Name: Ruth Ann S. Basnillo

Section: O0A

Book: Systems Analysis and Design Fifth Edition

Authors: Kenneth Kendall

             Julie Kendall

Reference No: QA 76.9 S88 K45 2002

Chapter: One

Quote: “You can't just punch in ' let there be light' without writing the code underlying        the user interface functions."

Review: 

 

The Systems Development Life Cycle

 

     Systems Development Life Cycle, also called SDLC, is a phased approach to Systems Analysis and Design that holds that systems are best developed through the use of a specific cycle of analyst and user activities. It is, in short, a systematic approach to solving business problems. This life cycle is divided into seven sequential phases namely: (a) identifying problems, opportunities, and objectives; (b) determining information requirements; (c) analyzing systems needs; (d) designing the recommended system; (e) developing and documenting software; (f) testing and maintaining the system; and (g) implementing and evaluating the system.

 

Phase 1: Identifying Problems, Opportunities, and Objectives

 

     This is the first phase of the SLDC wherein the analyst look honestly about what is happening in the business and pinpoints the problems together with other organizational members. This stage is so critical because it would affect the other phases of the system if the wrong problem was addressed. Opportunities meanwhile are the situations that can be improved using computerized information system that could help make a business competitive. Setting objectives to be met is also important to be able to know what problems or opportunities could be addressed, and to discover what the business is trying to do.

 

     People involved:

          1. analyst

          2. systems management

          3. user management

 

     Activities in this phase:

          1. interviewing the user management

          2. summarizing the knowledge obtained

          3. estimating the scope of the project

          4. documenting the results

 

   

 

  Output of the phase:

          feasibility report containing the problem definition and the summary of the objectives

 

Phase 2: Determining Information Requirements

 

     This second phase of the SDLC is where the analyst determines and understands what information users need to perform their jobs. This is where the WHO (people involved), WHAT (business activity), WHERE ( environment where the work takes place), WHEN (timing), HOW ( how the current procedures are performed), and WHY ( reason for using) of the current system are studied. Tools such as interviewing management and operations personnel, gathering systems or operating documents, using questionnaires, and observing requirements in the business are used to define the requirements.

 

     Personnel involved:

          1. analyst

          2. user management

          3. user operations

          4. system management

 

Phase 3: Analyzing System Needs

 

     The next phase of the SDLC is analyzing systems needs wherein special tools and techniques are used. One tool that analyst uses is the creation of data flow diagrams, to put in a structure graphical form the IPO (Input, Processes, Output) of the business's functions. Another thing is the analysis of the structured decisions to determine the conditions, condition alternatives, actions, and action rules made. This includes the three major methods like the structured English, decision tables, and decision trees. Next is making semi structured decisions wherein the analyst examines decisions based on the degree of decision- making skill required, degree of problem complexity, and the number of criteria considered when the decision is made. Then, a systems proposal, which includes the summary of what has been found, provision of the cost/ benefit analyses of alternatives, and recommendations for the optimal solution to management, is presented ad prepared.

 

Phase 4: Designing the Recommended System

 

     This design phase of the SDLC is where the systems analyst uses the gathered information to create the logical design of the information system. The interface, which connects the user with the system, is devised so that accurate date- entry procedures make sure that data going into the information system are correct. Moreover, effective input is also provided through the use of goof form and screen design techniques. Files or databases that will be a basis for all information systems are designed to provide the data needed by the decision makers. Lastly, controls and backup procedures are designed to protect the system and the data, and to produce program specification packets that will be used by programmers. Including these is the production of decision trees or tables.

 

Phase 5: Developing and Documenting Software

 

     In this phase, the analyst works with two people- the programmer and the user. The analyst works with programmers to develop any original software needed wherein structured techniques to design and document it are used. These include the structure charts, Nassi- Schneiderman charts, and pseudocodes. The analyst also works with the users to develop effective documentation for software with help files, procedure manuals, and websites like FAQ (Frequently Asked Questions). Programmers have a key role in this phase because they are the ones who design, code, and remove syntactical errors from computer programs. A programmer may also conduct either a code or design walkthrough to explain complex portions of the program to a team pf other programmers, and to ensure quality.

 

Phase 6: Testing and Maintaining the System

 

     This is where the information system is tested first before handing it over to the users. Maintenance, meanwhile, which begins in this phase, is actually carried out routinely throughout the life of the information system. Much of the programmers’ routine work is focused on this and businesses spend a great deal on it.

 

Phase 7: Implementing and Evaluating the System

 

     This phase involves training users to handle the system. Here, the analyst plans for a smooth conversion from the old system to the new one by converting files from old formats to new ones, or building a database, installing equipment, and bringing the new system into production. Evaluations shown mostly for the sake of discussion and actually takes place during ever phase wherein there is a key criterion that must be satisfied.

 

The Impact of Maintenance

 

     Maintenance is performed after the installment for two reasons: to correct software errors and to enhance the software's capabilities in response to changing organizational needs. Some researchers estimate that the amount of time spent on system maintenance may be as much as 60 percent of the total time spent on system projects. In enhancing the software's capabilities, one of the following three situations is generally involved:

 

          1. Users often request additional features after they become familiar with the computer system and its capabilities.

          2. The business changes over time.

          3. Hardware and software are changing at an accelerated pace.

 

     In conclusion, maintenance is an ongoing process over the lifecycle of an information system. It usually takes the form of correcting previously undetected bugs and updating the system with few minor enhancements. But as business and technology change as time goes on, effort on it increases dramatically.