System Analysis & Design Lecture 1 PDF

Computer sciences department Misr Higher Institute for commerce & computers System Analysis |& Design lecture 1 Dr. Lobna Mohamed Aboelmagd  Course contents Introduction to information system development process Managing information system project Process requirement...

Computer sciences department Misr Higher Institute for commerce & computers System Analysis |& Design lecture 1 Dr. Lobna Mohamed Aboelmagd  Course contents Introduction to information system development process Managing information system project Process requirement process modeling Data modeling Architecture Design Data Storage Design Program Design User Interface Design Road map  Mid- term  Quizes  Projects ◦ Title ◦ Collect data ◦ Doc. (DFD – ERD) ◦ program  Introduction ◦ Systems analysis and design is a proven methodology that helps both large and small businesses reap the rewards of utilizing information to its full capacity.  As a systems analyst, the person in the organization most involved with systems analysis and design, you will enjoy a rich career path that will enhance both your computer and interpersonal skills. Information systems analysis and design  create and maintain information systems that perform basic business functions such as keeping track of customer names and addresses, processing orders, and paying employees.  The main goal of systems analysis and design is to improve organizational systems, typically through applying software that can help employees accomplish key business tasks more easily and efficiently.  As a systems analyst, you will be at the center of developing this software The analysis and design of information systems are based on:  Your understanding of the organization’s objectives, structure, and processes  Your knowledge of how to exploit information technology for advantage To be successful in this endeavor, you should follow a structured approach. The major goal of systems analysis and design is to improve organizational systems. Often this process involves developing or acquiring application software and training employees to use it. Application software, also called a system, is designed to support a specific organizational function or process, such as inventory management, payroll, or market analysis.  The goal of application software is to turn data into information. ◦ For example, software developed for the inventory department at a bookstore may keep track of the number of books in stock of the latest bestseller. ◦ Software for the payroll department may keep track of the changing pay rates of employees.  A variety of off-the-shelf application software can be purchased, including TurboTax, Excel, and Photoshop. However, off-the-shelf software may not fit the needs of a particular organization, and so the organization must develop its own product.  The information system includes:  the hardware and systems software on which the application software runs.  Documentation and training materials, which are materials created by the systems analyst to help employees use the software they’ve helped create.  The specific job roles associated with the overall system, such as the people who run the computers and keep the software operating.  Controls, which are parts of the software written to help prevent fraud and theft.  The people who use the software in order to do their jobs.  A system is an interrelated set of business procedures (or components) used within one business unit, working together for some purpose.  1. Components  2. Interrelated components  3. Boundary  4. Purpose  5. Environment  6. Interfaces  7. Constraints  8. Input  9. Output Important System Concepts  Decomposition  Modularity  Coupling  Cohesion Decomposition  Decomposition is a technique that allows the systems analyst to:  Break a system into small, manageable, and understandable subsystems  Focus attention on one area (subsystem) at a time, without interference from other areas  Concentrate on the part of the system pertinent to a particular group of users, without confusing users with unnecessary details  Build different parts of the system at independent times and have the help of different analysts  Modularity is a direct result of decomposition. It refers to dividing a system into chunks or modules of a relatively uniform size. Modules can represent a system simply, making it easier to understand and easier to redesign and rebuild.  Coupling means that subsystems are dependent on each other. Subsystems should be as independent as possible. If one subsystem fails and other subsystems are highly dependent on it, the others will either fail themselves or have problems functioning.  Cohesion is the extent to which a subsystem performs a single function. In the MP3 player example, supplying power is a single function. This brief discussion of systems should better prepare you to think about computer-based information systems and how they are built. Many of the same principles that apply to systems in general apply to information systems as well.  Developing Information Systems and the Systems Development Life Cycle (SDLC)  Organizations use a standard set of steps, called a systems development methodology, to develop and support their information systems. Like many processes, the development of information systems often follows a life cycle. For example, a commercial product  IS jobs  Information Systems Manager Information systems managers look at the total information needs of an organization and determine the best way to meet them.  Software Developer.Software developers are responsible for designing, modifying, writing, and debugging software and computer applications for clients based on their specific wants and  Computer Network Architect Another interesting information system job is computer network architect. Also known as an information architect, this person is responsible for codifying all the data in a given building, website, network, or organization. An information architect makes sure information is ergonomic and user-friendly.  Information Security Analyst With the growth in technology usage across all industries comes a heightened need for greater information security.  Database Administrator person stands as a critical component to the IT department and is responsible for managing and backing up systems to ensure the availability of useful data.  Computer Systems Administrator Similar to a database administrator, a computer systems administrator is responsible for designing, managing, and maintaining the computer servers in an organization.  SDLC steps:  (1) planning and selection,  (2) analysis,  (3) design, and  (4) implementation and operation.