file access
13.2.3Show understanding of hashing algorithms

3. Floating-point numbers, representation and manipulation

13.3.1Describe the format of binary floating-point real numbers
13.3.2Convert binary floating-point real numbers into denary and vice versa
13.3.3Normalise floating-point numbers
13.3.4Show understanding of the consequences of a binary representation only being an approximation to the real number it represents (in certain cases)
13.3.5Show understanding that binary representations can give rise to rounding errors

14. Communication and internet technologies

1. Protocols

14.1.1Show understanding of why a protocol is essential for communication between computers
14.1.2Show understanding of how protocol implementation can be viewed as a stack, where each layer has its own functionality
14.1.3Show understanding of the TCP / IP protocol suite
14.1.4Show understanding of protocols (HTTP, FTP, POP3, IMAP, SMTP, BitTorrent) and their purposes

2. Circuit switching, packet switching

14.2.1Show understanding of circuit switching
14.2.2Show understanding of packet switching

15. Hardware and Virtual Machines

1. Processors, Parallel Processing and Virtual Machines

15.1.1Show understanding of Reduced Instruction Set Computers (RISC) and Complex Instruction Set Computers (CISC) processors
15.1.2Show understanding of the importance / use of pipelining and registers in RISC processors
15.1.3Show understanding of the four basic computer architectures
15.1.4Show understanding of the characteristics of massively parallel computers
15.1.5Show understanding of the concept of a virtual machine

2. Boolean Algebra and Logic Circuits

15.2.1Produce truth tables for logic circuits including half adders and full adders
15.2.2Show understanding of a flip-flop (SR, JK)
15.2.3Show understanding of Boolean algebra
15.2.4Show understanding of Karnaugh maps (K-map)

16. System Software

1. Purposes of an Operating System (OS)

16.1.1Show understanding of how an OS can maximise the use of resources
16.1.2Describe the ways in which the user interface hides the complexities of the hardware from the user
16.1.3Show understanding of process management
16.1.4Show understanding of virtual memory, paging and segmentation for memory management

2. Translation Software

16.2.1Show understanding of how an interpreter can execute programs without producing a translated version
16.2.2Show understanding of the various stages in the compilation of a program
16.2.3Show understanding of how the grammar of a language can be expressed using syntax diagrams or Backus-Naur Form (BNF) notation
16.2.4Show understanding of how Reverse Polish Notation (RPN) can be used to carry out the evaluation of expressions

17. Security

1. Encryption, Encryption Protocols and Digital certificates

17.1.1Show understanding of how encryption works
17.1.2Show awareness of the Secure Socket Layer (SSL)/ Transport Layer Security (TLS)
17.1.3Show understanding of digital certification

18. Artificial Intelligence (AI)

1. Artificial Intelligence (AI)

18.1.1Show understanding of how graphs can be used to aid Artificial Intelligence (AI)
18.1.2Show understanding of how artificial neural networks have helped with machine learning
18.1.3Show understanding of Deep Learning, Machine Learning and Reinforcement Learning and the reasons for using these methods.
18.1.4Show understanding of back propagation of errors and regression methods in machine learning

19. Computational thinking and Problem-solving

1. Algorithms (19.1)

19.1.1Show understanding of linear and binary searching methods
19.1.2Show understanding of insertion sort and bubble sort methods
19.1.3Show understanding of and use Abstract Data Types (ADT)
19.1.4Show how it is possible for ADTs to be implemented from another ADT
19.1.5Show understanding that different algorithms which perform the same task can be compared by using criteria (e.g. time taken to complete the task and memory used)

2. Recursion

19.2.1Show understanding of recursion
19.2.2Show awareness of what a compiler has to do to translate recursive programming code

20. Further Programming

1. Programming Paradigms

20.1.1Understanding what is meant by a programming paradigm
20.1.2Show understanding of the characteristics of a number of programming paradigms:
20.1.3Low-level
20.1.4Imperative (Procedural)
20.1.5Object Oriented
20.1.6Declarative

2. File Processing and Exception Handling

20.2.1Write code to perform file-processing operations
20.2.2Show understanding of an exception and the importance of exception handling
20.2.3Teacher guidance Equipment and facilities Computer science is a practical subject and the Cambridge AS and A Level syllabus places emphasis on the use of procedural high-level programming languages. Centres must ensure that their equipment and facilities are adequate for candidates to be able to satisfy the requirements of the syllabus. The hardware facilities needed will depend on the number of candidates, but should be sufficient for all candidates to have enough time to practise their programming skills.
20.2.4Hardware Candidates need to have access to a system with direct-access file capability on backing store and hard-copy facilities.
20.2.5Software Candidates should have experience of using a high-level programming language, chosen by the centre, from the following list:
20.2.6Java (console mode)
20.2.7Visual Basic (console mode)
20.2.8Python (console mode).
20.2.9Books The British Computer Society (BCS) book list for schools and colleges are suitable for use as reference. Teachers will need to consult several books to cover the whole syllabus adequately. There is a suggested book list on our website.
20.2.10Practical skills Computing is a practical subject and a range of practical exercises should supplement the study of most parts of the syllabus.
20.2.11It is important that centres encourage candidates, as early as possible in the course, to develop a systematic approach to practical problem-solving using appropriate resources.