Analysing a System (Flow Charts and Flow Diagrams)

When analysing a system the analyst after finishing the stsge of information collection and then selecting the output and input methods he reaches to a stage of Recording information about the system.In this stage the analyst can use data flow and data diagram charts to make this stage easier.
And in this post am gonna write about about the system data flow diagram and the others...

1- Program flow charts

Program flow charts 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. The basic ones include:

2- System Flow charts

A system flow chart is used to show how data in a computer system is processed. It does not involve the complex detail of the porgram instructions(which are represented by the porgram flow charts) but it gives a broad view of the system operation.

Example :

Data Flow Diagrams:

Data Flow Diagram (DFD) is an important technique for modeling a system’s high-level detail by showing how input data is transformed to output results through a sequence of functional transformations. DFDs reveal relationships among and between the various components in a program or system.
DFDs consists of four major components: entities, processes, data stores and data flows.

Example :

Process flow diagram :

A process flow diagram (PFD) is a diagram commonly used in engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between major equipment of a plant facility and does not show minor details such as piping details and designations. Another commonly-used term for a PFD is a flowsheet. Typically, process flow diagrams of a single unit process will include the following:

Process piping
Major bypass and recirculation lines
Major equipment symbols, names and identification numbers
Flow directions
Control loops that affect operation of the system
Interconnection with other systems
System ratings and operational values as minimum, normal and maximum flow, temperature and pressure
Composition of fluids

Example :

THE END....