IB Computer Science HL

Welcome

Computer science requires an understanding of the fundamental concepts of computational thinking as well as knowledge of how computers and other digital devices operate.

The Diploma Programme computer science course is engaging, accessible, inspiring and rigorous. It has the following characteristics.

• draws on a wide spectrum of knowledge
• enables and empowers innovation, exploration and the acquisition of further knowledge
• interacts with and influences cultures, society and how individuals and societies behave
• raises ethical issues
• is underpinned by computational thinking.

Computational thinking involves the ability to:

• think procedurally, logically, concurrently, abstractly, recursively and think ahead
• utilize an experimental and inquiry-based approach to problem-solving
• develop algorithms and express them clearly
• appreciate how theoretical and practical limitations affect the extent to which problems can be solved computationally.

During the course the student will develop computational solutions. This will involve the ability to:

• identify a problem or unanswered question
• design, prototype and test a proposed solution
• liaise with clients to evaluate the success of the proposed solution and make recommendations for future developments.

Computer science has links with subjects outside of group 4, notably information technology in a global society (ITGS), but it should be noted that there are clear differences between the subjects.

Standards

These are the standards we will address in this course. There are three levels of knowing for each standard.

Assessment objective 1: classify, define, draw, label, list, state

Assessment objective 2: annotate, apply, calculate, describe, design, distinguish, estimate, identify, outline, present, trace

Assessment objective 3: analyse, comment, compare, compare and contrast, construct, contrast, deduce, demonstrate, derive, determine, discuss, evaluate, examine, explain, formulate, interpret, investigate, justify, predict, sketch, suggest, to what extent

Topic 1 System fundamentals

• 1.1.1 Identify the context for which a new system is planned. Level: 2
• 1.1.2 Describe the need for change management. Level: 2
• 1.1.3 Outline compatibility issues resulting from situations including legacy systems or business mergers. Level: 2
• 1.1.4 Compare the implementation of systems using a client’s hardware with hosting systems remotely. Level: 3
• 1.1.5 Evaluate alternative installation processes. Level: 3
• 1.1.6 Discuss problems that may arise as a part of data migration. Level: 3
• 1.1.7 Suggest various types of testing. Level: 3
• 1.1.8 Describe the importance of user documentation. Level: 2
• 1.1.9 Evaluate different methods of providing user documentation. Level: 3
• 1.1.10 Evaluate different methods of delivering user training. Level: 3
• 1.1.11 Identify a range of causes of data loss. Level: 2
• 1.1.12 Outline the consequences of data loss in a specified situation. Level: 2
• 1.1.13 Describe a range of methods that can be used to prevent data loss. Level: 2
• 1.1.14 Describe strategies for managing releases and updates. Level: 2
• 1.2.1 Define the terms: hardware, software, peripheral, network, human resources. Level: 1
• 1.2.2 Describe the roles that a computer can take in a networked world. Level: 2
• 1.2.3 Discuss the social and ethical issues associated with a networked world. Level: 3
• 1.2.4 Identify the relevant stakeholders when planning a new system. Level: 2
• 1.2.5 Describe methods of obtaining requirements from stakeholders. Level: 2
• 1.2.6 Describe appropriate techniques for gathering the information needed to arrive at a workable solution. Level: 2
• 1.2.7 Construct suitable representations to illustrate system requirements. Level: 3
• 1.2.8 Describe the purpose of prototypes to demonstrate the proposed system to the client. Level: 2
• 1.2.9 Discuss the importance of iteration during the design process. Level: 3
• 1.2.10 Explain the possible consequences of failing to involve the end-user in the design process. Level: 3
• 1.2.11 Discuss the social and ethical issues associated with the introduction of new IT systems. Level: 3
• 1.2.12 Define the term usability. Level: 1
• 1.2.13 Identify a range of usability problems with commonly used digital devices. Level: 2
• 1.2.14 Identify methods that can be used to improve the accessibility of systems. Level: 2
• 1.2.15 Identify a range of usability problems that can occur in a system. Level: 2
• 1.2.16 Discuss the moral, ethical, social, economic and environmental implications of the interaction between humans and machines. Level: 3

Topic 2 Computer Organization

• 2.1.1 Outline the architecture of the central processing unit (CPU) and the functions of the arithmetic logic unit (ALU) and the control unit (CU) and the registers within the CPU. Level: 2
• 2.1.2 Describe primary memory. Level: 2
• 2.1.3 Explain the use of cache memory. Level: 3
• 2.1.4 Explain the machine instruction cycle. Level: 3
• 2.1.5 Identify the need for persistent storage. Level: 2
• 2.1.6 Describe the main functions of an operating system. Level: 2
• 2.1.7 Outline the use of a range of application software. Level: 2
• 2.1.8 Identify common features of applications. Level: 2
• 2.1.9 Define the terms: bit, byte, binary, denary/decimal, hexadecimal. Level: 1
• 2.1.10 Outline the way in which data is represented in the computer. Level: 2
• 2.1.11 Define the Boolean operators: AND, OR, NOT, NAND, NOR and XOR. Level: 1
• 2.1.12 Construct truth tables using the above operators. Level: 3
• 2.1.13 Construct a logic diagram using AND, OR, NOT, NAND, NOR and XOR gates. Level: 3

Topic 3 Networks

• 3.1.1 Identify different types of networks. Level: 2
• 3.1.2 Outline the importance of standards in the construction of networks. Level: 2
• 3.1.3 Describe how communication over networks is broken down into different layers. Level: 2
• 3.1.4 Identify the technologies required to provide a VPN. Level: 2
• 3.1.5 Evaluate the use of a VPN. Level: 3
• 3.1.6 Define the terms: protocol, data packet. Level: 1
• 3.1.7 Explain why protocols are necessary. Level: 3
• 3.1.8 Explain why the speed of data transmission across a network can vary. Level: 3
• 3.1.9 Explain why compression of data is often necessary when transmitting across a network. Level: 3
• 3.1.10 Outline the characteristics of different transmission media. Level: 2
• 3.1.11 Explain how data is transmitted by packet switching. Level: 3
• 3.1.12 Outline the advantages and disadvantages of wireless networks. Level: 2
• 3.1.13 Describe the hardware and software components of a wireless network. Level: 2
• 3.1.14 Describe the characteristics of wireless networks. Level: 2
• 3.1.15 Describe the different methods of network security. Level: 2
• 3.1.16 Evaluate the advantages and disadvantages of each method of network security. Level: 3

Topic 4 Computational thinking, problem-solving and programming

• 4.1.1 Identify the procedure appropriate to solving a problem. Level: 2
• 4.1.2 Evaluate whether the order in which activities are undertaken will result in the required outcome. Level: 3
• 4.1.3 Explain the role of sub-procedures in solving a problem. Level: 3
• 4.1.4 Identify when decision-making is required in a specified situation. Level: 2
• 4.1.5 Identify the decisions required for the solution to a specified problem. Level: 2
• 4.1.6 Identify the condition associated with a given decision in a specified problem. Level: 2
• 4.1.7 Explain the relationship between the decisions and conditions of a system. Level: 3
• 4.1.8 Deduce logical rules for real-world situations. Level: 3
• 4.1.9 Identify the inputs and outputs required in a solution. Level: 2
• 4.1.10 Identify pre-planning in a suggested problem and solution. Level: 2
• 4.1.11 Explain the need for pre-conditions when executing an algorithm. Level: 3
• 4.1.12 Outline the pre- and post-conditions to a specified problem. Level: 2
• 4.1.13 Identify exceptions that need to be considered in a specified problem solution. Level: 2
• 4.1.14 Identify the parts of a solution that could be implemented concurrently. Level: 2
• 4.1.15 Describe how concurrent processing can be used to solve a problem. Level: 2
• 4.1.16 Evaluate the decision to use concurrent processing in solving a problem. Level: 3
• 4.1.17 Identify examples of abstraction. Level: 2
• 4.1.18 Explain why abstraction is required in the derivation of computational solutions for a specified situation. Level: 3
• 4.1.19 Construct an abstraction from a specified situation. Level: 3
• 4.1.20 Distinguish between a real-world entity and its abstraction. Level: 2
• 4.2.1 Describe the characteristics of standard algorithms on linear arrays. Level: 2
• 4.2.2 Outline the standard operations of collections. Level: 2
• 4.2.3 Discuss an algorithm to solve a specific problem. Level: 3
• 4.2.4 Analyse an algorithm presented as a flow chart. Level: 3
• 4.2.5 Analyse an algorithm presented as pseudocode. Level: 3
• 4.2.6 Construct pseudocode to represent an algorithm. Level: 3
• 4.2.7 Suggest suitable algorithms to solve a specific problem. Level: 3
• 4.2.8 Deduce the efficiency of an algorithm in the context of its use. Level: 3
• 4.2.9 Determine the number of times a step in an algorithm will be performed for given input data. Level: 3
• 4.3.1 State the fundamental operations of a computer. Level: 1
• 4.3.2 Distinguish between fundamental and compound operations of a computer. Level: 2
• 4.3.3 Explain the essential features of a computer language. Level: 3
• 4.3.4 Explain the need for higher level languages. Level: 3
• 4.3.5 Outline the need for a translation process from a higher level language to machine executable code. Level: 2
• 4.3.6 Define the terms: variable, constant, operator, object. Level: 1
• 4.3.7 Define common operators. Level: 1
• 4.3.8 Analyse the use of variables, constants and operators in algorithms. Level: 3
• 4.3.9 Construct algorithms using loops, branching. Level: 3
• 4.3.10 Describe the characteristics and applications of a collection. Level: 2
• 4.3.11 Construct algorithms using the access methods of a collection. Level: 3
• 4.3.12 Discuss the need for sub-programmes and collections within programmed solutions. Level: 3
• 4.3.13 Construct algorithms using pre- defined sub-programmes, one- dimensional arrays and/or collections. Level: 3

Topic 5 Abstract data structures

• 5.1.1 Identify a situation that requires the use of recursive thinking. Level: 2
• 5.1.2 Identify recursive thinking in a specified problem solution. Level: 2
• 5.1.3 Trace a recursive algorithm to express a solution to a problem. Level: 2
• 5.1.4 Describe the characteristics of a two- dimensional array. Level: 2
• 5.1.5 Construct algorithms using two- dimensional arrays. Level: 3
• 5.1.6 Describe the characteristics and applications of a stack. Level: 2
• 5.1.7 Construct algorithms using the access methods of a stack. Level: 3
• 5.1.8 Describe the characteristics and applications of a queue. Level: 2
• 5.1.9 Construct algorithms using the access methods of a queue. Level: 3
• 5.1.10 Explain the use of arrays as static stacks and queues. Level: 3
• 5.1.11 Describe the features and characteristics of a dynamic data structure. Level: 2
• 5.1.12 Describe how linked lists operate logically. Level: 2
• 5.1.13 Sketch linked lists (single, double and circular). Level: 3
• 5.1.14 Describe how trees operate logically (both binary and non-binary). Level: 2
• 5.1.15 Define the terms: parent, left-child, right-child, subtree, root and leaf. Level: 1
• 5.1.16 State the result of inorder, postorder and preorder tree traversal. Level: 1
• 5.1.17 Sketch binary trees. Level: 3
• 5.1.18 Define the term dynamic data structure. Level: 1
• 5.1.19 Compare the use of static and dynamic data structures. Level: 3
• 5.1.20 Suggest a suitable structure for a given situation. Level: 3

Topic 6—Resource management

• 6.1.1 Identify the resources that need to be managed within a computer system. Level: 2
• 6.1.2 Evaluate the resources available in a variety of computer systems. Level: 3
• 6.1.3 Identify the limitations of a range of resources in a specified computer system. Level: 2
• 6.1.4 Describe the possible problems resulting from the limitations in the resources in a computer system. Level: 2
• 6.1.5 Explain the role of the operating system in terms of managing memory, peripherals and hardware interfaces. Level: 3
• 6.1.7 Outline OS resource management techniques: scheduling, policies, multitasking, virtual memory, paging, interrupt, polling. Level: 2
• 6.1.8 Discuss the advantages of producing a dedicated operating system for a device. Level: 3
• 6.1.9 Outline how an operating system hides the complexity of the hardware from users and applications. Level: 2

Topic 7—Control

• 7.1.1 Discuss a range of control systems. Level: 3
• 7.1.2 Outline the uses of microprocessors and sensor input in control systems. Level: 2
• 7.1.3 Evaluate different input devices for the collection of data in specified situations. Level: 3
• 7.1.4 Explain the relationship between a sensor, the processor and an output transducer. Level: 3
• 7.1.5 Describe the role of feedback in a control system. Level: 2
• 7.1.6 Discuss the social impacts and ethical considerations associated with the use of embedded systems. Level: 3
• 7.1.7 Compare a centrally controlled system with a distributed system. Level: 3
• 7.1.8 Outline the role of autonomous agents acting within a larger system. Level: 2

C—Web science

• C.1.1 Distinguish between the internet and World Wide Web (web). Level: 2
• C.1.2 Describe how the web is constantly evolving. Level: 2
• C.1.3 Identify the characteristics of the following: HTTP, HTTPS, HTML, URL, XML, XSLT, CSS. Level: 2
• C.1.4 Identify the characteristics of a uniform resource identifier (URI) URL. Level: 2
• C.1.5 Describe the purpose of a URL. Level: 2
• C.1.6 Describe how a domain name server functions. Level: 2
• C.1.7 Identify the characteristics of the internet protocol (IP) transmission control protocol (TCP) file transfer protocol (FTP). Level: 2
• C.1.8 Outline the different components of a web page. Level: 2
• C.1.9 Explain the importance of protocols and standards on the web. Level: 3
• C.1.10 Describe the different types of web page. Level: 2
• C.1.11 Explain the differences between a static web page and a dynamic web page. Level: 3
• C.1.12 Explain the functions of a browser. Level: 3
• C.1.13 Evaluate the use of client-side scripting and server-side scripting in web pages. Level: 3
• C.1.14 Describe how web pages can be connected to underlying data sources. Level: 2
• C.1.15 Describe the function of the common gateway interface (CGI). Level: 2
• C.1.16 Evaluate the structure of different types of web pages. Level: 3
• C.2.1 Define the term search engine. Level: 1
• C.2.2 Distinguish between the surface web and the deep web. Level: 2
• C.2.3 Outline the principles of searching algorithms used by search engines. Level: 2
• C.2.4 Describe how a web crawler functions. Level: 2
• C.2.5 Discuss the relationship between data in a meta-tag and how it is accessed by a web crawler. Level: 3
• C.2.6 Discuss the use of parallel web crawling. Level: 3
• C.2.7 Outline the purpose of web-indexing in search engines. Level: 2
• C.2.8 Suggest how web developers can create pages that appear more prominently in search engine results. Level: 3
• C.2.9 Describe the different metrics used by search engines. Level: 2
• C.2.10 Explain why the effectiveness of a search engine is determined by the assumptions made when developing it. Level: 3
• C.2.11 Discuss the use of white hat and black hat search engine optimization. Level: 3
• C.2.12 Outline future challenges to search engines as the web continues to grow. Level: 2
• C.3.1 Define the terms: mobile computing, ubiquitous computing, peer-2-peer network, grid computing. Level: 1
• C.3.2 Compare the major features of: mobile computing ubiquitous computing peer-2-peer network grid computing. Level: 3
• C.3.3 Distinguish between interoperability and open standards. Level: 2
• C.3.4 Describe the range of hardware used by distributed networks. Level: 2
• C.3.5 Explain why distributed systems may act as a catalyst to a greater decentralization of the web. Level: 3
• C.3.6 Distinguish between lossless and lossy compression. Level: 2
• C.3.7 Evaluate the use of decompression software in the transfer of information. Level: 3
• C.4.1 Discuss how the web has supported new methods of online interaction such as social networking. Level: 3
• C.4.2 Describe how cloud computing is different from a client-server architecture. Level: 2
• C.4.3 Discuss the effects of the use of cloud computing for specified organizations. Level: 3
• C.4.4 Discuss the management of issues such as copyright and intellectual property on the web. Level: 3
• C.4.5 Describe the interrelationship between privacy, identification and authentication. Level: 2
• C.4.6 Describe the role of network architecture, protocols and standards in the future development of the web. Level: 2
• C.4.7 Explain why the web may be creating unregulated monopolies. Level: 3
• C.4.8 Discuss the effects of a decentralized and democratic web. Level: 2
• C.5.1 Describe how the web can be represented as a directed graph. Level: 2
• C.5.2 Outline the difference between the web graph and sub-graphs. Level: 2
• C.5.3 Describe the main features of the web graph such as bowtie structure, strongly connected core (SCC), diameter. Level: 2
• C.5.4 Explain the role of graph theory in determining the connectivity of the web. Level: 3
• C.5.5 Explain that search engines and web crawling use the web graph to access information. Level: 3
• C.5.6 Discuss whether power laws are appropriate to predict the development of the web. Level: 3
• C.6.1 Define the term semantic web. Level: 1
• C.6.2 Distinguish between the text-web and the multimedia-web. Level: 2
• C.6.3 Describe the aims of the semantic web. Level: 2
• C.6.4 Distinguish between an ontology and folksonomy. Level: 2
• C.6.5 Describe how folksonomies and emergent social structures are changing the web. Level: 2
• C.6.6 Explain why there needs to be a balance between expressivity and usability on the semantic web. Level: 3
• C.6.7 Evaluate methods of searching for information on the web. Level: 3
• C.6.8 Distinguish between ambient intelligence and collective intelligence. Level: 2
• C.6.9 Discuss how ambient intelligence can be used to support people. Level: 3
• C.6.10 Explain how collective intelligence can be applied to complex issues. Level: 3

Provide an answer from a number of possibilities. Recognize and state briefly a distinguishing fact or feature.

Produce a plan, simulation or model.

Assess the implications and limitations; make judgments about the ideas, works, solutions or methods in relation to selected criteria.

Arrange or order by class or category.

Give the precise meaning of a word, phrase, concept or physical quantity.

Represent by means of a labelled, accurate diagram or graph, using a pencil. A ruler (straight edge) should be used for straight lines. Diagrams should be drawn to scale. Graphs should have points correctly plotted (if appropriate) and joined in a straight line or smooth curve.

Add labels to a diagram.

Give a sequence of brief answers with no explanation.

Give a specific name, value or other brief answer without explanation or calculation.

Add brief notes to a diagram or graph.

Use an idea, equation, principle, theory or law in relation to a given problem or issue.

Obtain a numerical answer showing the relevant stages in the working.

Give a detailed account or picture of a situation, event, pattern or process.

Make clear the differences between two or more concepts or items.

Find an approximate value for an unknown quantity.

Give a brief account.

Offer for display, observation, examination or consideration.

Follow and record the action of an algorithm.

Break down in order to bring out the essential elements or structure. To identify parts and relationships, and to interpret information to reach conclusions.

Give a judgment based on a given statement or result of a calculation.

Give an account of the similarities between two (or more) items or situations, referring to both (all) of them throughout.

Give an account of the similarities and differences between two (or more) items or situations, referring to both (all) of them throughout.

Develop information in a diagrammatic or logical form.

Give an account of the differences between two (or more) items or situations, referring to both (all) of them throughout.

Reach a conclusion from the information given.

Prove or make clear by reasoning or evidence, illustrating with examples or practical application.

Manipulate a mathematical relationship to give a new equation or relationship.

Obtain the only possible answer.

Offer a considered and balanced review that includes a range of arguments, factors or hypotheses. Opinions or conclusions should be presented clearly and supported by appropriate evidence.

Consider an argument or concept in a way that uncovers the assumptions and interrelationships of the issue.

Give a detailed account including reasons or causes.

Express precisely and systematically the relevant concept(s) or argument(s).

Use knowledge and understanding to recognize trends and draw conclusions from given information.

Observe, study, or make a detailed and systematic examination, in order to establish facts and reach new conclusions.

Give valid reasons or evidence to support an answer or conclusion.

Give an expected result of an upcoming action or event.

Represent by means of a diagram or graph (labelled as appropriate). The sketch should give a general idea of the required shape or relationship, and should include relevant features.

Propose a solution, hypothesis or other possible answer.

Consider the merits or otherwise of an argument or concept. Opinions and conclusions should be presented clearly and supported with appropriate evidence and sound argument.

a group or system of interconnected people or things.