learning aim b

• a hacker is a person who gains unauthorised access to a computer system
• a hacker who misuses computers is a black hat hacker
• Information and data flow diagrams

  Used by organisations to explain systems, data and information
• Interpret information presented in data flow or information flow diagrams

  1. Understand how to interpret

  2. Be able to interpret
• Draw data flow or information flow diagrams

  1. Represent a given scenario

  2. Draw a diagram
• Forms of information

  • Written descriptions
  • Tables
  • Charts
  • Diagrams
  • Storyboards
  • Infographics
  • Dashboards
• Information flow diagrams (IFDs)

  • Show how information flows through a system or organisation
  • Include people/users of the system
  • Show how information flows between organisations and within an organisation
• How to create information flow diagrams

  1. Use squares for key parts of the system such as people or departments

  2. Use arrows to show how the information flows around the system

  3. Label the arrows with what information is being transferred
• Data flow diagrams

  1. Show who or where the input data comes from

  2. Show how data flows around the system

  3. Show how the data is processed

  4. Show what data is stored

  5. Show who or where data from the system is output to
• Symbols used in data flow diagrams

  • A person, organisation or another system which sends or receives information
  • A process or function, sometimes but not necessarily numbered
  • A file or database
  • Data or information flow shown by the direction of the arrow
• A simple data flow diagram in a fast food restaurant

  • Customers use a touch screen to place their order
  • The amount to pay is displayed on the screen
  • The order is sent to the kitchen
• Process and entities in a data flow diagram

  • Identify the process
  • Identify the entities
• Fast food ordering system

  • Orders will be stored in an Order file (process, data store)
  • Quantities ordered will be subtracted from a Stock file (process, data store)
  • Reports will be generated from the Order and Stock files and sent to the manager (process, two data stores, entity)
  • The manager will order new stock from the supplier (entity, process, entity)
  • The quantities will be updated in the Stock file (process, data store)
• Data flow between entities

  • Data flows always go to, or come from, a process
  • Never draw a data flow line between two entities
• Process box requirements

  Needs at least one input and at least one output
• Data flow from external entity to data store

  Do not draw a data flow from an external entity directly to or from a data store
• Numbering process boxes and data stores

  • May be useful to refer to the processes
  • Data stores can also be numbered. D can also be used for a digital store and M for a manual store
• Information flow diagram (IFD)

  • Shows users/people involved in a system
  • Shows how information flows around the system
• Symbols used in an IFD

  Squares and arrows
• Data flow diagram (DFD)

  • Shows the entities (people, users and other systems)
  • Shows data flow within a system
  • Shows the processes to the data that take place
  • Shows the data stores (files or databases) used in the system
• Symbols used in a DFD

  Entity, process, data store, data flow
• Flowchart

  A way to present the steps required in a clear manner, easy to understand and less likely to be misunderstood than a list of text
• Morning routine

  1. If it's the weekend sleep for another two hours

  2. Otherwise, take off duvet

  3. Go to bathroom

  4. Have shower

  5. Brush teeth

  6. If it's a school day find school uniform

  7. Get dressed
• Flowcharts

  • They are a clearer way to present the steps required
  • They are easy to understand
  • They are less likely to be misunderstood than a list of text
• Completing a flowchart

  1. Brush teeth

  2. If it's a school day find school uniform

  3. Get dressed

  4. Have breakfast
• Flowchart symbols

  • Start
  • Input/Output
  • Process or calculation
  • Decision
• Flowchart symbols

  • Input phone number
  • Add 10 points to the score
  • Tax = income * 20%
  • Display total tax due
• Flowchart symbols

  • Start
  • Input/Output
  • Process/Calculation
  • Decision
• According to the flowchart

  When can you pick up food you have dropped?
• Companies will often create flowcharts to show what to do when a problem occurs, such as: fire procedures, customer complaints, manufacturing defects
• Companies may also have procedures to help employees to do their day to day work
• Variables

  • Allow us to store a number or text in a flowchart
  • Are often used in calculations
  • Calculations will always be in a process box
  • You can input or output what is stored in the variable
• Flowchart finding how much a student will spend on food and drink each week

  1. total = 0

  2. count = 0

  3. count = count + 1

  4. total = total + count
• The statement count = count + 1

  Means "Add 1 to the variable called count"
• What will be output from this flowchart?
• Flowcharts are a form of notation used to express the steps in an activity
• Flowchart symbols

  • Start / End
  • Input / Output
  • Process
  • Decision
• Situations where a company may want to use a flowchart

  • To show what to do when a problem occurs (e.g. fire procedures, customer complaints, manufacturing defects)
  • To help employees do their day-to-day work
• Computer system


  All the hardware and software required to perform the required tasks
• Components of a simple computer system

  • Input
  • Processing
  • Output