Software Engineering - Introduction to System Engineering

There are various kinds of systems in technological field which are known as operating system, salary management system, library system, payment or billing system and many more.

A system is purposeful collection of interrelated components that work together to achieve some objectives

Software Engineering

There are different kind of systems categories
Technical computer-based systems
The term technical is simply known as hardware component. It includes hardware and software components but it doesn't include processes and procedures. Like there are different kind of technical computer based systems, mobile is technical system, TV (Television) technical computer system. 

Socio-technical system

Socio-technical system means it includes about how the system works and how the system should be used to achieve objectives. Means these systems have process and procedures. This also includes the peoples as operators without operator there no system can run. 

Properties of System

  • Functional emergent properties
  • Non-functional emergent properties

Functional emergent properties

This includes about all the functional part of system. How is works and how to achieve objectives from that system. 

Non-functional emergent properties

These are not related with function. These are related with the behavior of that system. It's environments it's examples are reliability, performance, durability, safety and security. These are the most critical for computer systems.

What is System Engineering?

System engineering is the activity of specifying, designing, implementing, validating deploying and maintaining socio-technical system which i have explained above.

System engineer just not concerned only about hardware parts and it's performance. They will concern about the software also.

A system may include software, mechanical electrical and electronic hardware and be operated by the people. System components are depends on other system which are known as software system. Every system interact with  the environment and system must pass information one to another.

Problems of System Engineering

  • Large systems are usually designed to solve wicked problem.
  • System engineering requires a great deal of coordination across disciplines.
  • System must be designed to last many years in a changing environment. 
  • Missed schedule. 
  • Improper integration of subsystem. 
  • Maintenance problem.
  • Unmanageable system. 

System Engineering Process

There are 7 phases in system engineering process which are very important in system engineering. Without the help of these steps we cannot develop system. 

Requirement definition > system design > sub-system development > system integration > system installation > system decommissioning

System requirement definition
It is required to identify the systems requirements before developing any system. The developer need to consult the users about the system. What kind of system they wants and what features they want in that system.

System design 
After identifying the system requirement, the system needs to be analyzed. The system should be feasible from all aspects. Then the system is designed as per the system requirement & feasibility analysis.    

Sub-system development
The sub-systems are developed according to the design of the system. The design is converted into codes. 

System integration
Integration means grouping or merging. In this phase, the sub-divided system are integrated and tested to check if the system is OK or not

System installation 
The system is installed in the required field after the system is completely tested and evaluated. 

System decommissioning
A system has a life time of any fixed year may be 5 years or 10 years after that time the system will not be used. That system should be replaced with new system. Where the system is abolished as the no longer provide services

Characteristics of a System

  1. Component : Part that is used to make system or sub-system.
  2. Interrelated component: Dependence of one sub-system. 
  3. Boundary: The line that marks inside and outside of the system and that sets off the system from it's environment.
  4. Purpose: The overall goal and function of a system.
  5. Environment: Everything external / internal to a system that interact with the system. 
  6. Interface: Point of contact where a system needs it's environment or subsystem meet each other. 
  7. Input and Output: Whatever system takes and whatever it's displays. 
  8. Constraints: The limits to what a system can accomplish.

System Modelling

It's the one of the important part while designing a system or subsystem. During the system design and requirement activity system may be modelled as a set of components and relationship between these components. These are normally illustrated graphically in a system architecture model that gives the reader user an overview of the system organization.  

An architectural model presents an extract view of the subsystem making up a system. It may includes major information flows between sub-systems. Usually modelling means the presenting as a block diagram to showing the major functions and flow of the information and the data and the interconnection.