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Write short notes on : a. Data store b. Actors c. Control flow
a. Data Store:
- Definition: A data store is like a storage unit in a data flow diagram, holding data for future use.
- Function: It doesn’t perform actions but responds to requests for storing and retrieving data.
- Flexibility: Allows accessing values in a different order than generated.
- Representation: Shown as parallel lines with the store’s name in between.
- Arrows: Input arrows indicate operations modifying data, while output arrows show retrieved information.
b. Actors:
- Definition: An actor is an active participant generating or consuming values in the data flow.
- Attachment: Actors connect to the inputs and outputs of a data flow diagram.
- Examples: Users, thermostats, or computer-controlled motors can be actors.
- Representation: Drawn as rectangles, denoting them as objects. Arrows indicate inputs and outputs.
c. Control Flow:
- Role: It helps show which paths are executed and in what order in a data flow diagram.
- Inclusion: Control flows are added to illustrate Boolean values affecting process evaluation.
- Nature: A control flow is a yes/no factor, not an input value to the process.
- Representation: Displayed as dotted lines from a process producing a Boolean value to the controlled process.