The purpose of system is to make system more reliable and efficient for desired work completion 
Step-by-step explanation:
In most of the times, the system analysts operate in a dynamic environment where change is the necessary process . A business application, a business firm or a computer system may be the required environment. In order To rebuild a system, the key elements must be considered which we need to examine are as follows: 
1. Outputs and inputs. 
2. Security and Control. 
3. processor 
4. Environment. 
5. Feedback. 
6. Boundaries and interface.