CSC - Documentation

Documentation is essential for any information system and / or product
Some documentation helps developers and designers to understand the ins and outs of the system or project, as well as a an integral part of planning
Other documentation is created specifically to help the end-user operate the system

A system context diagram, or context diagram, is a diagram used to show the high-level processes of a system
These processes are shown along with how they interact with external entities
Data is shown as to be "flowing" between the system and external entities, as depicted with arrows
Context diagrams are a step before Level-0 DFDs (data flow diagrams) and use similar symbols
- A process is represented with a circle
- An external entity is represented with a rectangle
- A data store is represented with two parallel lines
- A data flow is represented with a straight line and arrow head in the direction of the flow
Context diagrams only show essential general processes without breaking down each step

A data flow diagram is also known as a DFD
It's the next level up from a context diagram, where we look at each process and break it up further in easy-to-read data flows
These data flows are how the system interacts with external entities, as well as databases
The processes are numbered with decimals, meaning the first process will have sub-processes in a DFD numbered as "1.1", "1.2" etc.
Data flow diagrams use the same symbols as a context diagram
Refer to the section "For you to do" below, number 2, for more on DFDs.

Source: http://flylib.com/books/en/2.148.1.49/1/

System manuals can also be referred to as internal documentation
Internal documentation refers to notes and instructions within projects, often seen only by developers
This includes comments within the source codes of a project
System manuals are generally created for developers and people within the project

User manuals can also be referred to as external documentation
External documentation is any form of manual or guide used to instruct the end-user of a system
User manuals are generally created for end-users in order to educate them on how to use the system

1. What does DFD stand for? What is the purpose of a DFD?

2. How is a process represented? Does it start with a verb or noun?

3. How is an external entity represented? Does it start with a verb or noun?

4. What is an entity?

5. How is a data store represented? What is it?

6. What is a context diagram?

7. What does a data flow look like?

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System Development Documentation