IB Computer Science - 1.2.7 Illustrate system requirements

IB Computer Science

1.2.7 Illustrate system requirements

Assessment Statement/s

1.2.7 Construct suitable representations to illustrate system requirements

Commonly used Flowchart Symbols

Commonly used symbols to represent basic input--> process-->output

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Systems flowchart

System flowcharts are a way of displaying how data flows in a system and how decisions are made to control events. To illustrate this, symbols are used. They are connected together to show what happens to data and where it goes.

A system flowchart symbolically shows how data flows throughout a system and how event-controlling decisions are made.

For instance, this template shows the flow for logging into an online service.

Algorithm Flowchart

As perhaps the most flexible type of diagram, flowcharts can be used to show algorithms, including computer algorithms, in an easy-to-digest visual format.

Entity Relationship Diagram

An ER diagram helps to illustrate the relationships between entities stored in a database. This ER diagram example visually communicates information on hockey teams and games and how they relate within a database.

Data Flow Diagram (DFD)

A data flow diagram (DFD) shows how information flows through an information system, including inputs, outputs, where data is stored, and where it travels. For instance, this DFD example shows how information flows through a system for receiving and filling orders at a bookstore.

DFD Level 0

A level 0 data flow diagram (DFD), also known as a context diagram, shows a data system as a whole and emphasizes the way it interacts with external entities. This DFD level 0 example shows how such a system might function within a typical retail business.

DFD Level 1

A level 1 data flow diagram (DFD) is more detailed than a level 0 DFD but not as detailed as a level 2 DFD. It breaks down the main processes into subprocesses that can then be analyzed and improved on a more intimate level.

DFD Level 2

A level 2 data flow diagram (DFD) offers a more detailed look at the processes that make up an information system than a level 1 DFD does. It can be used to plan or record the specific makeup of a system.

Steps to design a system flowchart

1. Identify and list inputs, including hardware.
2. Identify and list processes.
3. Identify and list storage, including hardware.
4. Identify and list outputs, including hardware.
5. Add the appropriate input symbols to the top of the diagram.
6. Add the appropriate storage symbols to one side of the diagram.
7. Add the appropriate process symbols to the middle of the diagram.
8. Add the appropriate output symbols to the bottom of the diagram.
9. Analyze the system and add the data flow lines from inputs to processes.
10. Analyze the system and add the data flow lines between processes and storage.
11. Add the appropriate data flow lines between processes and outputs.

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