Computer science topic 1- System fundamentals

Data gathering

The process of investigating and researching current systems through methods such as interviews, questionnaires, document collection, and observation.

Interview

A data gathering method that provides detailed information through two-way communication with key individuals.

Questionnaire

A method of data gathering designed to quickly reach large audiences, allowing for extensive analysis.

Document collection

A process of gathering objective data about the inner workings of a system, such as inputs and outputs.

Observation

A method of data gathering that provides first-hand and unbiased information, though it may influence behaviors.

Requirements specification

An analysis phase that identifies the inputs, processes, outputs, and problems of a system to guide new system development.

Change management

A structured approach to transitioning individuals and organizations to a desired future state.

Compatibility issues

Challenges that arise when older systems (legacy systems) or different systems interact, often requiring data reformatting or causing errors.

Legacy system

An older computer system or software that may be incompatible with newer technologies, leading to issues such as data loss.

Cloud computing

The delivery of computing services over the internet, offering models like IaaS, PaaS, SaaS, and NaaS.

Direct installation

A system installation method where the old system is replaced entirely by the new system with no overlap.

Parallel installation

A method where both the old and new systems operate concurrently, allowing for a comparison of outputs.

Pilot installation

A trial of the new system in a small part of the organization before full-scale implementation.

Phased installation

An installation method where the new system is introduced gradually, replacing parts of the old system.

Data migration

The process of moving data from one system to another.

Incompatible file formats

File types that do not match between systems, which can cause data loss during migration if not handled properly.

Validation rules

Rules that ensure the accuracy and consistency of data, which can become incompatible during migration.

Incomplete data transfer

A common problem during data migration where not all data is successfully moved to the new system.

What is an advantage and disadvantage of using an Interview for data gathering?

Pros- Detailed info, two way communication and face to face

Cons- Time consuming

What is a advantage and disadvantage of using a Questionnaire?

Pro- Data can reach large audienecs quickly and can be used to create extensive analysis. Fast and effective

Cons- Has to be well designed otherwise people may not answer properly or completely

What is a advantage and disadvantage of Parallel Installation?

Pros- If new system fails old system serves as backup (safety net), outputs from both systems can be compared to see if new one is running properly

Cons- It is costly and time-consuming.

What is a advatnage and disadvatange of Direct Installation?

Pros- Minimal time and effort, new system is available immediately

Cons- There is no replacement or backup system to fall back on immediately.

What is an advantage and disadvantage of the Observation method?

Pros- First hand and unbiased information

Cons- Observing may influence things or peoples behaviour leading to unrealistic results

What is an advantage of Phased Installation?

Users can get used to the new system in small stages, and training can be completed gradually rather than all at once.

Cloud computer advantages vs disadvantages

Pros- Convenience, security, backups, collaboration and environmentally friendly

Cons- Security, service outage, storage limits, slow speeds, limited features and less control, provider time zones varying to that of end users causes convinience issues.

List the three types of testing data used in system development.

1. Normal Data

2. Boundary Data

3. Abnormal Data

What is Normal Data?

Data that is within the expected range and should be accepted by the system to ensure correct processing (e.g., entering $75$ for a test score between $0$ and $100$).

What is Boundary Data?

Data that sits at the limits of the acceptable range. This is used to test if the system identifies the exact cut-off points correctly (e.g., entering $0$ and $100$ for a $0$-$100$ range).

What is Abnormal Data?

Data that is outside the normal range or is of an unexpected type. This tests the system's ability to handle errors without crashing (e.g., entering "not a number" or $-5$ into a positive integer field).

Distinguish between Alpha Testing and Beta Testing.

• Alpha Testing: Conducted internally by the developers at the development site before the software is released. Typically done in lab environment. Focused on functional correctness, security aspects and software bugs

• Beta Testing: Conducted by limited group of end-users outside of organization in their own real-world environment to provide feedback on usability and bugs. Focused on unidentified bugs, usability and compatibility issues improving user experience

What is the purpose of User Documentation?

Explains how to use each part of a system, acts as a guide of systems features and characteristics. Poor or confusing documentations slows down implementations and increases support needs

List the three common methods of User Training.

1. Self-instruction

2. Formal classes

3. Remote/Online training

What are the advantages and disadvantages of Self-instruction?

Advantage: It is the lowest cost method and allows for a flexible schedule tailored to the user.

Disadvantage: It requires high user motivation and there is no expert available to help if the user becomes stuck.

What are the advantages and disadvantages of Formal classes?

Advantage: It provides a structured learning environment with direct access to an expert for immediate feedback.

Disadvantage: It can be expensive to organize and requires the user to be away from their desk at a specific time.

What are the advantages and disadvantages of Remote/Online training?

Advantage: It is highly scalable for large organizations and accessible from any location with an internet connection.

Disadvantage: It relies heavily on technical stability (e.g., internet speed) and lacks the personal touch of face-to-face instruction.

List the methods to prevent Data Loss.

1. Backups

2. Removable media

3. Offsite storage

4. Failover systems

5. Online storage

6. Antivirus and updates

7. UPS

8. Monitoring (SMART)

What is the difference between Backups and Offsite storage?

• Backups: Making regular copies of data to a secondary device to recover from local file corruption.

• Offsite storage: Storing those backups in a separate physical location to protect data against disasters like fire or theft at the main site.

What is a Failover system?

A redundant computer system that automatically takes over the functions of a primary system if it fails, ensuring system availability is maintained.

Contrast software Patches and Upgrades.

• Patches: Small updates designed to fix bugs or security vulnerabilities in existing software.

• Upgrades: Major releases that add new features and significant functional improvements to the system.

Local computing

Pros- Security, backups can be controlled, legacy software , software control, feature control

Cons- Cost of hardware, technical support, lack of collaboration

Pilot installation pros and cons

Pro- All features can be fully trailed, If new system dails only a small part of organisation suffers, staff who were part of pilot study can train other staff

Cons- For section that is piloting if system fails there is no backup

Common data migration problems faced

Incompatible file formats, data structure differences, validation rule issues and incomplete data transfer

Data structure differences and validation rule issues

Data migration problems that are regularly occuring

Data structure differences are how data is organized within a system. Without compatibility importing data to new system becomes harder

Validation rules ensure data accuracy and consistency.

Tips for successful data migration

Planning, data cleaning, testing and internationalization standards

Planning- analyze data formats and validation rules

Data cleaning- Ensure data is clean and complete

Testing- Identify any issues become full migration

Internationalization standards- Use international standards for data formats to minimise compatiblity problems

Gamma testing

Testing of software that is ready for release or close. Can happen when big changes occur after beta testing. Focuses on product readiness

Types of testing

Alpha

Beta

Gamma

Feedback collection

Iterative improvement

User acceptance testing (UAT)

Outline 3 main styles of user documentation

Tutorial- Step by step practical exercises, good for new users needing guided practice

Thematic- Chapter/section based and systematically covering each feature, Good for users learning system feature by feature

List/reference- Concise lists for quick lookup of commands, good for technical or experienced users needing fast answers

Methods of providing user documentation

Printed/PDF/ online manuals

Help files

FaQs

Live chat/video support

Pros and cons of Manuals and Help files in providing user documentation

Manuals:
Pros- Can be detailed, structured and printable. PDFs and web pages are easy to distribute

Cons- May become outdated, long manuals can be hard to search or intimidating

Help files:
Pros- Contextual help exactly where needed inside interface

Cons- May be brief or limited, not a full replacement

Pros and cons of FaQs and Live chat/video support in providing user documentation

FAQs:
Pros- Provide quick answers to common questions, accessible anytime.
Cons- May not cover all issues, can lack depth.

Live chat/video support:
Pros- Offers real-time assistance, personalized help for complex problems, human interaction.
Cons- May require waiting time, not always available.

Self instruction pros and cons

Pros- Users learn whenever needed through manuals, videos etc supporting just in time learning. Saves cost on instructors, venues and time away from work.

Cons- Success depends on user motivation and ability to learn independently, Lack of access or poorly designed training materials reduces effectiveness

Formal classes pros and cons

Pros- Real time interaction with instructor and peers, immediate feedback and questions, environment structured and focused on learning

Cons- Shy users may participate less, dominant personalities hinder inclusivity, instructor has limited time per individual

Common causes of data loss

• Accidental deletion- backups

• Computer viruses/malware

• Physical damage

• Continued use after warnings

• Power failure - use UPS

• Firmware corruption

• Natural disasters

Order of release strategies and what they are

1. Pre alpha- Very early internal build lacking features, only for developers

2. Alpha- Most main features added but quite buggy, tested within organisation

3. Beta- Feature complete and tested by external users

4. Release candidate- Almost ready for release, no new features only bug fixes

5. General availability- Stable public version for everyday use, later changes are patches/updates

Update strategies

• Automatic

• Manual

• Scheduled

• Phased/gradual rollout

Outline Pros and cons for automatic vs manual updates

Automatic:

Pros- Software installs updates itself making it effortless, updates improve security and compatibility

Cons- Needs internet, can install at bad times or c

Manual:

Pros- User controls which updates are installed and when, can avoid interruptions.

Cons- Forgetting or ignoring updates can miss improtant security or bug fixes, may not know how to update

Outline Pros and cons for scheduled vs phased updates

Scheduled:
Pros- Install at planned times reducing disruption

Cons- Delays urgent patches, if schedule fails users may be stuck on older versions for longer

Phased:
Pros- Limits impact of bad updates by testing on small groups, easier rollback if problems appear

Cons- Different users on diff versions at same time, hindering support and compatibility

Outline 3 reasons why updates matter

Important due to:

• Performance issues- Not updating can cause slower programs, higher cpu use, crashes and instability

• Security vulnerabilities- Regular updates patch known security gaps, reducing the risk of exploits and malware

• Compatibility- Updates ensure software works seamlessly with new features, operating systems, and hardware.

How to mitigate issues through change management?

Planning and communication- Clear explanations for changes, how they will be done and a timeline for implementation of new system keeping all involved informed reducing uncertainty

Training and support- Providing helpful resources like tutorials helps users adapt minimizing frustration and ensuring optimal use of new features

Risk management- Identify potential problems that may arise during change and developing stages to avoid them.

Factors to consider for successful change management

People- how change impacts diff user groups, address concerns and provide appropriate support

Technology- Ensure compatibility of existing infrastructure and data with new system through thorough testing

Processes- Update documentation and procedures to reflect changes made

Business mergers and compatibility and example

When business merge, existing computer systems need to be compatible in order to allow for transfer of data and smooth operating
Example- Two different companies may use similar but different ID fields or variables to store the core values meaning that reformatting would be required to merge the data.

International interactions and compatibility

When organizations collaborate internationally, issues from differences in the following can arise:
Software- one company might use software incompatible with the others systems

Languages- Software interfaces and data might be in different languages

Social and ethical considerations in compatiblity

Accessibility- if a new system isnt compatible iwth assistie tech, its not inclusive towards those with disabilities

Data privacy- Merging data from different systems raises user privacy and data protection concerns.

Hardware

Physical parts of a computer system, including internal components like CPU and RAM, and external devices like monitors and keyboards

Software

A set of programs ,instructions, or data that directs computer operation and allows it to execute specific tasks

Types of software

• System software

• Application software

• Utility software

Difference between system, application and utility softwares

System- Includes operating systems that manage hardware and provide a platform for application

Application- Programs designed for specific tasks, such as word processors, web browsers and games

Utility- Tools that perform maintenance tasks, like antivirus and disk cleaner

Peripherals

An external device connected to a computer that adds functionality, such as input, out or both

4 types of peripheral devices

• Input- Allows users to enter data (keyboard)

• Output- Display or produce results (monitor)

• Storage- External drives and USB flash drives

• Communication- Network cards and modems

Definition of network

A system where multiple computer or devices (nodes) are connected to share data, resources and communicate with each other.

They enable:

• communication

• resource sharing

• collaboration between users and devices

Human resources

The people who work within an organisation, involved in design, development, operation and maintenance of computer systems

Examples- System analysts, programmers, network administrators, technical support, end users

Interactions between system components

Hardware and software- Software runs on hardware, and hardware relies on software for instructions

Peripherals and hardware- Peripherals extend hardware capabilities enabling input, output and storage

Network and Software- Networks allow software applications to communicate and share data across devices

Human resources and systems- People design, implement and maintain systems, ensuring they meet user needs and organisational goals

Roles of computers

1. Client

2. Server

a. Email server

b. DNS server

3. Router

4. Firewall

Difference between client and server roles

Client- Enables user interaction with networked services

Server- Provides resources and services to multiple clients, email serves for reliable email communication and DNS for simple access to online resources

Difference between router and firewall roles

Router- Connects networks and directs data efficiently

Firewall- Protects networks from unauthorized access and threats

Routers manage data traffic between networks, while firewalls filter incoming and outgoing traffic to prevent unauthorized access.

What is a client and how they work

A computer or device that requests services or resources from a server

Clients are typically user facing and rely on servers to provide data and processing power. Client send requests to servers and receive responses, enabling users to access websites, emails and other services.

What is a server

A device or program that provides services or resources to client, can be dedicated machines or software applications.

Types of server

Web server- Hosts websites and serves web pages to clients

Database serve- Manages and provides access to databases

File server- Stores and shares files across a network

Key functions of email servers

SMTP- Sends outgoing emails

IMAP- Retrieves incoming emails or clients

DNS

A type of server that translates human readable domain names into ip addresses that computers use to identify each other on the network

Router

Devices that direct data packets between networks. They determine the optimal path for data transmission using routing protocols and routing tables

Firewall

Security device that monitors and controls network traffic based on predetermined rules. Act as a barrier between trusted and untrusted networks.

Client-Server module

Network architecture where clients request services and servers provide them

Client-Server module example

A web browser (client) requests a web page from a web server, which processes the request and sends the page back to the browser

why the need for 2 (SMTP and IMAP) different protocols in email servers

Because sending data and retrieving data require different logical processes and interactions between the client and server

Implications of privacy breaches

Identity theft- Unauthorized access to personal data can lead to financial and reputational damage

Surveillance- Monitoring of individuals or groups using technology, often without their knowledge or consent

Ethical considerations when working with surveillance

Transparency- Organisations should disclose what data is collected and how it is used

Content- Users should have the option to opt in our out of data collection.

Digital divide

The gap between individuals, groups or countries in terms of access to digital tech such as the internet.

Software license and diff types

A legal agreement that defines how you can use, share or modify a piece of software

Proprietary license - Cant modify or share software (microsoft office)

Open source license- You can view change and share the code (linux)

Freeware- Free to use but usually not editable (skype)

Shareware- Free trial then you pay to use

Globalisation

The interconnectedness of the world through technology, enabling the rapid spread of information and ideas

Positives and negatives of globalisation

+Increased communication and Access to information

- Cultural homogenization: Dominant cultures overshadow others

- Digital colonialism: The imposition of tech and values by powerful countries on less developed ones

3 Ways to improve ethical design of systems

1. Reliability- Ensuring systems function correctly to prevent data loss or harm

2. Integrity- Protecting the accuracy and completeness of data

3. Authenticity- Verifying the identity of users to prevent unauthorized access

Stakeholders

People or groups who are affected or interested in a new system. This includes users, clients, developers, managers and investors.

Stakeholder categories

• Ends users

• Developers

• System administrators

• Business leaders

Role of End users and developers as stakeholders

End users- Provide insight into usability and functionality and areas for improvement

Developers- Translate requirements into technical solutions and ensure system is feasible and scalable

Difference in roles of system administrators and business leaders as stakeholders

System admin- focus on security, reliability, maintenance and plan for system updates

Business leaders- Align system with strategic objectives and ensure project is cost effective and delivers value

What is a prototype

Preliminary version of a system or product, designed to demonstrate, its core features and functionality

Types of prototypes

Low fidelity- Quick, inexpensive (paper sketches), focus on functionality

Mid fidelity- Interactive mockups, more detailed

High fidelity- Resemble final product, made with prototyping tools and for advanced testing

Why is prototyping important?

• Visualizing ideas

• Facilitating feedback

• Identifying issues

• Validating assumptions

• Clarifying ambiguities

• Encouraging collaboration

What is iteration

The repetition of a set of instructions or processes until a desired outcome is achieved