System Fundamentals

Define the terms: hardware, software, peripheral, network, human resources.

Hardware

• Physical component devices that are the building blocks of computing devices.
• Eg. CPU, RAM

Software

• Any set of machine-readable instructions which direct a computer’s processor to perform specific operations.

Peripheral

• A piece of hardware that is externally connected to a the computer system;
• such as a keyboard;

Network

• A telecommunications network that allows computers to exchange data.

Human Resources

• The set of individuals that make up the workforce of an organization.

Describe the roles that a computer can take in a networked world.

Client

• A piece of computer hardware that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the server by a network.

Server

• A computer program or device that provides functionality to other devices called “clients”.

DNS Server

• Translates human-written domain names to their corresponding machine-readable IP addresses.

Dynamic Host Configuration Protocol (DHCP) Server

• Enables computers to request IP addresses and networking parameters immediately, eliminating the need for a network administrator to configure these settings manually.

Email Server

• A software that transfers electronic mail messages from one computer to another using a client-server architecture.

Router

• A networking device that forwards data packets between computer networks.

Firewall

• A network security system that monitors network traffic based on predetermined security rules.
• Monitors traffic going into and out of the network and can block suspicious traffic.

Describe the purpose of the following hardware components of a network: (i) Router [2]

The router uses a protocol;

to determine which data packets are to be routed to certain interfaces within the network;

(ii) Network interface card (NIC)

Network interface cards are used to connect each computer to the network; so they can communicate with the network router to receive information packets;

Identify roles that a computer can perform in a network (Exam Answer):

Client;

Server;

Router;

Firewall;

Network security method (Exam Answer):

Encryption; UserID; Trusted MAC addresses;

Outline two ways in which access to sensitive data can be managed. (Exam Answer):

Access rights;

For different groups of people or computers even;

User id and password;

Only authorized users can access;

File systems should be encrypted (as it passes throughout a network / resides on computers); to make data unusable if accessed by unauthorized user;

Outline two ways to improve the security of the company’s network (Exam Answer):

Each user should have a user ID and a personal password;

Passwords should be regularly changed;

In order to prevent intruders/strangers from accessing the company's network; the router is set to accept only specific MAC addresses;

Role of a Router in a Network Exam Answer:

controls the flow of data in the network;

inspects address of data packets;

directs to the appropriate network path/ selects a path between networks (by inspecting address of data packets);

securely transmits data packets (across that path toward the intended destination);

Evaluate the use of trusted media access control (MAC) addresses as one method of network security (Exam Answer).

Each (wireless network) adapter has a unique label called a MAC address;

Routers uses these addresses to identify/authenticate computers (routers include an option to whitelist or blacklist certain devices based on MAC addresses, so access could be restricted to any device which is not in the whitelist);

One disadvantage is that the whitelist should be amended any time a new device is purchased / when access to guests should be granted;

Also this method is useless against hackers who use programs which intercept data passing through network and report the MAC address of any device communicating on the network;

Ethics

• Who/what is affected by this issue?
• What are the possible benefits for those affected?
• What are the possible harms for those affected?
• Which option(s) will produce the most good and least harm?
• If one is harmed and other benefits, how do you decide who or what matters most?

The company is considering sharing its customers’ data with marketing organizations. (d) Explain why there could be ethical issues for the company when sharing its customers’ data.

privacy of customer/ person data;

company needs to gain permission from customer;

customer would need to be able to view all data details;

customer must be informed about all uses that will be made of data;

customer must be informed to whom data will be disclosed. legal issues to do with unauthorized disclosure of customer data;

Identify the context for which a new system is planned

Purpose

• What is the primary purpose of the new system? Identifying the primary purpose of the system will help clarify the context in which it will be used.

Users:

• Understanding the needs and characteristics of the users can help determine the context in which the system will be used.

Environment:

• Understanding the environment in which the system will be used such as a business or personal setting can help determine the context.

Constraints:

• What constraints will the system operate within? Understanding the constraints that the system will face will clarify the context in which it will be used.

Requirements:

• What requirements must the system meet in order to be successful.

Identify the relevant stakeholders when planning a new system.

Customers:

• Customers are the ones who will be using the new system, their needs and preferences should be considered in planning the system.

Employees:

• Employees are important stakeholders as they will use the system on a daily basis. Their feedback can help ensure that the system is easy to use.

Management:

• A stakeholder group that is responsible for overseeing the implementation and operation of the new system. Their input is successful for the success of the new system.

Investors:

• Have financial stakes in the success of the new system. Their input can help ensure the system meets their financial expectations.

Suppliers:

• Provides goods or services to the organization that will be using the system. Their input helps ensure the system is compatible with their products or services.

Regulators:

• If the system is subject to regulatory insight, a regulator's input can help ensure the system meets all regulatory requirements.

Describe methods of obtaining requirements from stakeholders.

Surveys

• Can be used to gather information from a large number of stakeholders quickly and efficiently. They can be distributed to a large number of people and their results can be organized automatically. Surveys are cost effective. Surveys allow users to provide input while remaining anonymous which encourages honesty and accurate feedback and surveys can be completed whenever most convenient for the stakeholder.
• They may have low response rates and not provide enough detail.

Interviews

• One-on-one or small group meetings with stakeholders to gather information about their needs and expectations. Allows for in-depth discussions where the interviewer can benefit from asking follow-up questions to clarify and validate their understanding. Interviews are more personal and may build rapport with stakeholders which encourages them to voice their true opinions. Interviews can be tailored to specific stakeholder groups allowing for more focused and useful input.
• The process of interviewing is time-consuming, especially when there is a large number of people to interview, and resource intensive as it requires a facilitator to be present. Also some stakeholders may not be comfortable with an interview.

Direct Observations

• Observing stakeholders performing their daily tasks can provide valuable insights into their needs and characteristics. Direct observation provides real-time insights by allowing facilitators to see how stakeholders interact with a system, capturing contextual details and discovering unexpected requirements that may be missed in interviews or surveys. However, it can be disruptive, resource-intensive, and may not suit all stakeholders, as some may feel uncomfortable being observed. Its scope is limited to the specific tasks being observed, potentially missing broader requirements.

Outline, Exam Answer:

Surveys;

(General) questions distributed to many stakeholders as a written or online document;

Interviews;

(Specific) questions asked of nominated stakeholders in an individual setting;

Direct observations;

Observer watches stakeholders performing their current tasks;

Direct Observation (Exam Answer):

Advantages

Direct observation is systematic/structured process;

Direct observation allows the current computer system to be studied in its natural setting;

Direct observation provides a better understanding of the way a computer system is used;

Disadvantages

Direct observation is susceptible to observer bias;

Direct observation also can affect the behavior of users/process being observed;

Direct observation is time consuming;

Surveys Advantages and Disadvantages (Exam Answer):

Advantages:

Surveys allow analysts to obtain appropriate information quickly;

from a large number of persons / stakeholders;

Standardized question formats are prepared;

that can provide data that can be easily quantified/allow quantitative analysis (the success of a survey depends on the effectiveness of questions);

The use of standardized formats; minimizes the risk of the analyst adding their opinion; Survey is a straightforward/easy/practical way of gathering data;

it can be distributed using various methods (printed copies, e-mail, embedded in a website, online forms)

Surveys allow greater anonymity for respondents;

which can lead to more honest responses;

Disadvantage:
Poorly designed surveys;

May make it difficult to analyse the data;

(Response may be limited/not all questions answered / not all forms will be returned; Can be challenging to analyse the collected data ;)

Questions in the survey were not effective;

Can be differences in how people understand the survey questions; Data gathered cannot be quantified;

Describe appropriate techniques for gathering the information needed to arrive at a workable solution

Examining Current Systems

Examining Competing Products

Organizational Capabilities

• Does the company have the right people to make this solution, or to what extent can any existing systems be leveraged for the new solution.

Literature Searches

Exam Answer:

Examining current systems (using interviews/ surveys/direct observation);

To compare the existing system against possible requirements to identify missing features;

Examining competing products;

To compare own system with competitors to enable decisions on features to add;

Review of organizational capabilities;

To determine how well the organization manages resources to gain an advantage over competitors;

Literature searches;

To research current methods and to help inform development choices;

Construct suitable representations to illustrate system requirements

Use Cases

• A description of a system's behavior as it responds to a request from a user. Use cases can be used to present the functional requirements of a system.

User Stories

• A description of a feature from the perspective of a user. Can be used to present both the functional and non-functional requirements of the system.

Requirement Specification

• A detailed document that describes the requirements for a system.

Requirements Traceability Matrix

• A table that shows the relationships between requirements for a system. It can be used to track the development of a system and to ensure that the system addresses all the requirements.

Prototypes

• Simplified versions of a system that are used to test and refine requirements. They can be used to demonstrate the proposed system to clients in order to get feedback on the design and functionality of the system.

Flowcharts

• Diagrams that show the steps in a process. Represents the logic and flow of a system.

Describe the purpose of prototypes to demonstrate the proposed system to the client.

• Prototypes allow a client to see and interact with a rough version of the system, which can help them understand how the system works and visualize the final product and how it may fit into their organization. Prototypes also allow the client to provide feedback on the design and functionality of the system before the final version of the system is constructed. This also minimizes risk by allowing the client to address any concerns or problems before anything final is made.

Exam Answer:

• Advantage: Prototypes help end-users visualize the final product and offer early feedback to the design team.
• The final product meets the requirements/ is more successful; as feedback is provided by the users during the development process; Costs/time saved at a later stage; as early feedback avoids later changes (which may require a considerable amount of time/cost); The best design can be decided upon early; As it allows different prototypes can be tried out/tested;
• Not ideal when: Prototyping may be unnecessary for simple projects or where the developer is the sole user.
• Prototyping can be too costly for large/resource-intensive systems or unsafe where trial and error could be harmful (e.g. nuclear systems).

Discuss the importance of iteration during the design process

Iteration in the design process

• Cyclical process of designing, prototyping, testing and refining a solution based on feedback and analysis. This process creates effective and robust solutions.

Identifying and Correcting Flaws

• Early Detection: iteration allows for early detection of flaws in the system. Testing and gathering feedback at each stage ensures potential problems are identified before they become deeply ingrained in the system.
• Improved Efficiency: Correcting early, smaller problems is much more efficient than trying to fix them later in development.

Incorporating Feedback

• User-Centered Design: Iteration facilitates user-centered design by incorporating stakeholder feedback at each stage of development also making sure the system meets the actual needs of users.
• Enhanced Usability: Feedback from users also improves the usability and accessibility of systems. Iterative user testing reveals areas of difficulty leading to a more intuitive user experience.

Adapting to Change

• Flexibility: Iteration allows for flexibility in the design process, accommodating changes in requirements or technology.
• Responsiveness: The iterative process enables developers to respond to unforeseen issues and adapt their design.

Refining and Improving Solutions

• Optimization: Iteration allows for continued refinement and optimization of the system.
• Innovation: The iterative process encourages experimentation and exploration leading to more innovative solutions.

Exam Answer:

Testing is important (at every stage) to make sure the system operates in line with user requirements/as intended;

Another cycle of analysis and design might be needed because the stakeholder could ask for modifications;

because errors or omissions are found that need to be corrected;

To prevent the end user being dissatisfied with the final system;

to reduce time delay/ using more resources / avoid higher cost;

new/different features could be added that affect the current design;

which affects the costs/ delivery time / hardware requirements/ contributes significantly to system quality and performance;

Why should a product be thoroughly tested before deployment (Exam Answer):

so that it functions the way it is supposed to;

so that it meets its design specifications functions;

to eliminate any errors/bugs;

so that the speed/capacity/compatibility issues are solved;

so that all security features are configured and enabled;

because wrong/incorrect/stolen information could have serious consequences for its customers (accept an actual consequence);

because wrong information could harm the company’s reputation / loss of earnings / sued/ etc;

Describe the need for change management.

Change Management

• Identifying, documenting and approving or rejecting changes to a system in production.

1. Helps prevent unintended consequences of changes to a system. Carefully reviewing changes reduces the risk of new errors being introduced.
2. Helps maintain the integrity of the system. Through controlling the introduction of changes, the system is kept in a stable state, crucial for maintaining the reliability of its performance.
3. Helps ensure that changes are properly documented and communicated to all relevant parties. This ensures everyone is aware of the changes and how they might affect the system.
4. Helps facilitate the efficient implementation of changes to the system. Through following a structured process of reviewing upcoming changes, the implementation of the change is streamlined.

Things to Consider within Change Management (Exam Answer):

Context - An international organization is moving its offices from Africa to Europe. All of its data will need to be moved to a new system.

Issues with personnel;

such as redundancy/retraining/employee not willing to move to Europe, etc.;

Changeover decisions;

such as direct changeover/ parallel running etc;

Time needed;

for merging/aligning the two systems;

Costs involved;

in the aligning of the two systems/ in the changeover period of time/ for buying new software or hardware/ cost for additional working hours/ cost of additional staff;

Testing;

Of the new systems with the new data;

Data entry;

If migration not possible/ cost and time involved;

Compatibility issues that may arise from an international business merger (Exam Answer):

Data representation differences / different data structures (e.g., date format, incompatible file formats);

Incompatible hardware;

Incompatible operating systems / different software versions;

Outline compatibility issues resulting from situations including legacy systems or business mergers.

1. Incompatibility of hardware and software: The new system may use hardware or software that is not compatible with the legacy system.
2. Incompatibility of data formats: the new system may uses data formats that are not compatible with the existing system, in such case it may be necessary to convert the data to enable compatibility.
3. Incompatibility of protocols: The new system may use protocols that are incompatible with the existing system, in such case protocol conversion may be necessary to enable compatibility.
4. Incompatibility of processes: The new system may use processes that are incompatible with the existing system, in such cases modifying the processes may be necessary to enable compatibility.
5. Incompatibility of user interfaces: If the new system has a user interface significantly different from the existing system, it may be difficult for users to adapt to the new system, this may create the need for user training or other support so that users can use the new system effectively.

Problems w Maintaining a Legacy System (Exam Answer):

Applications in the legacy/outdated system do not have upgrades;

Documentation of the legacy system might be missing/incomplete/unreliable;

Data cannot be converted to newer formats;

Legacy systems are typically large and complex systems/ mainframes, so programs might be disorganized/hard to understand/expensive to change;

It may be difficult to find system engineers/ employees/ programmers familiar with the old programming languages/ old operating systems to maintain the system;

Suggest various types of testing.

Acceptance Testing

• Performed by customers or relevant stakeholders to validate whether the system is ready for deployment.

Beta Testing

• Form of UAT, a beta version of the system is released to a limited audience outside the programming team for a fresh pair of eyes to assess the system's functionality.

Why is used Exam Answer:

Testers outside the organization use the operating system in a “real world” setting; Enables feedback to be given to the developers;

So that the software can be improved/corrected/debugged;

Before it is finally released;

“Real world” testers may find more bugs as the system is used in ways not originally intended / tested;

Debugging

• Process of finding and resolving defects that prevent efficient operation of the system. Is harder with interdependent systems as fixing bugs may create new ones.

Evaluate alternative installation processes

Parallel 

• When the new system is used while the old system is also still in use

Advantages

• Users can compare the output of the old system with the output of the new system to ensure correctness.
• Small risk of data loss because the known-good system is still in use.

Disadvantages

• Increases time as data must be entered in two different systems
• Intensive data entry can result in slight discrepancies.

Use case: a hospital replacing a heart rate monitor for a patient

Why Parallel Running Is an Expensive Changeover Method (Exam Answer):

Two systems will be run simultaneously so that operations are not disrupted, this is a costly operation;

Because both systems and all their resources need to be maintained/run at the same time;

Data migration has many risks/is a complex process so the costs to implement it correctly are high because of additional costs due to delays /lost time/data entry;

The decision on when and whether the new system is ready to remove the old one depends on the testing and validation of the new system, which includes some additional costs associated with the testing/validation of the system;

Other suitable answer*

Phased

• Small parts of the new system gradually replace the old system.

Advantages

• User training can be completed in small parts.
• A failure in the new system has minimal impact because it is only a small part of the entire system
• Issues around scale can be addressed without major impact.

Disadvantages

• Takes more time to get the full new system
• Possibility of data loss if a part of the new system fails.

Pilot

• When a small group of people use the new system before it is released to the wider public

Advantages

• Training of the system can be supported by the pilot group who should already have experience with the system.
• Problems can be found and addressed without impact on the entire organisation.

Disadvantages

• Issues of scale may arise. The system may work for the smaller pilot group but not for the entire organisation.

Direct

• The new system is implemented without any pilot or phased implementation.

Advantages

• If the system is not critical, this is a good implementation strategy.

Disadvantages

• If the system is not guaranteed to be fail-proof, this is not a good implementation strategy.

Exam Answer:

Compare Direct with Parallel Implementation (Exam Answer):

there is no extra cost;                                                                                 for running two systems/for extra salaries (no need to increase the number of employees);

benefits can be gained immediately;                                                         because new system is better than the old;

if there is a bug in the new system;                                                                 there is not a second system to fall back on/could be disastrous for the company;

employees will need to be capable of using the new system immediately;                 without training/with training in advance but not on the system;

Discuss problems that may arise as a part of data migration.

Data Migration

• Moving data from one system to another is called transferring the data. When you permanently move data from one system to another, you are migrating the data.

Issues That May Arise During Data Migration

1. Data Loss: There is a risk of data loss during migration due to several reasons such as network issues, hardware failures or data corruption
2. Compatibility Issues: The source and destination system may use different data formats which may create data compatibility issues.
3. Data Integrity: Data integrity issues may arise when the migrated data is not consistent with the original data.
4. Performance Issues: The migrated data may not be optimized for the destination system.
5. Security Risks: There is a risk of unauthorized access of the data during migration.
6. Dependencies: There may be dependencies between the data elements that are not taken into account during migration.
7. Complexity: Migrating large amounts of data may be complex and require additional resources.

Exam Answer

Different languages used;

Which leads to translation/communication issues;

Different character sets used;

Which could lead to inconsistent/incorrect results;

Incompatible file formats;

Which could lead to incomplete or incorrect data transfer / data loss;

Different file structures / different employee records;

Which will result in a mismatch of data/ incorrect data;

Compare the implementation of systems using a client’s hardware with hosting systems remotely

Implementation Using Clients Hardware:

• Installing on client premises

• Provides the client direct control over the system and the ability to customize it to their specific needs.

• It requires the client to have the necessary hardware in place to support the system.
• The client is responsible for maintaining the system.

Hosting System Remotely

• Provides access to the system through the internet.
• Eliminates the need for clients to have their own hardware
• Most cost and time effective
• Clients have less control over the system and limited ability to customize it.

Describe the importance of user documentation.

Important because it teaches users:

1. How to use the software.
2. The features of the software
3. The tips and tricks of the software
4. How to resolve common issues.

Markscheme:

• User efficiency – so users can operate the system correctly.
• Support/Troubleshoot – assists users when errors occur.
• Accuracy – ensures correct method use for reliable results.
• Improved user experience – users can make full use of system features.

State the importance of Technical (NOT USER) Documentation Exam Answer:

Technical documentation explains how to install software;

Technical documentation describes the hardware configuration/operating system needed (to install this software);

Evaluate different methods of providing user documentation.

Evaluate different methods of delivering user training.

Identify a range of causes of data loss.

Malicious Activity - deliberate or accidental sabotage by a person.

Natural disaster - Destroyed systems through floods, storms and other natural disasters.

System Failure - Hardware or software malfunctions

Exam Answer:

Malicious activities;

An unauthorized user gaining access to data and deleting/altering it;

Natural disasters / earthquake / storm / power loss;

Causing the system to crash and destroy data;

Malware/viruses/spyware/worms;

Which infiltrate and damage the data;

Human error;

Accidental deletion/overwriting of files;

How can corrupted data be recovered (Exam Answer):

Restore files from a backed-up data file;

ensuring it is a recent copy to minimize loss;

a parallel/failover system could be operated;

that could be switched to (if the live system is corrupt);

data recovery software could be (installed and) run;

to repair corrupted files;

Describe one way offsite storage can be used to prevent data loss (Exam Answer).

copies of all important data files (backup) could be placed on two separate hardware devices;

which are placed in two different physical locations;

a remote file server could be set up;

for uploading all important data files;

internet backup service could automatically back up (all important) data files;

to a remote server that could be accessed/controlled over the internet;

Outline the consequences of data loss in a specified situation.

Valuable Data Lost

• Data loss may result in some valuable data being lost such as for hospitals regarding patient medical records or perhaps in a research project where the data is lost.

Financial Loss

• Data loss may result in business not being able to complete transactions or access financial data resulting in the loss of finances.         

Confidential Data

• Data loss may compromise sensitive information.

Describe a range of methods that can be used to prevent data loss.

Back-Ups

• Back ups can be used to restore data. Repeatedly backing up data helps reduce the risk of large data loss.

Redundancy

• Redundant systems and storage ensures that there is always a copy of data available.

Replicating Data

• Replicating data and storing it in an offsite location helps prevent data loss from hardware failures or natural disasters.

Data-Encryption

• Encrypting data prevents unauthorized access to the data.

Data-Governance

• Data governance policies and procedures help ensure that data is stored responsibly, reducing the risk of data loss.

User-Training

• Training users on the best practices to handle data prevents data loss from user-error.

Data Loss Prevention Software

• DLP software monitors and controls the flow of data within an organization helping prevent data loss from accidental or intentional leaks.

Exam Answer:

Copies of backup could be kept off-site/cloud backup;

Unlikely that the other site would be affected by the natural disaster/can be reloaded/reinstalled if needed;

Incremental backup only backs up data that has changed;

Therefore, requiring less storage capacity / can be completed more quickly than a complete backup;

Failover system/mirrored system/disk mirroring;

A duplicate copy to be used in the event the main system fails;

Describe strategies for managing releases and updates.

Manual Updates

• Downloaded and installed by the end user.
• The user is notified about an update and must decide if they want to download and update.

Automatic Update

• Downloaded and installed without needing the user to intervene.
• The application polls to check for an update and downloads and installs it when there is one.

Manual Strategies:

1. Phased Release – Gradual rollout of updates to specific user groups to monitor performance and catch issues before a full deployment.
2. User Surveys & Feedback – Directly collecting user feedback through surveys, interviews, or forums to evaluate the effectiveness of updates.
3. Feature Toggles (Feature Flags) – a technique that allows dynamic activation or deactivation of features in real time without requiring new code.

Automatic Strategies:

1. Incremental Deployment – Small, frequent updates are automatically deployed to reduce risk and ensure continuous improvements.
2. Rolling Release – A continuous update model where new features or fixes are deployed as soon as they are ready, eliminating traditional versioned releases.
3. Feature Toggles (Feature Flags) – Often automated, allowing dynamic activation or deactivation of features in real time without requiring new code.
4. A/B Testing (Split Testing) – A method where different user groups receive different versions of a feature to analyze which performs better, often automated.
5. Scheduled Maintenance Windows – A designated time period when system updates are deployed, usually automated to minimize downtime.
6. Backward Compatibility – Ensuring new updates do not break existing functionality by using automated versioning and testing techniques.

The ways users can be notified about software updates (Exam Answer):

A message can be sent to the user (When the software is installed and registered, the user provides an email address / phone number);

With a link to the update;

notifications/alerts are sent to the computer (a cookie is placed on the user's computer which communicates with the software developer);

about automatic updates;

(when the program is run) it queries a URL the program developer has built in to check whether the current version matches the latest version;

if not, notifications/alerts are sent;

Define the term usability.

Usability

• The degree to which a software can be used by specified users to achieve quantified objectives with effectiveness, efficiency and satisfaction in a quantified context of use.

Identify two usability factors that need to be considered in the design of a website (exam answer).

complexity / simplicity / amount of effort to get a result / number of errors with the time taken to move past them;

readability / comprehensibility / reading or writing speed;

learnability / time to accomplish tasks on the first use;

effectiveness ( user performance);

efficiency (time needed to complete a task);

Identify a range of usability problems with commonly used digital devices

Mobile Phones

• Small Screen Size: Harder to read text, view images or use touch based controls.
• Touch Screen Sensitivity: Miss taps lead to unintended consequences.

Laptops

• Trackpad Usability: difficult to use the cursor precisely.
• Overheating during prolonged use: Device becomes uncomfortable and throttles performance.

Tablets

• Heavyweight for prolonged hand held use: Users experience physical strain when using the device
• Limited multifunctioning capability: Reduces productivity for users needing multiple open applications.

Smartwatches

• Small input area: difficult to type and navigate menus
• Short battery life: frequent need to charge reduces convenience.

Gaming Device

• Complex controller layout: Difficult to for users to learn how to use the controller effectively
• Online connection issues: players experience network issues more frequently.

Outline one reason why visual displays on a computer screen can create difficulties for some people (exam answer).

Visual display design is not logical;

workflows are not simple, and do not require as few interactions as possible to complete;

Visual display design is not consistent;

navigation, header, footer, and main content are not always in the same places;

Visual display design is not usable as possible;

tools are not easy to use, processes are not broken down into logical steps;

People with poor eye-sight/color blind can have difficulties to distinguish;

because of the way graphics, words and directions are used / combinations of some colours (eg, red and green);

Describe two issues resulting from the website being viewed on various devices, such as desktops and smartphones.

Most mobile displays currently have screens with fewer pixels than desktop displays and are physically smaller; typing on small on-screen keyboards is difficult; less precision (clicking a 12-pixel-high text link with a mouse is no problem but tapping the same link with fingers could be difficult); there is no mouse pointer so there is no concept of "hovering" over a page element/ remaining in an uncertain state; most modern touch screens allow zooming; allow the user to perform gestures using one or more fingers, such as swiping/pinching;

Identify methods that can be used to improve the accessibility of a system.

MacOs

• Voice Over: provides spoken descriptions of on screen elements, useful for the visually impaired.
• Zoom: allows users to magnify their screen, for the visually impaired.
• Dictation: allows users to input text using their voice: useful for people with mobility issues.
• Siri: provides voice activated control and assistance.
• Switch control: allows people with physical disabilities to control the computer using adaptive keyboards and mouses.

Windows

• Speech recognition: allows users to control the computer with voice commands.
• Sticky Keys: Allows users to execute keyboard shortcuts while pressing one key at a time for people that struggle with holding multiple keys at once.
• Access Center: Users can find various features and settings for disabilities providing customizable accessibility features.

Touch screens; Voice recognition; Text-to-speech; Braille keyboard A colour-blind option Large font option

Discuss the moral, ethical, social, economic and environmental implications of the interaction between humans and machines

Key Ideas

• Social - relating to society or its organization.
• Economic - pertaining to the production, distribution, and use of income, wealth, and commodities
• Environmental - relating to the natural world and the impact of human activity on its condition

Who/what is affected by this issue?

What are the possible benefits for those affected?

What are the possible harms for those affected?

Which option(s) will produce the most good and least harm?

If one is harmed and other benefits, how do you decide who or what matters most

Computer Organization

Central Processing Unit (CPU)

• The electronic circuitry that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output operations.

Why a single processor may not be able render 3d graphics effectively:

• Single processor is mainly occupied with the OS jobs / might not be able to handle multiple jobs/;
• Rendering 3D graphics requires a great deal of processing (which a single processor may not be able to give);
• If attempting rendering on a single processor, a (very) high clock speed is required; which may not be available;
• 3D graphics processing is (inherently) parallel;

A single processor is not able to handle parallel processing

Arithmetic Logic Unit (ALU)

• Data is loaded into the ALU from an input register (small amount of storage within a CPU). The ALU performs arithmetic and logical operations on the data and stores the result in an output register.
• The control unit (CU) moves the data between memory, registers and the ALU.
• Control Unit (CU) coordinates the movement of data between the components of the CPU and manages the flow of control within the CPU.

Control Unit

• The control unit obtains data from memory
• decodes the instructions into commands
• Controls the transfer of instructions and data in the CPU
• Coordinates the parts of the CPU

Registers

• A register is a quickly accessible location within a CPU and consists of a small amount of very fast storage. It stores instructions which await to be decoded or executed. Data is loaded into registers from primary memory.

• Program Counter (PC): Stores the address of the next instruction.

• Memory Address Register (MAR): stores the address of the current instruction being decoded and executed.
• Memory Data Register (MDR): Stores the data that has been fetched from or is to be sent to, primary memory (input / output).
• Current Instruction Register (CIR): Stores the current instruction being decoded or executed.
• Accumulator (ACC): Stores the result of operations.

Purpose of the MAR (Exam Answer):

The MAR holds the memory location of data/instructions;

…that need to be accessed (read/write) (fetch/store);

It is a register inside the CPU (central processing unit) that holds the address of a memory location where data needs to be:

• Fetched (read from memory into CPU), or
  
• Stored (written to memory from CPU).

Another version:

MAR (is a register in the CPU that) stores the address of the (next) instruction/data; to be read from/written to RAM;

Purpose of MDR in Machine Instruction Cycle:

Holds (a copy of) the contents of the memory

That is to be transferred between memory and other CPU parts;

The MDR allows the CPU to work at its own speed without being affected by the difference in speed of memory operations.

Primary Memory

• Random Access Memory (RAM)

• RAM is where instructions and data are stored at runtime
• RAM can be accessed a lot faster than secondary storage,
• All data and instructions in RAM are lost when the power is turned off (volatile)
• RAM allows storage and random access to instructions and data
• Each i`nstruction and data has a unique address in RAM.
• Size is limited
• Instructions can be read from and written to it.

• Read Only Memory

• Non-volatile, is used to store programs permanently Eg. start-up or " boot " instructions.

• Can not be written to easily or at all (usually written once and not touched again)

Characteristics

Cache Memory

• Cache memory is used to reduce the average memory access time. This is done by storing the data that is frequently accessed in cache memory which allows the CPU to access the data faster because cache memory can be accessed faster than RAM.

• Cache memory can be accessed and read faster than RAM.
• Used to hold expected and frequently used data.
• Closer to the CPU than RAM (Locality)

Exam Answer:

• Cache stores frequently used program instructions close to the CPU for fast access.
• Accessing the cache is faster than accessing RAM.
• A larger cache allows more instructions/data to be stored, speeding up program execution.

Cache memory is a small-sized type of volatile computer memory;

that provides high-speed data access to a processor;

and stores frequently used computer programs, applications and data;

Thus, when a processor requests data that already has an instance in the cache memory;

it does not need to go to the main memory or the hard disk to fetch the data;

Machine Instruction Cycle

• Describes the order that instructions are processed in a computer.

1. Fetch the Instruction: The next instruction is fetched from the MAR  and stored in the instruction register (IR).
2. Decode the Instruction: The control unit (CU) decodes the instruction.
3. Execute: The control unit (CU) sends the decoded instruction to the ALU through a series of control signals.
4. Store: The result of the operations is stored in an appropriate storage location.

Explain the roles of the data and address bus in the MIC (Exam Answer):

data bus and address bus enable a processor to communicate with the primary memory; When the computer processor needs to fetch an instruction from the memory it uses the address bus to specify the (physical) address (of the memory block it needs to access);

It will get the data from (the specific) memory (block) (after checking the address bus to get the read address);

And then it will place this data on to the data bus/data bus carries the data;

When the processor wants to store results of execution to the memory it will set the write address on the address bus;

And put the data/results/to be written to memory on to the data bus (to carry this data);

Persistent Storage

• Non- volatile storage that is needed when;

• The system is turned off
• Another process requires volatile memory.
• There is a need to store data during and after running a program.

The purpose of persistent storage (Exam Answer):

To store programs / files / data in a non-volatile device so it isn’t lost;

Stores more data as it has a larger capacity;

Difference between primary and secondary memory (Exam Answer):

Primary storage is accessed by a computer's central processing unit (CPU) and secondary storage is not accessed directly by the CPU; Primary storage has lower access time / has smaller capacity/ more expensive type of memory than secondary storage (which is slower than primary storage, with larger capacity but it is cheaper); Primary storage is volatile (uses random-access memory (RAM), cache memory, or some other specialized hardware to store data while the computer is powered on/ volatile devices), whilst secondary storage on a computer is provided by non-volatile devices (such as SSD or HDD); Primary storage holds data temporarily whilst data is kept permanently/ for a long time in secondary storage; Primary storage holds currently running programs/data/operating system, secondary storage does not;

Operating System (OS)

• The OS is the most crucial software in running the computer. The OS manages the entire computer’s resources and provides common services. The OS has several key responsibilities:
• Memory Management:

• Allocation: The OS divides and allocates memory to various processes accordingly to ensure each process has sufficient memory to function properly.
• Protection: The OS ensures that one process is unable to access another's memory space without proper authorization in order to prevent data corruption and system crashes.
• Virtual Memory: The OS is able to extend available memory by creating virtual memory on a portion of the hard disk. Virtual memory is able to function like primary memory allowing the computer to run larger applications even when physical memory is limited.
• Paging & Swapping: The OS can move data between RAM and secondary storage to optimize available memory. Paging refers to the transfer of fixed-sized memory blocks while swapping refers to the transfer of entire processes.

Explain the importance of Memory Management in the Function of OSs (Exam Answer):

• The operating system allocates and deallocates memory by assigning memory blocks to programs as needed and freeing them when they are no longer in use.
  
• It ensures each program has sufficient memory to run, and if necessary, uses virtual memory to extend available memory beyond physical RAM.
  
• Memory management helps to:
  

• Prevent conflicts between programs (e.g., data overwriting),
  
• Optimize system performance, and
  
• Maximize efficient use of memory resources.

Describe how an operating system uses paging when running a program Exam Answer.

memory management method that uses secondary memory to increase the amount of primary memory;

transfers data blocks of the same size (“pages”);

from secondary storage to main storage when they are required;

and returns them to secondary storage when they are not;

• Peripheral Management:

• Device Drivers: Device Drivers enable communication between the OS and peripheral devices. The OS uses device drivers to translate their instructions to a language the specific device is able to understand.
• Input/Output Scheduling: The OS schedules and prioritizes I/O operations for devices to ensure efficient data transfer and avoid conflict between the devices.
• Buffers & Caches: The OS uses buffers and caches to temporarily store data in memory during I/O operations to allow faster data transfers and minimize impact on performance.

Explain how an operating system manages peripherals. (Exam Answer):

The operating system (OS) manages all peripheral devices by keeping track of them through an input/output (I/O) controller. It decides which process gets access to a device, for how long, and allocates or deallocates the device accordingly. Communication between the OS and the hardware is handled using device drivers and the basic input/output system (BIOS). Every peripheral device requires a specific driver that translates high-level OS instructions into low-level commands or signals the hardware can understand. These drivers may be built into the OS or installed separately when new hardware is added. Without the appropriate driver, the OS cannot communicate with the device. Device drivers are essential for peripherals such as keyboards, mice, printers, disk drives, and graphics cards. They operate in kernel space—the core part of the OS that interacts directly with hardware—and implement low-level functions like open, close, read, and write. Programs running in user space make system calls to these driver functions, enabling communication between software applications and physical devices.

Example answer:

An OS manages peripherals via their respective drivers;

For example, sound card drivers; are necessary so the OS knows exactly how to translate the 1s and 0s (that comprise the MP3 file) into audio signals;

that the sound card can output to headphones / speakers;

Explain how the operating system ensures that each customer’s data is secure when multiple users are accessing the data at the same time.

OS (memory management function) allocates / deallocates memory to each process/customer task, and guarantee each customer task the resources it needs to run correctly;

moves processes back and forth between main memory and secondary memory during execution to prevent overwriting / accidental interchange;

OS (hardware memory protection- part of an OS) isolates/protects customer’s data/applications;

and control access rights to the specified memory area (for example, prevents write access to the memory which is not allocated to the process/ customer task); and protects data / applications when in memory / RAM from malicious code (prevents attempts to execute the contents of the partition/ allocated memory);

• Hardware Interface Management:

• Processor Management: The OS allocates CPU time to various processes to ensure they each receive an appropriate amount of computing resources. It also handles process scheduling, prioritization, and context switching
• Interrupt Handling: The OS manages hardware interrupts, which are signals made by hardware devices to notify the OS of an event that needs immediate attention. The OS processes the interrupt and takes appropriate action.
• Power Management: The OS optimizes the use of hardware resources to minimize power consumption. The OS does so through techniques such as managing sleep states, turning off unused processes and adjusting CPU frequency.

Explain the role of the operating system (OS) in terms of managing the hardware resources (Exam Answer).

OS controls all the activities of computer system and acts as an interface between user and hardware;

Thus the role of OS is to keep track of who is using which resource;

to grant resource requests;

to mediate conflicting requests from different users/programs;

to allocate time to different programs or different users/ each one gets their turn to use that resource (for example printer);

to allocate space for different users, each one gets a part of the resource (for example sharing main memory/ hard disk);

Full Marks Answer:

The operating system manages hardware resources by keeping track of which programs are using which resources at any time;

It allocates CPU time to different programs, ensuring that each gets its turn (e.g., through scheduling);

It mediates conflicting resource requests, deciding which program can access a device when multiple programs request it;

It allocates memory and storage space, allowing multiple programs or users to share these resources effectively without interference.

Virtual Memory Advantages and Disadvantages (Exam Answer):

Allows more applications to run than there is available physical memory;

By the use of page/swap files/part of hard disk as primary memory;

Larger application can run;

With less real RAM;

Applications run more slowly;

Uses hard drive memory as primary memory / takes more time to switch between applications;

When a computer's virtual memory resources are overused /Reduced amount of hard drive space available for your use;

programs lock-up/do not run/disk thrashing;

Distinguish between the use of time slicing and priorities in the scheduling of processes by an operating system. (Exam Answer):

Prioritizing enables execution of the (highest priority) process until a higher priority task enters;

The OS/scheduler put processes (jobs) in the right place in a queue in order of priority (accept examples, an I/O operation has higher priority than calculations because it uses less CPU time);

Time slicing allows process to execute for a fixed time;

After each time slice, the scheduler is triggered to decide which process should run next, ensuring that all processes get a fair share of CPU time and that no single process monopolizes the processor.

Outline the function of the OS in managing primary memory (Exam Answer):

OS ensures the availability of adequate memory for data structures/objects of each running program at all times;

By allocating the memory portions to programs after freeing the space (of the computer memory);

OS (memory management unit) uses virtual memory which provides secondary memory (external storage) for program that does not have enough space in RAM for execution;

After execution of the program this memory is reallocated (used by other programs)/freed;

Identify two reasons why patches may be necessary for an operating system. (Exam Answer):

Allows bugs/error in operating system to be repaired; Allows new features to be added to operating system (such as security updates, improving functionality, improving usability, etc.); Allows compatibility issues to be improved;

Identify two methods that can be used to obtain these patches (Exam Answer).

Automatic patches/updates sent (via internet);

User requested updates (via internet);

Patches sent on CD/DVD/memory stick;

General Application software

• An application is a software that allows you to perform a specific task.

Word Processor

• An application for storing, manipulating and formatting text entered by a keyboard and providing a printout.

Spreadsheet

• An application in which data is stored in rows and columns of a grid and can be manipulated and used in calculations.

Web Browser

• An application for retrieving, presenting and traversing information resources on the world wide web.

Common Features of Applications

• Toolbars
• Menus
• Dialogue Boxes

Features of a GUI

Menus; Dialogue boxes; Windows; Icons; Pointers; Buttons;

Binary

• Base-2 number system that assigns numerical values to two different symbols, 0 (zero) and 1 (one).
• Important Definitions:

• Bit: One binary digit.
• Byte: A unit of information made up of 8 adjacent bits.
• Binary: Base 2 number system.
• Denary/Decimal: Base 10 number system.
• Hexadecimal: Base 16 number system.

Data Representation

• Computers use binary to store data.
• A binary digit or bit is the smallest unit of data in computing and can only take the form of a 0 or 1.
• A computer's processor contains billions of transistors which are tiny switches activated from electronic signals.
• The binary values 0 and 1 represent the on and off state of a transistor.
• A computer program is a set of instructions that are represented by binary digits.  
• A computer is only able to read code in the form of binary. Before any human written code can be executed by a computer processor it must be translated into binary.
• Generally all information processed by a computer like music or documents is represented by binary.

Integers

• Represented by binary.

Characters

• Represented by binary.

Strings

• A concatenation of characters represented by bits.

Colors

• Represented by the hexadecimal number system.

Exam Answer:

• Colours on a screen are represented using 24-bit colour (8 bits per red, green, and blue component).

State why hexadecimal numbers are frequently used in computing (Exam Answer):

Hexadecimal numbers are used for shorter representation of data because a (modern) byte can be represented exactly by two hexadecimal digits; Hexadecimal numbers are used for shorter representation of data, because computers store and handle binary digits, and four binary digits make one hexadecimal digit;

State the number of bits used to represent a non-primary colour, such as yellow

24;

State the maximum number of colours that can be represented in a computer pixel.

256 x 256 x 256

Image

• A matrix of pixel values.

SOUND

3. Analog-to-Digital Conversion (ADC)

This is the critical moment when it becomes “computer-readable.”

Two key steps here:

• Sampling: The sound wave is measured at regular time intervals (e.g., 44,100 times per second in CDs — called 44.1 kHz sampling rate).
  
• Quantization: Each sample is rounded to the nearest value that can be represented with a fixed number of bits (e.g., 16-bit audio can represent 65,536 different levels).
  

📊 Result: A list of numbers!

Each number represents the amplitude (volume level) of the sound at a specific moment in time.

💾 How It’s Stored

These samples get saved in digital audio formats like:

• WAV (raw, uncompressed)
  
• MP3 (compressed — some data removed to reduce file size)
  
• FLAC (compressed, but lossless)

Decimal to Binary

Binary to Decimal

Binary to Hexadecimal

AND Truth Table (Needs to be both 1 to be 1)

OR Truth Table (only one 1 is needed for 1)

NOT Truth Table

NAND Truth Table (Only two 1 makes 0)(Opposite of AND)

NOR Truth Table (Only two 0 makes 1)(Opposite of 1)

XOR Truth Table (if values are same output 0 otherwise output is 1)

Networks

Computer Network

A group of computers and other computing hardware devices that are linked together through communication channels/cables/wirelessly;

To enable communication (sharing files, sharing information) between systems/among a wide range of users;

Local Area Network (LAN)

• A computer network that interconnects computers within a limited area Eg. residence, school, etc.

Wide Area Network (WAN)

• A computer network that extends over a large geographical area. Eg. businesses, governments, etc

Virtual Local Area Network (VLAN)

• A network that groups together subsets of computers using the same LAN and isolating their traffic.

Storage Area Network (SAN)

• Provides access to consolidated block level data storage.

Wireless Local Area Network (WLAN)

• A wireless distribution method for devices using high frequency radio waves and an access point to the internet to allow users to move around a coverage area while maintaining a network connection.

Internet

• A global system of interconnected computer networks that use the internet protocol suite to link devices worldwide. A network of networks co nsisting of a broad range of networks from local to global scope linked by electronic, wireless and optical networking technologies.

Intranet

• An intranet is a private network accessible only to an organization’s staff. It is used to securely share company information, resources, and communication within the organization

Extranet

• An extranet is an extended form of an intranet that allows controlled access to external users, such as business partners, suppliers, or customers. It bridges the internal network (intranet) with selected external parties

Virtual Private Network (VPN)

• A VPN extends a private network over a public network enabling users to send and receive data across public networks as if their computers were directly connected to a private network.

Personal Area Network (PAN)

• Used for data transmissions across personal devices.
• Features of PAN
• Smallest type of network; Consists of connected devices in close proximity to the individual using them; Connected via Bluetooth/wireless; Suitable example: smartphone to car connection;

Peer to Peer (P2P)

• P2P computing is a distributed application architecture that equally divides tasks peers.

Differences between WAN and LAN (Exam Answer):

• WAN spans national/international areas; LAN covers a smaller (local) area.
• WAN may use public networks; LAN often uses private infrastructure.
• LAN is more secure; WAN is less due to public transmission.
• LANs have higher bandwidth and faster speeds.
• LANs are cheaper and simpler to maintain.
• WANs involve more devices and need hardware to link networks.

Network Standards For Constructing Networks

• Interoperability Standards: Ensures different devices and systems can work together efficiently regardless of their manufacturer.
• Compatibility Standards: Ensures new devices and systems can be added to an existing network without problems.
• Safety Standards: Ensures the safety of the network user by establishing reliable guidelines for the design and operation of network components.
• Performance Standards: Optimizes the performance of networks by specifying how they should transmit and receive data.
• Cost Effectiveness: Adopting standards helps reduce costs by allowing companies to use existing reliable network components rather than creating custom solutions for the different aspects of a network.

Breaking Down Communication

• Communication between devices occurs by passing data down through the layers on the sender’s side and up through the layers on the receiver’s side
• Sender Side: Starts at the application layer where data is generated. Data passes through each layer being encapsulated and addressed with headers and control information. Finally at the physical layer the data is transmitted over the physical medium through signals
• Receivers Side: Data arrives at the physical layer and moves up through each layer. Passing through the layers the data is processed accordingly and finally reaches the application layer in human readable format.

Outline the concept of the Open Systems Interconnection (OSI) model in communication across a network (Exam Answer)

The OSI is a standardized model for network connection;

Consists of (7) layers;

Each dealing with specific parts of network communication;

For example, the physical layer which defines the physical connection;

OSI Model

• Application Layer 7
• Presentation Layer 6
• Session Layer 5
• Transport Layer 4
• Network Layer 3
• Data Link Layer 2
• Physical Layer 1

Packet

• A basic unit of communication over a digital network.
• When data is transmitted it is first broken down into data packets before it is reassembled at its destination.

Reasons for which the Speed of Data Transmission Over a Network may Vary

• Type of connection (week, strong)
• Network traffic (may fluctuate throughout the day)
• Distance
• Internet Service Provider
• Cable Quality

Exam Answer:

The speed of data transmission (on a wireless network) slows down;

The further the receiver is from the transmitter;

 Passing through obstructions such as solid walls;

Can slow down transmissions (on a wireless network);

The bandwidth available for transmission on a wireless network is finite;

So, transmission speeds can be affected if the number of users on the network increases;

Outline two reasons why there might be a reduction in data transmission speed at certain times (exam answer).

malicious software/spyware/malware / viruses; attacking the system;

the type of connection;

valid outline for the slow down (depending on the type of connection);

Note: There are many types of internet connection: wireless connections, wireless hotspots, mobile internet, broadband connections, fixed wireless and satellite connection, cable, DSL;

hardware malfunction;

internet speed can considerably slow down if modem-router configuration is not correct / updated;

external factors;

during the peak hours of daytime the most visited websites encounter more network traffic than what has been anticipated;

Advantages of Wireless Networks

• Convenience: Maintain a network connection from any location within the network coverage area. Not limited to a cable restraining users to one location.
• Easy Setup: Removes the need for cable making set up easier and more cost effective.
• Expandable: When wired networks may need additional cabling, wireless networks can be expanded easier with existing equipment.

Disadvantages

• Performance: The performance of wireless networks are generally worse than wired networks. Data transmissions and network connection is usually slower.
• Distance: As users move further away from the access point their connection becomes weaker.
• Can be Obstructed: A wireless connection can be obstructed by everyday items such as walls, furniture, etc.
• Security: Wireless networks are generally less secure than wired networks.
• Backup Plan: Wireless networks generally don't have good back up protocols when connection fails.

• (b) Wired vs. wireless reliability:

• Wireless depends on signal strength, distance from the router, and environment.
• Slower data transfer and more interference risk.
• Wired is more stable and less affected by physical surroundings.
• wired network is only accessible with a physical cable connection and in wireless networks signals are broadcasted outside of the building; leaving it open to the public and potential hackers/ it is easy to intercept transmissions;

Hardware Components

• Wireless Access Point: A wireless access point acts as a bridge between the wired network and the wireless devices providing them with a network connection.
• Wireless Router: A wireless router acts as the combination of a wired router and wireless access point. It routes network traffic between local and external networks while providing wireless network connectivity for devices.
• Antennas: Used in collaboration with routers and access points to transmit and receive wireless signals.
• Wireless Network Interface Cards: Wireless adapters in individual devices that allow the device to connect to a wireless network.
• Client Devices: Wireless enabled devices. Eg computers, phones.

Describe two hardware components the school will need to implement the wireless network. (EXAM Answer):

(Wireless) router;

A central hub for all the computers to connect to;

Enables wireless network packet forwarding and routing;

Wireless Network Interface Card (NIC);

To allow the computer to ‘talk to’ the (wireless) router;

Wireless access points;

allow Wi-Fi devices to connect to a wired network;

Wireless repeaters;

To expand the reach of the network;

Software Components

• Device Driver: Provides a software interface to hardware devices, enables operating systems to access hardware functions without needing to know precise details about the hardware device.
• Firmware: A computer software that provides low level control for a device's specific hardware. Firmware can either provide a standardized operating environment for devices with more complex software. Or for devices with less complex software, firmware can act as the entire operating system performing all of its functions.

Wifi Characteristics

• Used by devices for a wireless network connection.
• Most preferred and very suitable for homes.
• Allows relatively slow to fast data transmissions based on its version.
• Backwards compatible with older wifi standards.

Disadvantages Exam Answer:

May cause security issues;

Due to multiple users having network access from their “unsecured” devices;

Advantages (Exam Answer):

The ability to use their own devices at school; The ability to access the school network from anywhere in the school; No cables laid, so reduces the risk of tripping over cables; Numbers of connections are not limited to cable ports, so greater numbers of students can connect at any given time;

Outline two methods the school could employ to prevent network data from being accessed over their wireless system. Exam Answer:

Use of encryption; So that data cannot be understood if it is intercepted; Use of user authentication/usernames and passwords; To prevent unauthorized access to the system; Setting up a file of accepted MAC addresses; To only allow access to the network by registered mobile devices;

Worldwide Interoperability for Microwave Access

• Designed for large distance and high speed wireless network connection.  
• Cost effective for the geographical distance it provides network connectivity for.
• Rivaled by Long Term Evolution (LTE)
• Can be used as a wireless variant of DSL phone lines.

Protocols

• Provide a set of rules that govern how devices in networks communicate with each other. Without protocols it would be difficult for devices to exchange information and data efficiently.

Why are they used (Exam Answer):

• To provide a set of rules/procedures;
• To enable different computers to understand each other during data transfer / enable successful communication;
• (enable successful communication/data transfer between electronic devices)

Why are Protocols Necessary

• Ensures Interoperability: Protocols ensure that devices can communicate with each other regardless of their hardware or software components.
• Facilitating Error Detection and Correction: Provides mechanisms that detect and correct errors that may occur during data transmission to maintain its integrity and make sure the data is sent.
• Ensuring Security: Provides measures to protect devices against unauthorized access and data tampering.
• Allows for Efficient Communication: Protocols optimize the way devices communicate with each other to maximize speed of data transmission.

Importance of Network Protocols (Essential Functions)

• Ensure Data Integrity: Ensure the overall completeness, accuracy and consistency of data.
• Regulate Flow Control: Manages the rate of data transmission between two nodes to prevent fast senders from overwhelming slow receivers.
• Manage Deadlock: Fixes instances of deadlocks which is defined as the event of two processes waiting for the other to complete before proceeding.
• Manage Congestion: Fixes congestion which is defined as the even when a node is carrying more data than it can handle which deteriorates service quality.
• Manage Error Checking: Employs techniques to ensure the delivery of reliable data over unreliable communication channels.

Outline, with an example, the function of protocols (exam answer).

Protocols are a set of rules; To facilitate a process being carried out correctly; (Used in each layer to ensure communication;) For example (in the physical layer) the protocols could define the methods for opening and closing communication;

Why are protocols necessary (Essential Functions):

Protocols define the rules that govern network communication (for example, packet format, type and size, what happens when an error occurs, and which part of the network is supposed to handle the error and how);

Computer networks consists of various types of equipment (such as routers, switches, hubs and network interface cards) and the equipment comes from different vendors, but they must all work together or the network does not operate correctly;

Protocols work in layers (the highest being what the user sees, and the lowest being the wire that the information is transferred along) and these layers communicate with each other according to the rules (allowing communication to occur accurately and efficiently);

Transmission Medium

• Metal Conductor:

• Medium Level of security
• Susceptible to interference
• Cost Effective
• Relatively fast data transmission

• Fibre Optic:

• Very secure (Exam Correct)
• Generally fragile
• Expensive
• Very fast data transmissions (Exam Correct)
• Less Susceptible to Interference (Exam Correct)
• Supports higher bandwidth (Exam Correct)
• Allows Transmission over longer distances (Exam Correct)

• Wifi (Radio Waves):

• Unsecure
• Susceptible to interference
• Cost effective
• Slow data transmissions

Packet Switching

• Packet switching is a method of breaking down data into packets before forwarding them over a network where it is resembled. Data is broken into packets which consist of a head and payload. The header contains the destination I.P. address where the payload is extracted and reassembled to be used by the destination software.

How Data is transmitted by packet switching

• Network communication is broken down into packets. Every packet has a header and data. The header of a packet contains (among other information) the source and the destination IP address of the packet. The packet is ROUTED to it's destination by a collection of routers, all using an agreed-upon protocol of communication. Packets are reassembled at the destination and de-encapsulated (unzipped) into a network request your operating system (and application) can understand.

Exam Answer:

Data is organized in specially formatted units (data packets);

Each data packet contains data and information such as the sender and receiver address, size of packet, sequence number, control codes, etc.;

which are routed from source to destination using network switches and routers;

network switches and routers determine how best to transfer the packet between a number of intermediate devices (routers and switches) on the path to its destination (rather than flowing directly over a single wire on the path to its destination);

data packets are reassembled at destination;.

If any packets are missing, they are retransmitted;

Why is Data Compression Necessary

• Compressing data before transmission reduces the amount of data that needs to be transmitted and therefore:

• Reduces Bandwidth Requirements: Less data requires less bandwidth which is especially useful for networks with bandwidth restrictions.
• Improves Transmission Speeds: Less data that needs to be transmitted requires less time to transmit.
• Reduces Storage Requirements: Less data requires less storage space.
• Reduces Costs: Less data that needs to be transmitted or stored requires less costs.

Why is Compression Necessary (Exam Answer):

Compressing a data file reduces the file size;

The reason for compression when transmitting data is to save on transfer times;

As it reduces the number of bits needed to represent data (when compared with the original data);

The amount of time it takes to send a file over the network depends on the size of the transmitted file, so the amount of time needed to transmit the file is reduced /transmission of a compressed file takes less time than transmission of that same uncompressed file;

Compressing data involves modifying/restructuring files, so that they take up less space; And this results in cost savings in cloud storage;

To take up less bandwidth;

Because data compression reduces the size of files to be transmitted over a network;

Virtual Private Network (VPN)

• A VPN extends a private network over a public network enabling users to send and receive data across public networks as if their computers were directly connected to a private network.

Required Technologies for a VPN

• Encryption: Process of encoding data in order to allow only authorized users to access it and making it unreadable for unauthorized users.
• Tunneling: Tunneling allows private network communications to be sent over public networks through means of encapsulation.

Identify two technologies the school would require to provide a VPN. Exam Answer

Client VPN software (to make a secure remote connection); VPN-aware routers and firewalls (to permit VPN traffic to pass); VPN appliance/server (to handle incoming VPN traffic);

Encryption protocol IPSec or SSL;

Exam Answer:

Encryption;

If data intercepted, it will not be readable;

encrypting each encapsulated data packet’s content with an encryption key (the key is shared only between the VPN’s server and clients);

Tunnelling software;

A VPN hides a user’s data by encrypting it with a tunnel created between the user’s device and the VPN’s web server (The user then takes on the IP address of the web server (rather than their true IP), and this leads to one advantage of a VPN (namely that a user can appear to be in a different geographic location than they are actually located in);

How would a VPN allow communication between Europe and Asia office (Exam ANswer):

VPN allows secure communication with the Head Office in Asia;

A VPN is the company’s private network that uses a public network (in this situation the Internet) to connect remote sites/employees together;

Privacy is protected using VPN tunneling;

VPN uses encrypted connections routed through the Internet from the company's private network (Europe)to the remote site in Asia (or employee);

Hiding IP addresses to prevent unwanted exposure and data leaks;

Data passed through a network can be encrypted - anyone intercepting the encrypted data cannot read it;

A VPN/ tunneling allows the employee’s device to appear to be part of the internal company network; Thus affording him/her full access to the network resources;

Multiple exit nodes / hidden IP addresses/encrypted connections;

Make it hard to distinguish where the data was generated;

Benefits of a company using VPN (Exam Answer):

A VPN improves data security;

By passing the company’s data through a hidden tunnel;

And encrypting the internet traffic inside encapsulated data packets; making them unreadable if accessed/intercepted by unauthorized persons.

A VPN improves the company’s productivity; as the workers will not have to be in a particular location to get to be productive;

Remote access to data and resources (from any location); Normal access of materials on the network; as though the user was using the network on site;

VPN is not dependent on any particular network or Wi-Fi connection to work/ can be used on any type of device;

Advantages of VPNs

• Increases privacy while online.
• Increases security while online.
• Provides flexible work hours.

Disadvantages of VPNs

• Promotes isolation.
• Promotes distractions.
• May make forming professional relationships more difficult.

Resource Management

Identify the resources that need to be managed within a computer system.

Primary Memory

• Where all data or programs currently being processed are stored.
• Effect on system if too limited:

• If there isn't sufficient primary memory while the OS is attempting to execute a process, the OS will begin to use secondary storage by means of virtual memory which is much slower.
• If this doesn't provide enough memory either the OS is not able to process the instruction and run the program won't be executed. (Finite amount of memory)

Secondary Memory

• Where data or programs can be stored when the power is turned off.
• Effect on system if too limited:

• No place to “save” work so data may be lost.
• May prevent the OS from using secondary storage as virtual memory if ram fills up
• Limits how much data can be stored.

CPU 

• When the OS runs a piece of software it must find the program file in storage, load it into main memory and instruct the CPU to execute instructions.

• Effect on system if too limited:

• In order to execute instructions the CPU must process them. If the CPU isn't processing instructions fast enough the user may experience lag or failure and other processes may also be impacted. (Cant Process at a Sufficient Speed)

Bandwidth:

• Bandwidth is how much data can be sent in a certain time-frame within networks.
• Effect on system if too limited:

• The consequences of limited bandwidth is most commonly lag. If a process is waiting on a certain amount of data in a certain amount of time due to limited bandwidth it must employ buffering strategies. (Limited bandwidth)

Screen Resolution:

• The measurement of the number of pixels in the height x width of the display.

• Effect on system if too limited:

• If there are inadequate resources to render video processes the rendering may be blurry and choppy. Inadequate resources typically arise from the lack of or poor video card. The CPU can only process a limited number of instructions per second, a video card is dedicated to executing video processes and thus speeds up the rendering process and improves performance. (Inadequate resources)
• Limiting screen resolution reduces the number of pixels that can be displayed resulting in a lower quality image that appears more pixelated.

Sound Processor:

• Manages the use of and access to audio devices. Sound reproduction is done by a sound processor, freeing up the CPU to do other calculations
• Consequences if too limited:

• The CPU is taxed with having to process sound slowing down the system overall.
• Sound quality would also deteriorate.

Graphics Processor

• Does complex graphic processing like 3d rendering.
• Consequence if too limited:

• Similarly with the sound processor, if the graphic processor is too limited the CPU must pick up its weight which deteriorates overall system performance and display.

Cache

• Contains the instruction/data that the CPU is likely to request from RAM.
• Consequence if too limited:

• The CPU will have to wait for instructions to be fetched from RAM which is slower than cache so the system slows down overall.

Network Connectivity

• Every network card connects to a particular type of network media.
• Consequence if too limited:

• Limited connection types limit the way data can be sent or received in a system.
• Speed may also be negatively affected.

Evaluate the resources available in a variety of computer systems 

Identify the limitations of a range of resources in a specified computer system.

Describe the possible problems resulting from the limitations in the resources in a computer system.

Outline OS resource management techniques: scheduling, policies, multitasking, virtual memory, paging, interrupt, polling.

Operating System Management Techniques

• Scheduling: The method by which work is assigned to resources that complete the work. The main purpose of scheduling is to minimize resource starvation and ensure fairness amongst parties utilizing resources.
• Policies: The separation of policy and mechanism is a design strategy in computer science. Policies choose the activities to perform in a computer and mechanism refers to how the chosen activities should be executed.
• Policies are strategies that determine which activities should be performed, guiding decisions about which operations are authorized and how system resources are allocated.
• Multitasking: The idea of executing multiple processes simultaneously. Operating system uses multitasking by running multiple programs at a time to increase performance.
• Virtual Memory: The OS is able to extend available memory by creating virtual memory on a portion of the hard disk. Virtual memory is able to function like primary memory allowing the computer to run larger applications even when physical memory is limited.
• Paging or Swapping: When a computer runs out of available RAM, the OS moves data from RAM to the hard disk to free up space. This temporarily stored data is kept in a special area called a pagefile (or swap file). When the OS needs that data again, it must retrieve it from the hard disk. However, if there is still not enough free RAM, the OS must first move other less-needed data from RAM back to the hard disk to make room. This process of moving data between RAM and secondary storage is paging or swapping.
• Paging: transferring fixed-sized memory block, swapping: transferring entire processes.
• Interrupt: The OS manages hardware interrupts, which are signals made by hardware devices to notify the OS of an event that needs immediate action. The OS processes the interrupt and takes appropriate action.
• Polling: A technique where a system repeatedly checks the status of a device, process, or resource at regular intervals to see if it requires attention. This contrasts with interrupt-driven processing, where the device notifies the system only when it needs action.

Outline two resource management techniques that are likely to be carried out by the operating system of a desktop computer (EXAM Answer):

Virtual memory;

to enable the hard drive to act as primary memory if required;

Paging;

scheme by which a computer stores and retrieves data from secondary storage for use in main memory;

Multitasking;

to enable more than one application to run at the same time;

Scheduling (method by which work is assigned to resources that complete the work);

to determine which process will own CPU for execution while another process is on hold.;

Policies (ways to choose which activities to perform);

according to which decisions are made about which operations should be authorized/ which resources should be allocated;

Interrupt handling;

so that urgent tasks required by parts of the system may be executed;

Polling; to sampling the status of an external device;

The function of an Interrupt (Exam Answer)

An interrupt is a signal to the CPU sent by hardware or software;

The function of an interrupt is to alert the CPU to suspend execution of the current program;

And to transfer the control to the interrupt handler (which saves the state of the current program to the interrupt stack, services the interrupt and resumes the normal CPU activity);

Discuss the advantages of producing a dedicated operating system for a device

Dedicated Operating System for a Device

• Dedicated operating systems are designed to operate on small machines with less autonomy like phones.

Advantages of Dedicated Operating Systems

• Size: A dedicated operating system is designed to only the necessary components it needs to perform its specific function allowing it to be smaller in size.
• Speed: By focusing only one performing specific tasks the operating system is highly optimized for its performance which increases its speed.
• Customization: A dedicated operating system can be highly customized to meet the precise needs of its application. Customization allows developers to only include features that are essential for its intended use which increases efficiency and user experience.
• Security: With fewer components in the operating system there are fewer opportunities of security vulnerabilities and makes it easily securable. Furthermore, the OS controls and prevents access, input and output. (Exam Correct)

Identify Exam Answer:

Makes maximum use of the available (limited) memory to provide the features needed for the phone; Does not waste memory space with unwanted/inappropriate features; Ensures a higher level of security; Makes efficient use of hardware equipment; Suited to available hardware equipment;

Outline how an operating system hides the complexity of the hardware from users and applications.

How the OS Hides Complexity of Hardware Resources from Users and Applications

• The operating system hides the complexity of hardware by providing abstractions and interfaces. It uses a hardware abstraction layer to manage different hardware components, virtual memory management to eliminate the need for applications to manage physical memory, and a file system abstraction to simplify storage access. Additionally, the operating system provides user interfaces to facilitate user interaction without knowledge of hardware and implements network protocols and security measures to allow users and applications to operate seamlessly.
• A drive letter is a single alphabetic character (A–Z) assigned to a storage device or partition on a computer. Each drive or storage medium is identified by a unique letter to help the operating system and users easily access and manage different storage devices.
• The Java Virtual Machine (JVM) is a software component that interprets and runs Java bytecode on a computer. The JVM acts as a bridge between the Java program and the computer’s processor. Each operating system has its own JVM, allowing Java programs to run on any platform without modification

How OS hides complexity Exam Answer :

The virtualization of real devices;

such as the use of drive letters for partitions to represent a virtual hard drive;

Use of icons;

to represent peripherals/to access different drive

Abstract Data Structures

Define the term dynamic data structure.

Static Data Structure

• Static data structures store a set of data where the memory size allocated to the data is static. (Static data structure is given a fixed area of memory which it can operate within)

Dynamic Data Structures

• A dynamic data structure is a data structure that can change in size during runtime, allowing efficient memory usage by allocating and deallocating memory as needed.

• Dynamic data structures are designed to facilitate change of the data structure during run time. In dynamic data structures neither the data nor the initial memory allocated is static. You can change existing elements or add and remove elements, in general you can do any type of operation on the data structure without considering the memory space allocated initially.

Identify Characteristics of Dynamic Data Structures Exam Answer:

Dynamic data structure does not have predetermined size/ allows memory use to change as needed (no fixed size) / if more space is required to store more data, it can therefore increase;

Can be expanded until all the available RAM is used;

As records can be dynamically added/deleted the memory is better used because there are no wasted / missing spaces as in an array;

Memory is allocated to the data structure as the program executes (run-time);

Elements of a dynamic data structure are sequentially accessed;

Elements of a dynamic data structure are stored in memory locations that are chained together but not necessarily physically contiguous;

Compare the use of static and dynamic data structures.

Static VS Dynamic

• Static data structure is given a fixed area of memory which it can operate within which is not expandable, the location of each element is fixed and known by the computer. On the contrary, dynamic data structures are given a flexible area of memory which it operates within. It is possible to expand or contract the area of memory as needed with dynamic data structures.

The difference explain version (exam answer):

Memory is allocated to the static data structure in compile time (a pre-set amount of memory/fixed size);

Memory is allocated to the dynamic data structure at run-time;

The size of a static data structure can never change during run-time whilst the size of dynamic data structure can be randomly updated during run time which makes efficient use of RAM;  

Memory allocated to a static data structure is fixed and always available for use by the structure. Elements can be accessed either directly (random access) or sequentially, depending on the algorithm.

In contrast, elements in a dynamic data structure must be accessed sequentially, as direct access is generally not supported due to the way memory is allocated and linked.

As a result, algorithms that use dynamic data structures are often slower during execution compared to those that use static data structures, especially when frequent element access or searching is involved.

Construct algorithms using pre- defined sub-programmes, one- dimensional arrays and/or collections.

Array

• Arrays are used to hold values of the same type in contiguous memory locations. Arrays allow us to create lists of variables without needing to give each variable a unique name.

Two-Dimensional Array

• A two-dimensional (2D) array, also known as a matrix, is a data structure that organizes and stores elements in rows and columns. It can be visualized as a table.

Describe the characteristics and applications of a stack.

Construct algorithms using the access methods of a stack.

Stack

• An abstract data type that serves as a collection of elements with two principle operations. Push, adds an element to the collection. Pop removes the most recently added element of the stack. The order in which elements are removed in the pop operation follows, last in - First out.

Stack Applications Exam Answer:

Holding all data of a function/method call;

simulation of recursion;

Conversion of expressions (infix to postfix, infix to prefix, etc)

Evaluating expression;

Parsing;

Describe the characteristics and applications of a queue.

Construct algorithms using the access methods of a queue.

Queue

• An abstract data collection where the entities in the collection are kept in order. The two principle operations of a queue are enqueue which adds an entity to the rear terminal position and dequeue which removes the entity in the front terminal (first in first out).

Explain the use of arrays as static stacks and queues.

Arrays can be used to implement static stacks and queues, but they have a fixed size, meaning they cannot grow dynamically. A stack, which follows the Last In, First Out (LIFO) principle, uses an array where elements are added (push) and removed (pop) from the top. A queue, which follows First In, First Out (FIFO), uses an array where elements are added at the rear (enqueue) and removed from the front (dequeue). While simple, static stacks and queues suffer from overflow issues when full, and wasted memory when elements are removed, making dynamic structures like linked lists more efficient for scalable applications.

Describe how linked lists operate logically.

Sketch linked lists (single, double and circular).

Linked List

• A linked list is a linear collection of self-referential structures called nodes each pointing to the next node by means of a pointer. It is a data structure consisting of a group of nodes which together represent a sequence.

Characteristics of a Linked List (Exam Answer):

• In exams linked lists are assumed to be dynamic.
• Access to items in a linked list is sequential.
• Hence searching for an item in a linked list is slower that searching for an item in a static array.
• Binary search doesn't work.

Doubly Linked List

• A linked list that consists of a set of sequentially linked records called nodes

Circularly Linked Lists

• When the last node of the linked list points to the first node of the list.

Inserting Into a Linked List

Traverse the list (from the beginning) to find the place to insert a new node;

1. Inserting into an empty list

• Algorithm sets both the head and tail to point to the new node.

2. Inserting at the beginning

• The new node is inserted before the current head node and the head link updates so that it points to the new node while the new node points to the previous head node.

3. Interesting at the end

• The new node is inserted right after the current tail node and the tail link updates so that it points to the new node while the new node points to the previous tail node.

4. Inserting in the middle

• When inserting a new node the head and tail link are unchanged. Instead the node behind the new node updates to point to the new node while the new node points to the node ahead of it that was unlinked by the node behind it.

Explain why deleting the first node in this list is different to deleting other nodes

External pointer (First) must be changed;

And set to the pointer in the link field of the first node (Asparagus) which points to the second node/Lettuce;

Compare the use of arrays and linked lists (Exam Answer)

In an array, memory is assigned during compile time(predetermined) whilst in a linked list it is allocated during execution/runtime;

Arrays are of fixed size whilst linked lists are flexible and can expand and contract its size;

Array requires less memory (due to actual data being stored within the index in the array) whilst there is a need for more memory in linked list (due to storage of additional next and previous pointers/references);

Elements are stored consecutively in array whereas elements are stored randomly in linked lists;

Memory utilization is inefficient in the array whilst memory utilization is efficient in the linked list;

Accessing an element in an array is direct (fast) while accessing an element in linked list is sequential/linear (slower) /to get into the nth element only the array name with index within the square bracket should be written whilst a linked list (to get the nth element) should be traversed starting from the beginning of the list, and traversing through the list until found/ ;

Operations like insertion and deletion in arrays consume a lot of time whilst the performance of these operations in linked lists is fast;.

Describe how trees operate logically (both binary and non-binary).

 Tree

• An abstract data type that simulates a hierarchical tree structure, with a root value and subtrees of children with a parent node, represented as a set of linked nodes.
• Data is organized from the root down to multiple levels of children, forming subtrees.
• Traversing a tree follows structured algorithms to visit nodes in a particular order.
• Binary Trees: Each node has at most two children
• Non-Binary Tree: Each node can have more than two children.

Why is a binary tree appropriate for an address book (Exam ANswer):

Time efficient searching / traversing for a contact in an address book;

Each iteration / comparison allows the size of the search to be reduced (by skipping about half of the remaining contacts);

Fast/easy addition / removal of contacts in an address book;

Quick search for the leaf node / empty node where a new contact can be placed / for the node containing the contact to be deleted;

Contacts can be listed / output in alphabetical order/ fast sorting;

using inorder traversal;

The Benefits of Searching a Binary Tree, Compare to a Stack, for a Specific Item(Exam):

Example answer 1 (time efficiency):

The data in the binary search tree(BST) is ordered;

Such that as each node is checked for the item, half of the remaining nodes are ignored; But each element in the stack has to be checked;

Which, for large data sets, may be inefficient compared to the BST;

Example answer 2 (memory efficiency):

Each element on the stack has to be popped off/removed from the stack to be checked for the searched item;

When the item is found the stack will be empty/stack contents will be changed; When an element in the BST is checked for the item it is not removed from the BST;

So there is no need to create an additional copy of the BST (but a real copy of the stack must be created which for large data sets may be inefficient);

Define the terms: parent, left-child, right-child, subtree, root and leaf.

Parent

• A node that has one or more child nodes.

Left-Child

• The left node is directly connected to a parent in a binary tree.

Right-Child

• The right node is directly connected to a parent in a binary tree.

Subtree

• A smaller tree that exists within a larger tree, originating from any node.

Root

• The topmost node in a tree, having no parent.

Leaf

• A node with no children, representing the end of a branch.

State the result of inorder, postorder and preorder tree traversal.

Sketch binary trees.

Describe the characteristics and applications of a collection.

Collection

• An object that groups multiple elements into a single unit.
• A collection is a data structure that stores multiple elements and allows efficient data manipulation. It can be ordered or unordered, supporting operations such as adding, removing, searching, and iterating through elements. Collections can have a fixed size or be dynamic.

Collection is a container of discrete values;

A collection typically stores elements of the same data type, such as primitive values or structured data.

However, collections can also store objects of different types if they use pointers or references.

Collections have a set of methods that define operations performed on the elements/objects of that collection; Such as adding/removing elements to/from collection, comparing elements of collection, searching, etc;

Which reduces programming effort (because implementations of data structures and algorithms are provided);

Which increases performance of the program (because efficient implementations are provided);

Applications

• Collections have many real-world applications, including data storage and retrieval, where lists and dictionaries help manage user records and search queries. They are widely used in sorting and searching algorithms, enabling quick data organization. In computing, collections power queues and stacks, essential for managing tasks, function calls, and undo/redo operations.

Queue Applications (Exam Answer):

Print queues (a number of print jobs on a queue instead of waiting for each one to finish before specifying the next one);

Queues are used in CPU scheduling algorithms;

Handling of interrupts in real-time systems (the interrupts are handled in the same order as they arrive, first come first served);

Computer modelling of physical queues (supermarket checkouts) (call centre phone systems use queues to hold people calling them in an order, until a service representative is free);

Queue is used for synchronization when data is transferred asynchronously between two processes (for example IO Buffers, file IO);

Discuss the need for sub-programmes and collections within programmed solutions.

• Sub-programmes and collections improve the structure, efficiency, and scalability of code.
• Sub-programmes help break down complex tasks into smaller, manageable parts. This improves code readability, makes it easier to debug, and reduces redundancy.
• Collections are used to store and organize groups of data. They allow programmers to handle large amounts of data efficiently through operations like searching, sorting, adding, or removing elements

Construct algorithms using the access methods of a collection.

Construct algorithms using pre-defined sub-programmes, one-dimensional arrays and/or collections.

Identify a situation that requires the use of recursive thinking.

Recursion

• The process of a subroutine calling itself.
• A method where the solution to the problem depends on solutions to smaller instances of the same problem.

Outline one disadvantage of solving problems recursively (exam answer).

More difficult/complicated to code; if the data structure being processed is not recursive; It is difficult to find bugs; particularly while using global variables; Can use more memory (than iterative solution) when executed; because every recursive call increases the call stack; Recursion to a deeper level will be difficult/impossible to implement; if the call stack space on the system is limited; Slower execution / using a recursive function takes more time to execute; as compared to its non- recursive/ iterative counterpart;

Identify recursive thinking in a specified problem solution.

Trace a recursive algorithm to express a solution to a problem.

Control 

Discuss a range of control systems.

Control System

• Manages, commands, directs or regulates the behaviour of other systems using control loops.

Control Loop

• A programming structure that repeats a block of code multiple times based on specific conditions.

Traffic Light

• In a simple traffic light, the input is a timer which dictates what lights are turned on. More complicated versions may have sensors that detect cars on the street to allow for a more dynamic timing so that pedestrians do not have to wait when there are no cars around.

Global Positioning System

• A satellite-based navigation system. GPS works by using a network of satellites that orbit the Earth and continuously transmit signals containing their location and the exact time. A GPS receiver, such as one in a smartphone, picks up signals from these satellites. By calculating how long each signal took to reach the receiver, it can determine the distance to each satellite. The receiver then uses these distances to pinpoint its exact position on Earth.

Explain how GPS works (Exam Answer):

The GPS receiver in a train takes the information from the satellite/ picks up the signals from (at least) 3 satellites;

The signals transmitted are: time of transmission, coordinates of the satellite;

The difference between the (atomic) time of transmission and (atomic) time of receiving the signal is used to calculate the distance;

The method of trilateration is used to determine position from the distance to satellites/ is used to determine the train’s exact position/ is used to calculate position of the train through equation resolution on a sphere;

Automatic Doors

• Contains sensors that constantly check whether a person is in front of the door. If there is, an actuator, which in this case is a motor, opens the door.

Heating Systems

• Compares the actual temperature of a room with the target temperature and takes the necessary action to heat the room until the target temperature is reached.

Taxi Meter

• Calculates the passengers fair based waiting times or distance travelled.

Elevator

• The control system of an elevator takes input from various buttons and position sensors and gives different outputs. Outputs include the display of the current floor, direction and control of the door and the motors that drive the cart up and down.

Washing Machine

• The microcontrollers in a washing machine get input from the user about how long it washes, the washing temperature and speed and then bring it to fruition through motors.

Process Controller

• A control system that is in charge of keeping a specific process's output within a desired range. Through taking in a variety of inputs, a process controller allows for the mass production of consistent goods.

Device Drivers

• A device driver is an interface between the Operating System and a hardware device. Inputs are called by a program. The driver then translates this for the device and gets data back. This driver then presents this data to the program.

Cleaning Robot

• Infrared sensors can detect objects in front of it. If the robot senses an object it processes this data and moves away in a different direction.

Outline the uses of microprocessors and sensor input in control systems.

Microprocessors

• Microprocessors are the central processing unit of control systems. They process input data from sensors and execute control algorithms to control the output of the system.

Sensor Input

• Sensors are used to monitor physical variables in the system such as temperature or position. The data obtained by sensors are then processed to make control decisions.

Evaluate different input devices for the collection of data in specified situations.

• Heat: measures temperature, e.g. central heating, fire alarm
• Humidity: measures water vapour in the air, e.g. greenhouses, swimming pool halls
• Infra-red: measures heat (a type of radiation), e.g. security alarm systems
• Light: brightness, e.g. security lights
• pH: acidity levels, e.g. environmental monitoring
• Pressure: force applied on the sensor, e.g. automatic doors, alarm systems
• Smoke: particles in the air, e.g. fire alarm
• Sound: sound pressure level, e.g. noise pollution monitoring, voice controlled systems, alarm systems
• Tilt: angle of tilt, e.g. aircrafts, alarm systems installed in windows
• Touch: more sensitive than pressure/detects contact, e.g. robots

Describe two types of sensors used in the floor-cleaning robots Exam Answer. 

Proximity sensors/ range sensors;

Which are used to determine how close an object is to the sensor;

Optical sensors /Photocells and other photometric devices (often used in conjunction to proximity sensors);

which are used to detect the presence or absence of objects;

Tactile sensors / Contact sensors / Bumpers;

which are used to determine whether contact is made between sensor and another object;

Touch sensors;

which indicate when contact is made;

Force sensors;

which indicate the magnitude of the force with the object;

Machine vision;

which is used in robotics for inspection / parts identification / guidance (accept other uses);

Explain the relationship between a sensor, the processor and an output transducer.

Relationship Between a Sensor, the Processor, and an Output Transducer

• In a control system, sensors, processors, and output transducers work together to measure, interpret, and respond to changes in the environment.

• A sensor is an input device that detects physical changes such as temperature, light, sound, pressure, or movement and converts them into an electrical signal. The conditioned signal is then sent to the processor.
• The processor is the brain of the system. It receives the sensor's signal, interprets it based on programmed instructions, and makes decisions about what action to take.
• Based on the processed data, the processor sends commands to an output transducer, also known as an actuator. An output transducer is a device that converts electrical signals into physical actions, such as sound, movement, light, or heat. Examples include motors, speakers, buzzers, or heaters.
• In summary, the sensor detects, the processor decides, and the output transducer acts. Together, they create a closed-loop system that allows devices to monitor and respond to the environment automatically.

Rumba scenario, Explain the function of an output transducer in this situation (exam answer).

Output transducer is a device that accepts a (digital) signal from processor;

and turns it into a physical movement;

to make the floor cleaning robot move in different direction;

Exam Answer:

Input from flow/pressure sensors is analog;

Sensor (continuously) collecting data (related to the distance between the two vehicles); Data is converted to digital using AD converter…;

…and sent to the processor;

Processor has access to pre-set data (minimum distance required between the two cars);

Processor compares the input data against stored/pre-set data;

If the vehicle is too close, the processor sends a signal to an actuator to apply the brakes/ an output signal (for example, warning light on the dashboard/ audible warning) to the driver to apply break;

The result of processing is in digital form so it should be converted (by AD convertors) into analog form;

If the car has fallen back from the car in front, the processor sends these signals to an actuator to apply acceleration/ an output signal to the driver to apply acceleration;

This process is constantly looped (feedback loop);

*Remember water content scenario, waters until maximum range is reached (most appropriate to the scenario)

Describe the role of feedback in a control system

Feedback occurs when the output of a system is fed back into the input, creating a loop of cause and effect. This allows the system to adjust its behavior based on its own performance. The output is continuously compared to the desired (target) value, and the error is calculated. The error is used to adjust the system output, aiming to reduce the error and bring it closer to the desired value.

Explain (Exam Answer):

The output value is (continuously) compared to the desired value;

To produce an error value/difference between observed and measured;

The controller uses the error value/difference between observed and measured;

To determine the new input to the system;

Feedback Loops

1. Open-Loop Systems: perform actions based on pre-set instructions without using feedback to adjust its output. It cannot correct errors or respond to changes in the environment. A microwave heating food for a set time, regardless of how hot the food actually gets.
2. Closed-Loop Systems: use feedback to compare the actual output with the desired output and make adjustments to minimize errors. It is self-correcting and more accurate. A thermostat adjusting heating based on the room temperature.
3. Negative Feedback: A control mechanism where the system reduces the error by adjusting its input to bring the output closer to the desired value. It promotes stability.
4. Positive Feedback: A control mechanism where the system amplifies the change in output by adjusting its input. It promotes instability or rapid change.

Compare a centrally controlled system with a distributed system

Centrally Controlled System

• When all parts of the system are controlled by a center controller/server.

Distributed System

• A computing architecture in which multiple interconnected computers work together to share resources, process data, and perform tasks without relying on a central authority. It enhances scalability, reliability and efficiency by distributing workloads across multiple systems.

Outline the role of autonomous agents acting within a larger system.

Autonomous Agent

• Software entities that carry out a set of operations on behalf of a user with some degree of autonomy, and in doing so employ some representation of the user’s goal.

Features of Autonomous Agents (Wiki actually hit the nail on the head here)

• Autonomy: Agents activate alone for a task and select tasks themselves based on predefined criteria without human intervention.
• Reactive Behaviour: Agents sense and react to the environment they are in.
• Sociality: Agents can interact with each other through communication in modes such as competition, coordination and cooperation.
• Persistence: The code describing an agent runs continuously like a process and is not executed by human input.

Outline features of Autonomous Agents (Exam Answer):

Reactive behavior;

autonomous agent senses the environment and reacts;

Autonomy;

autonomous agent activates alone for a task / is not invoked for a task / selects the task itself / operates without human supervision;

Persistence;

autonomous agent is a programmed device and the software describing an agent runs continuously;

Sociality;

autonomous agent can interact with other agents through communication / it can work in coordination and cooperation with other agents;

Discuss the social impacts and ethical considerations associated with the use of embedded systems.

Tagging Prisoners

• P: allows non-dangerous criminals to move.
• P: reduces the number of criminals that need to be in prison.
• P: allows for continuous tracking.
• N: Loss of freedom of movement
• N: Could possibly be hacked to track innocent people
• N: Tracking data could be sold off to make money.

Surveillance

• P: Allows for greater security
• P: Could be used as effective evidence in court cases
• P: Allows fewer people to monitor others.
• N: Loss of privacy
• N: Could be hacked and used for harmful purposes
• N: Could be used to spy on people.

Closed Circuit Television (CCTV)

• Deters criminal activity.
• Enhances public and property safety.
• Assists law enforcement with evidence for investigations.
• Helps monitor and manage high-risk or crowded environments.
• Provides reassurance and a sense of security to the public

• Raises privacy concerns due to constant surveillance.
• May lead to reduced personal freedom and a sense of being constantly watched.
• Potential for misuse, such as unauthorized access or sharing of footage.

Programming

Higher lvl & Lower lvl Languages:

• Higher level languages are independent of a particular type of computer, higher level languages more closely resemble a human language, thus, are easier for humans to code and understand. The amount of abstraction defines how “high level” a language is. Higher level languages come with the drawback that they must be translated into machine readable code.
• Lower level languages provide less abstraction and are therefore harder for humans to code and understand. However low level languages require little to none translation into machine readable code.

Why do we need higher level languages (Exam Answer):

Higher level languages are closer to human language;

So programmers find them easier to understand/work with than lower level languages;

Source Code

• What a developer writes.

Compiler

• Application that turns source code into machine readable code.

Assembly

• A low level source language specific to a machine or application.

Bytecode

• A low level binary representation of code.

Machine Code

• A binary representation of code that can be run directly by hardware.

Interpreted Language

• Interpreted languages (eg. python) use an interpreter to translate into machine code. Interpreters run through code line by line and execute each command.  

Compiler VS Interpreter

• A compiler translates the entire source code into machine code before execution resulting in faster execution because there is no translation during runtime.
• An interpreter translates code line by line during execution making it easier to detect errors but slows down the program.

Standards Missed/Miscellaneous

Outline the need for a translation process from a higher level language to machine executable code

Exam Answer:

• A translation process is needed because high-level languages are human-readable but not executable by computer hardware.
• The code must be translated into binary/machine code, which is the only language understood by hardware.
• Translation allows for successful execution of instructions by the CPU.

Discuss the social and ethical issues associated with the introduction of new IT systems.

Discuss the social and ethical issues associated with a networked world.

Ethical and Technical Issues of Sharing Online (Exam Answer):

• Ethical issues: Anyone can access the media; privacy concerns arise if consent was not given.
• Others may not wish to have personal content online, and it may be manipulated or misused.
• Technical issues: Videos/images may not load due to poor internet connection, browser issues, or lack of proper software.
• Server limitations (e.g., file size restrictions) can prevent uploading or viewing.

Inserting into a Binary Tree (Not anywhere in standards but appeared on Exam):

• Award [6] max.
• Award [1] for a loop (to input all the data)
• Award [1] for placing the inputted data into a newly created node
• Award [1] for setting the root node to the new node(if the tree is empty/ no root node) Award [1] for start searching from the root node
• Award [1] for searching for the empty location in the left subtree if the input score is higher than the current value
• Award [1] for inserting the new node in the left subtree when the proper location is found Award [1] for searching for the empty location in the right subtree if the input score is lower than the current value
• Award [1] for inserting the new node in the right subtree when the proper location is found
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Explain the possible consequences of failing to involve the end-user in the design process

Outline version:

The software may not work as expected / may not be better than the existing software / may not meet user requirements / expectations;

The software may be missing some key features;

The software may not be user friendly;

Identify three consequences of inadequate testing .

Can lead to software which is not appropriate for the purpose it was intended/can lead to the system not meeting user requirements;

Can lead to (undiscovered) bugs in software/errors in the system;

Can lead to end user dissatisfaction;

Can lead to reduced (employee) productivity;

Can lead to decreased reliability of the organization;

Discuss centralized vs. decentralized processing in control systems

Cars have many automated features to improve the driving experience. One example is the use of headlights that automatically switch on and off. Some cars have adaptive cruise control. This uses RADAR technology and a processor to ensure the car stays the same distance away from the car in front.

Importance of the .isEmpty() function (Exam Answer):

Method isEmpty() returns True if there are no elements on the stack, False otherwise;

It is important to call this method in logical expression/condition in algorithm constructs such as branches and loops (if/while);

Before popping an element from the stack / popStack();

To prevent errors/stack underflow/program crash;

Outline two pieces of information that the ATrainAway application could provide to the user.

Real-time information (train number/ route / direction and status (on time / delayed / cancelled);

relating to the arrival / departure of a particular train;

The time next train is due (the next 2/3 times a train will arrive at the station); helps passenger to spend less time waiting on trains;

Should save user's (passenger) most frequented stops and routes;

for quick access to get the next rail trip; Alerts (set); to let you know when a train is nearing the station;

Trip planning (conducted);

through Google trip planner within the app; Information on the nearest station, distance to station/ next train arrival/ next train departure; to help passenger to spend less time travelling/ save time;

Discuss the advantages and disadvantages of using GPS in transportation systems (Exam Answer).

Safer transit;

Trains are tracked and in case of emergency the location can be reached at the earliest and emergency services provided;

More favourable view of transit/helps passenger to get punctuality status of the train/;

GPS can provide worldwide three-dimensional positions (24 hours a day) (in any type of weather);

Sometimes it is too difficult to ensure reliable positioning;

Objects, such as buildings, overpasses, and other obstructions (that shield the antenna from a satellite) can potentially weaken a satellite's signal;

Privacy issues;

Knowing the absolute position of anything, anytime, anywhere;

Explain why abstraction is required in the design of algorithms (Exam Answer).

Abstraction allows us to create a general idea of what the problem is and how to solve it; Abstraction removes all specific detail, and any patterns that will not help in solving a problem. This helps in forming a “model” (If designers don’t abstract they may end up with the wrong solution to the problem they are trying to solve); Abstraction is widely used because there exist a number of “patterns” in programming that keeps repeating in every application/program; The pattern corresponding to an issue can be found, then the abstract solution to it can be found and implemented, and the problem is solved; Most programming languages provide some built-in abstract patterns, which are easy to use (some API provides more advanced patterns); Abstraction is the process of taking away or removing characteristics from something in order to reduce it to a set of essential characteristics; In object-oriented programming, abstraction is one of three central principles (along with encapsulation and inheritance); Through the process of abstraction, a programmer hides all but the relevant data about an object in order to reduce complexity and increase efficiency; The resulting object itself can be referred to as an abstraction, meaning a named entity made up of selected attributes and behavior specific to a particular usage of the originating entity. Abstraction is related to both encapsulation and data hiding;

Outline two advantages of a school using a computer network (Exam Answer):