Principle of System Analises
SYSTEM ANALISYS AND DESIGN – ASSIGNMENT 1 PRINCIPLES OF SISTEM ANALYSIS Name: Julius Cabral De Souza Enrolment Number: A127113A Course: Access to Computing, Business Systems and Accounts Task 1 Mulchester Caravans Purpose The purpose of the process is to record essential details of customer’s bookings, payments and to record details about the owner of each caravan on site. ... A clerk checks the system for availability before the booking confirmation. ... Constraints Some constraints have been set by the costumer, which will limit the options that can be presented as part of the system proposals. ... They require any new system to run on their present mainframe computer. ... In addition, requirement of system expansion security, data archiving and reliability are considered. ... For example, if users are happy with the current system and see no reason to change then may be a high degree of resistance to the new proposal. ... The types of alternatives that are frequently considered are the manual/computer boundaries as some tasks may benefit more than others from computerization and non-functional characteristics such as the time delay between the real world and the different parts of the system. The system cost should also be estimated in terms of basic resources of money, people and time. ... Secondly then develops a range of options that meet the defined requirements and selects one option as the basis for the desired system. ... The intended users of the new system are also identified. - A Data Flow Diagram is produced showing the current system. - An Entity Relationship Database is produced showing the entities and relationships obtained by analysis of the data in the current system. Stage 2 - Business Systems Options (BSO) A Business System Option describes a suggested new system in terms of its functionality and its boundary: inputs, outputs, processes and data are described. The aim is to help the users choose, from all the listed requirements, just what they want their new system to do. A BSO is a textural description of the boundary, inputs, and principle processing activities (or functions) to be performed of a proposed system. ... The remaining BSOs should then be extended to include: - Constraints; - Impact on existing systems; - Detailed plans and time scales for the subsequent SSADM activities and implementation of the system; - Organisational impacts and implications. ... The emphasis is on determining the desired system data, functions and events. ... - The previously defined skeletal DFDs and ERDs are modified and refined to match the requirements in the selected BSO; - All attributes are specified for the ERD; - Non-functional characteristics such as security, access and archiving requirements are defined; - The input/output data is defined using ‘input/output structures’; - The system dialogues are defined; - As a check on the ERD ‘relational data analysis’ is used; - Prototyping the requirements with the users to obtain errors and capture any additional requirements is suggested. ... Documentations used in SSADM Data Flow Diagrams A Data Flow Diagram (DFD) is a diagrammatic representation on the information flows within a system, showing: - How information enters and leaves the system; - What changes the information; - Where information is stored. ... DFDs are used not only in structured system analysis and design, but also as a general process modelling tool. ... The logical information processing of the current system; - Required Logical DFDs. The logical information processing requirements of the proposed system. DFDs show the passage of data through the system by using 5 basic constructs: Data flows, Processes, Data Stores, External Entities, and Physical Resources. ... External Entities The external entity represents a person or a part of an organisation which sends or receives data from the system but considered to be outside the system boundary.