Please enable JavaScript.

Coggle requires JavaScript to display documents.

System Fundamentals - Coggle Diagram

- - - - Regular backup of files using hard disks or magnetic tapes
      - Firewall installation
      - Data storage in multiple locations
      - Removed hard copies – make them digital to prevent from damage
      - Installation of Antivirus programs
      - Failsafes
      - Online auto-saving backups
      - Redundancy: Duplication of storage devices and stored data to secure the stored data (failsafe method)
      - Removable media: Quick permanent data backup and data storage solutions – diskettes, blu-ray discs, CDs, DVDs, USB.
      - Failover: Computer system on standby capable of switching as a spare upon hardware, software, or network failure that might be encountered by the primary server. (automatic)
      - Switchover: The primary and secondary server interchange primary roles.
  - - - Internal documentation: Code comprehension features and details provided as part of source code (NOTE: IMPOSSIBLE TO BE READ AND FULLY UNDERSTOOD BY FINAL USER)
        
        Appropriate module headers
        
        Appropriate comments
        
        Useful and meaningful variable names
        
        Useful module, classes, methods and function headers
        
        Appropriate code indentation
        
        Appropriate code structuring
        
        Appropriate use of enumerated types
        
        Appropriate use of constant identifiers
        
        Appropriate use of data types defined by the user
      - External documentation: Written as separate document from source code (users’ guide, software requirement specs, design description and implementation features of the program and test document).
    - - Manuals
      - Email support: Asynchronous type of support and can be provided via an email address – users contact the support team of the company to help resolve any technical problems.
      - Embedded assistance or integrated user assistance: Inbuilt help systems – e.g. MS Office suite (tool tips and dynamic page content within the system itself)
      - Frequently asked questions (FAQ): Listed questions and answers to give users answers to common set of problems and pertaining particular topic.
      - Live chat sessions: Real time support extremely useful for emergency situations – live chat technician will ask for the description of the problem and try to give a solution to the problem.
      - Online portals: Online support is provided in many ways depending on the product or service being documented – it may provide updated manuals, supported pages, and FAQ pages.
      - Remote desktop connections: Function that enables a specialised person to connect to the user’s PC across the internet – this connection allows specialised technicians to take control of the user’s PC.
    - - Self-instruction or self-study: Allows user to learn on his/her own until he/she achieves mastery of the subject. Printed manuals, books, e-books or other resources such as video tutorials or online exercises can be provided and used whenever the user needs to improve their skills. Disadvantage: lack of guidance or teacher support and final results are completely dependent on the user’s motivation and ability to learn.
      - Formal classes: Interactive setting that promotes open and free discussion between students and teachers (instructors). Direct interaction allows for ideas to be easily exchanged without any technical communication barriers. Disadvantage: Shy members may feel overwhelmed by more confident students in the class.
      - Online/remote training: Allows participants to take part in high quality training from anywhere in the world and all of its contents is accessible 24/7. Disadvantage: Lack of the required infrastructure will make students ineligible for the course, students and instructors must posses minimum IT skills, places grater responsibilities and control on students – not effective for dependent and immature learners.
  - - - Organisational issues that should be anticipated
        
        Lack of guiding organisational and business strategies
        
        Lack of stakeholder and end-user participation
        
        Lack of end-user ‘ownership; of system
        
        Lack of attention to required training
        
        Lack of attention to various organisational issues, such as organisational culture
        
        Lack of attention to the design of tasks and jobs, allocation of information system tasks, and the overall usability of the system.
      - A proposed project of system installation should always keep in mind different aspect of its feasibility
        
        Technical feasibility
        
        Economic feasibility
        
        Legal feasibility
        
        Operational feasibility
        
        Schedule feasibility
    - - Change management involves various parameters and is a process of shifting individuals, teams, departments, and organisations to a desired state.
      - A change management is successful when all the stakeholders accept and embrace the change in their working environments with a goal to maximise benefits and minimise the negative impact of change on individuals.
    - - Legacy system: Old technology, hardware, computer system, or application program.
        Business merger: Combination of 2 or more business entities to reduce costs.
      - 4 Strategies for integration:
        
        Keep both information systems, and develop them to have the same functionality. (High maintenance cost)
        
        Replace both information systems with a new one (increased initial cost)
        
        Select the best information system from each company and combine them. (Difficult for employees to operate another company’s information system.
      - Software incompatibility: A situation where different software entities or systems cannot operate satisfactorily, cooperatively or independently, on the same computer, or on different computers liked by a local or wide area computer network.
    - - Locally hosted system:
        For larger and complex systems (high initial cost and maintenance)
      - Remotely hosted system:
        A solution when the administration wishes to outsource responsibilities for maintenance, support, backups, security, etc.
      - SaaS (Software-as-a-Service) or “on demand software”:
        Contemporary delivery method that allows software and date to be hosted and managed centrallh on a remote datacentre.
        
        PROS
        
        Has a low initial cost
        
        Requires few investments in installation, maintenance, and upgrading
        
        Only required to pay SaaS subscription (cheaper in short to medium term)
        
        Only a web browser and internet connection required to access SaaS applications
        
        Considered a safe solution because applications and data reside in the cloud service of the provider.
        
        CONS
        
        Performance of a web-browser based application hosted remotely is low compared to software running on a local server.
        
        SaaS integration with other SaaS solutions or software installed locally is always difficult.
        
        Risk of dataloss
        
        Does not have the best security as data is not locally protected.
    - - Types of changeovers
        
        Parallel: Both systems work in parallel in a short time, once the new syste, is proven to be functioning properly, the old system can be terminated. (Requires alot of maintenance cost to sustain both systems and is also inefficient).
        
        Big Bang or Direct: Terminating an old system directly as the new system is being implemented. (Prefered method only when the system is not critical because it is something very risky to do)
        
        Pilot: New system will be introduced in one of the sites, if it is proven to be working and well-accepted, the rest of the sites will also update to the new system one at a time. (low risk and pilot sites can observe as models.
        
        Phased: Company concerts one module of the system at a time – different parts of the organisation converted at different times. (Extended training period as the phases of implementation are separately done per module, per department, etc).
    - - Steps of data migration
      - Three stages of data migration
    - - Different ways and phases of testing
        
        Functional testing: Tests individual commands, text input, menu functions, etc. It confirms that they perform and function correctly according to the design specifications.
        
        Data testing: when a normal, abnormal, and extreme data is put into the system. Example case: There is a program that accepts a student’s percentage in a math exam and gives a “pass: message if the number entered is ≥60; otherwise it prints a “fail” message. Program can be tested with:
        
        Normal data: 76 will be used to check if “pass and “fail” messages are appropriately provided
        
        Data at the limits should be used, in this particular case (0, 59, 60, 100) are all examples of normal data at the limits.
        
        Extreme data: Data that will be outside the normal limits previously set. These kinds of data will be rejected during validation testing.
        
        Abnormal/illegal data: Type of data that is not supposed to be there in a particular program – these data can be in the form of a string, character, not an integer, or mistyped integers.
        
        Alpha testing: Done before the software product is made available to the general public (usually done within the company that develops the software)
        
        Beta testing: Testing that involves other end-users outside the company. This is the stage where users get to give comments and suggestions (feedback). These feedbacks are useful to fix defects and errors that were missed as well as make last minute changes for improvements.
        
        Dry-run testing: Conducted using pen and peper by the programmer (algorithm examined and ran mentally by the programmer)
        
        Unit and integration testing:
        
        Individual testing: Individual parts of the system individually tested.
        
        Integration testing: Entire system tested at the same time to verify that components can run together.
        
        User acceptance testing: Used to determine if the system satisfies the customer needs and demands – last stage of software testing process.
        
        Debugging: Finding and correcting errors (bugs) in the system.
      - Validation in relation to data input:
        
        Validation: Process of evaluating whether data input follows appropriate specifications and is within limits.
        
        Verification: Process of ensuring that the data input is the same as the original source data (data verification ensured through double entry).
      - Questions for Verification vs Validation in software testing
        Verification – confirmation that a computer product meets identified specs
        Validation – confirmation that a computer is appropriate for its intended use.
        
        Validation: Are we developing the correct system?
        
        Verification Are developing the system correctly?
        
        Validation: Does the product meet the customer-need?
        
        Verification: Does the product comply with a specific regulation or condition?
  - - - Patches (SMALLEST ALTERATION)
      - Upgrades
      - Updates
      - Releases (LARGEST ALTERATION)
- - - - Computer hardware: The physical elements of a computer, e.g. screen, CPU, etc.
      - Software: A series of instructions that can be understood by a CPU – instructions guide the CPU to perform different operations.
      - Peripheral devices: Auxiliary device that can communicate and work with a computer which extends the capabilities of the computer system it is connected to (printers, mouse, keyboards, input/output devices, etc).
      - Computer network: Set of computer systems that are interconnected and share resources, as well as data.
      - Human resources: People who are used or could be used in an organisation, business, or economy.
    - - Dumb terminal
      - Thin client
      - Client
      - Email server
      - Router
      - Domain Name System (DNS) Server
      - Firewall
      - Client-server
    - - Reliability: Refers to how well an IT system functions. Computer failures causes data loss, time loss, money loss, injury or even death – reliability the value of a system.
      - Integrity: Completeness and accuracy of data. Data lacks integrity if it is incomplete, out of date, or has been purposely or unintentionally altered.
      - Inconsistency: Problems that may arise when only 1 copy of a duplicated information is updated in a database causes inconsistency.
      - Security: Protection of a system from unauthorized access through authentication (person proving their identity to gain identity). Some common security systems include biometrics, proprietary tokens, passwords, firewalls, and locks.
      - Privacy: The ability to control how and to what data is used and shared to others.
      - Anonymity: Privacy may become anonymity when an individual uses an IT system to conceal their true identity. Anonymity becomes an issue in IT when someone conceals their identity to commit cybercrimes.
      - Intellectual property: Refers to ideas, discoveries, scientific endeavours, photographs, films, essays, and art works. The laws to protect intellectual property are called copyright laws. However, in the modern world, it is easy to break copyright laws due to ‘copy and pasting’ and illegal file sharing practices.
      - Digital divide and equality of access: The growth and applications of IT systems are unequally distributed across all parts of the world. Factors such as the lack access to IT infrastructures and online services, economic costs, lack of literacy, and lack of basic resources such as electricity becomes the reason that digital divide exists in the world.
      - Surveillance: Involves using IT to monitor individuals or groups of people with or without their consent. To some extent, the lack of privacy is the main reason this is an issue because government systems are filled with surveillance systems.
      - Globalisation and cultural diversity: Traditional cultures and values may diminish gradually because IT diminishes the importance of geographical, political, economic, and political boundaries worldwide throught the fast spread of information.
      - IT policies: Procedures that promotes the appropriate use of IT systems. However, the fast-paced progression of IT can quickly make policies easily change and old ones obsolete.
      - Standards and protocols: Predefined technical rules and conventions that developers of hardware and software should always follow – not following the standards and protocols may cause major incompatibility issues.
      - PROS AND CONS OF IT SYSTEMS
  - - - End-user
      - Manager/supervisor
      - Specialists
    - - Interviewing stakeholders
        
        Structured interviews
        
        Unstructured interviews
      - Questionnaires
        
        Closed or restricted
        
        Open or unrestricted
      - Direct observation of current procedures
    - - Examining current system
      - Literature search
      - Examining competing products
      - Analysis of organisational capabilities: Sense-making, decision-making, asset availability, and operations managemen are associated with the effective implementation of an information system, which in turn positively affects organisational performance. IT systems in modern companies can provide a gain in competitive advantage if they are planned to:
        
        Increase client trust
        
        Perserve brand strength
        
        Perserve organisation reputation
        
        Maintin corporate resiliency
        
        Enhance organisational piece
    - - Different types of processing
      - System flowcharts: Refers to the description of a data processing system, including the flow of data through any individual programs involved, but excluding the details of such programs. These are frequently constructed during analysis activities and represent various computer programs, files, databases, associated manual processes, etc – the only way to refer to hardware. Symbols used in flowchart designs:
      - Data Flow Diagrams (DFD): Shows how data moves through a system and the data stores that the system uses. It does not specify the type od the data storage and the type of data. Symbols used in DFDs:
      - Structure charts: Describes functions and subfunctions of a system as well as the relationships between modules of a computer program. Example of a structure chart:
      - Modular design: Process of designing system modules individually and then combining the modules to form a solution to an overall problem. Terms related to modular design:
        
        Top-down design or “stepwise refinement”: Partition of a problem into smaller sub-problems.
        
        Pseudocode: Artificial language that is not directly related to any particular hardware and is used to describe algorithms.
        
        Module: Complete and independent part of a program or an algorithm.
        
        Modular programming or “modularity”: Method of partitioning a computer program into separate sub-programs. Each sub-programs can be easily modified and maintained without having to alter other sub-programs.
        
        Modular language: Language that supports modular programming.
    - - Attracts attention of client
      - Provides enough concept for investors to decide whether they want to fund production or not
      - Encourages active participation between users and developers
      - Gives an idea of the final product
      - Indentify problems with the efficiency or the design
      - Increases system development speed
  - - - Accessibility: The potential of a service, product, device or environment to serve and meet the needs of as many individuals as possible. Accessibility can also be related to the use of various assistive technologies for disabled people.
      - Usability: Potential of a product, application or website to accomplish user goals – it relates to the effectiveness, efficiency, and satisfaction of use.
      - Ergonomics: Design of safe and comfortable products, systems or processes, specifically for people.
    - - Complexity/simplicity: Amount of effort for a solution or great result.
      - Effectiveness: Comparison of user performance against a predefined level.
      - Efficiency: Task completion time after the initial adjusting period.
      - Error: Number of errors, type of errors and time needed to recover from it.
      - Learnability: Time used to accomplish tasks on first attempt.
      - Memorability: Time, number of button clicks, and steps by users when they return to the device after not using it for some time.
      - Readability/Comprehensibility: Reading speed
      - Satisfaction: Whether users like it or not
    - - Visual impairment (blindness to colour deficiency)
        
        Output methods and devices: Speech output devices that can read the screen text, braille displays that allows braille characters to be displayed using pins.
        
        Output methods and devices: Speech output devices that can read the screen text, braille displays that allows braille characters to be displayed using pins.
      - Hearing and speech impairments
        
        Output methods and devices: Replace sound signals with visual effects (i.e. using subtitles).
      - Cognitive problems and learning disabilities
        
        Input and output methods and devices: Software that provides active participation, multi-sensory experiences, strong interaction, positive reinforcement, personalised instruction, individualised instruction, and repetition that can be useful in skill building.
      - Mobility impairments, limited hand mobility, or Parkinson disease (INPUT METHODS AND DEVICES)
        
        Disk guides for CDs, DVDs, diskettes
        
        Pointing device, mouth and head-sticks to replace keyboard
        
        Left-handed or right-handed keyboards
        
        Trackballs and specialised input devices as wearable computer interfaces to replace mouse and keyboard
        
        Large expanded keyboards
        
        Scanning and mose code input
        
        Special knobs relying on specific muscle actions
        
        Sip-and-puff that can be controlled by inhaling and exhaling air through a tube
        
        Natural language processing – interact with PC by speaking or spelling words
        
        Word prediction software for mobility impaired individuals
      - Range of usability problems that can occur in a system
        
        Ticketing systems
        
        Complexity/simplicity: Unclear instructions on how to obtain a ticket; lack of built-in help
        
        Effectiveness: Not abiding to international standards
        
        Efficiency: Complicated site that makes users perform unnecessary actions
        
        Error: User books more tickets than wished so have to restart the booking process
        
        Learnability: Users gets confused when first entering the site
        
        Memorability: Users gets confused and takes time to remember the procedure
        
        Readability/Comprehensibility: Font and background selected not appropriate
        
        Satisfaction: Customers unsatisfied with the poor system
        
        Online payroll systems
        
        Complexity/simplicity: Unclear instructions on how to calculate taxes; lack of built-in help
        
        Effectiveness: System is designed for another country, competing systems may already be localised
        
        Efficiency: User unsuitable for users’ needs because many modifications are required to be performed upon every use
        
        Error: No verification or validation rules; prone to errors
        
        Learnability: Design of menus is not straightforward
        
        Memorability: Unintuitive interface
        
        Readability/Comprehensibility: Hard-to-read interface
        
        Satisfaction: Difficult to use, unhappy users
        
        Scheduling systems
        
        Complexity/simplicity: Unclear instructions on how to use the system
        
        Effectiveness: Other applications can sync better
        
        Efficiency: Difficult to understand making a simple task
        
        Error: Wrong appointment entries for rescheduling
        
        Learnability: Complex menus
        
        Memorability: Difficult to remember the optimal way to add a task
        
        Readability/Comprehensibility: Very small characters
        
        Satisfaction: Ideal for another country with different time unit format
        
        Voice recognition systems
        
        Complexity/simplicity: Lack of built-in help
        
        Effectiveness: Competition produces better results
        
        Efficiency: Poor word-recognition performance
        
        Error: Prone to errors
        
        Learnability: Takes time for the software to recognise the voice of a new user
        
        Memorability: Software needs retraining
        
        Satisfaction: User needs to speak loudly which is embarrassing in public
        
        System that provide feedback
        
        Complexity/simplicity: Lack of intuitive interface, no native language support, difficult to obtain feedback
        
        Effectiveness: Gives incorrect/irrelevant feedback
        
        Efficiency: Feedbacks can’t be used by user and they are given rarely
        
        Error: Difficult to re-enter information after a wrong input
        
        Learnability: Difficult to learn
        
        Memorability: Difficult to remember
        
        Readability/Comprehensibility: Difficult to read the instructions
        
        Satisfaction: Inconvenient user interface
      - Moral, ethical, social, economic, and environmental implications of the interaction between humans and machines
        
        Artificial intelligence (AI) and robotics: 2 computer science fields that leads to a different future where computers will achieve its own kind of intelligence. Many scientists are concerned that advances in AI might lead to unpredictable and dangerous situations when there is no human control over them.
        
        Manipulation of sound, picture, or video: Technological advancements may be used to fool people’s senses into an experience that has never happened before.
        
        Printed-paper waste: Advancements in printing technology increases the amount of paper wastes disposed everyday, even recycling paper requires alot of chemical and energy to do.
        
        Electronic waste: Advancement in technology increases electronic waste that contains lead, cadmium, mercury, chromium, PVC, and other dangerous chemicals that end up in landfills causing pollutions.
        
        Digital divide: Exists only between high and low income households, digital divide may cause increasing inequalities and reduced opportunities for education, entertainment, and income.