Structured systems analysis and design method Essay

Feasibility Study: Phase 0

This assumes that the proposed undertaking has been identified as a consequence of an exercising such as strategic planning and sets out to measure the assorted proficient, organizational, fiscal and concern options available. The purpose is to set up the whether the way and demands of the undertaking are executable. In kernel this is a sawed-off, higher-level version of Stages 1 and 2 ( demands analysis and demands specification ) .

This should non be an expensive or clip devouring exercising ( upper limit of one squad working for 1/2 months ) . The purpose is to measure the feasibleness of the proposal, affecting an analysis of the job and finding of the best solution ; normally a scope of possible solutions are presented. Context diagrams, current physical DFDs, overview ERDs, a demands catalogue, undertaking direction techniques such as activity webs and Gantt charts are produced. To go through this phase and travel through to system development a proposal must show [ Kendall & A ; Kendall, 1988 ] :

We will write a custom essay sample on
Structured systems analysis and design method Essay
or any similar topic only for you
Order now
  • Economic feasibleness ;
  • Technical feasibleness ;
  • Operational feasibleness ;

Other types of feasibleness may besides necessitate consideration, for illustration legal feasibleness.

Economic Feasibility

The purpose here is to measure the costs required for alternate systems and put them against the expected benefits. The types of options that are often considered are the manual/computer boundaries as some undertakings may profit more than other s from cybernation and non-functional features such as the clip hold between the existent universe and the different parts of the system: should we be looking at batch, online or real-time or a combination? The system costs should besides be estimated in footings of basic resources of money, people and clip. For illustration, the undermentioned must be costed:

  • Systems development, for illustration in-house or direction consultancy ;
  • User clip for demands acquisition, proving and preparation ;
  • Hardware & A ; package costs.

Set against the costs should be a quantifiable appraisal of the expected benefits, for illustration reduced labour costs, improved client service or predicted addition in orders. Economic feasibleness is a spot of a ‘black art ‘ , it ‘s hard to foretell with any grade of certainty whether a system will in fact benefit an administration. The most often missed cost is the cost of keeping the system once it is installed.

Technical Feasibility

This is concerned with whether the solution can be implemented utilizing bing engineering. If it can so bing engineering may necessitate upgrading or adding to. If it can be done so the solution may necessitate the integrating of equipment or package that has non been combined before. Non-functional demands such as batch or online processing, maximal response clip for user-computer interaction, estimated frequence of minutess, upper limit record and file sizes, networking tonss and typical figure of users are considered here. In add-on, demands of system enlargement, security, informations archiving and dependability are considered.

Operational Feasibility

This investigates factors such as the likely reaction of employees and brotherhood representatives to occupation and other proposed organizational alterations. The chief purpose is to measure whether the solution will run and be used after installing. For illustration, if users are happy with the current system and see no ground to alter so there may be a high grade of opposition to the new proposal. Relevant factors here concern whether the solution has general direction support and whether or non the users have been involved in the development of the proposal.

Legal Feasibility

This encompasses a wide scope of topics including contracts, liability and the Data Protection Act.

Feasibility Report

The consequence of the feasibleness survey should be a feasibleness study that provides a elaborate footings of mention, a direction sum-up, inside informations of how the feasibleness survey was undertaken, analysis of the current state of affairs, inside informations of the hereafter demands, account of the proposed system, inside informations of options that were rejected, a fiscal appraisal of the costs and benefits of developing the proposed system, a undertaking program and recommendations.

Requirements Analysis: Stages 1 & A ; 2

This consists of 2 phases. In phase 1 demands are defined by look intoing the current environment and placing jobs or countries that need betterment. Phase 2 so develops a scope of options that meet the defined demands and selects one option as the footing for the coveted system.

Phase 1: Probe of Current Environment

An overview of the current processing and information is created. Current jobs are documented as a necessary betterments and any new informations or maps that will be required. The intended users of the new system are besides identified.

  • A DFD is produced demoing the current system.
  • An ERD is produced demoing the entities and relationships obtained by analysis of the informations in the current system.

Phase 2: Business Systems Options

A Business System Option ( BSO ) describes a suggested new system in footings of its functionality and its boundary: inputs, end products, procedures and informations are described. The purpose is to assist the users choose, from all the listed demands, merely what they want their new system to make.

A BSO is a textural description of the boundary, inputs and end products, and rule processing activities ( or maps ) to be performed of a proposed system. The BSO may include diagrams ( DFDs, ERDs etc. ) . However, such diagrams would be really much an overview.

Technique: Draw up a list of about 6 BSOs, covering a scope of demands identified in Stage 1. The scope should cover:

  • One option that covers the declared minimal demands and no more ;
  • One option that covers every new demand ;
  • Up to four options that each screen the stated minimal demand and a different set of the other demands.

The six options will so cover six different boundaries and six different functionalities – all will cover the minimal functionality required.

Non-functional demands should besides be covered, for illustration:

  • Cost/benefit of the proposed option ;
  • Impact Analysis of implementing the BSO ;
  • Timescales for development and building.

The obvious non-starters can so be eliminated. The staying BSOs should so be extended to include:

  • Constraints ;
  • Impact on bing systems – expression out for the ripple consequence ;
  • Detailed programs and clip graduated tables for the subsequent SSADM activities and execution of the system ;
  • Organizational impacts and deductions.

The short-listed BSOs should so be presented to the determination devising organic structure.

Requirements Specification: Phase 3

Having selected a specific BSO a elaborate specification of demands now begins. The accent is on finding the coveted system informations, maps and events. Prototyping techniques are besides suggests for the development of the HCI.

  • The antecedently defined skeletal DFDs and ERDs are modified and refined to fit the demands in the selected BSO ;
  • All properties are specified for the ERD ;
  • Non-functional features such as security, entree and archiving demands are defined ;
  • The input/output informations is defined utilizing ‘input/output constructions ‘ ;
  • The system duologues are defined ;
  • As a cheque on the ERD ‘relational information analysis ‘ is used ;
  • Prototyping the demands with the users to obtain mistakes and gaining control any extra demands is suggested. SSADM provides processs for pull offing prototyping Sessionss ;
  • Using ‘entity-event patterning ‘ more elaborate processing demands are obtained, This is done by making an ‘entity life history ‘ for each entity on the ERD, and an ‘effect correspondence ‘ diagram is constructed for each event, demoing the entities affected by that event. An ‘enquiry entree way ‘ is created for each awaited question demoing the entities on the ERD that are to be accessed.

Logical System Specification: Stages 4 & A ; 5

Phase 4: Technical System Options

This assesses the different options for implementing the specification and describes the costs, benefits and restraints. Factors include internal and external restraints. External restraints consist of, for illustration, clip, cost, concern public presentation and any hardware or package restraints set in the feasibleness survey.

The process for bring forthing and choosing Technical System Options ( TSOs ) is really similar to that for BSOs. First, pull up an initial list of about six options. The skeletal TSOs should so be expanded to include inside informations derived from possible providers such as:

  • Cost ;
  • Facilities ;
  • Performance ;
  • Support etc.

The purpose is non to make up one’s mind on a pick of seller but to set up ballpark figures and estimations to show to the Project Board for each TSO. As with BSOs, the scope should cover:

  • One option that suggests no alteration ;
  • One option that covers the declared minimal demands and no more ;
  • One option that covers every new demand ;
  • Up to four options that each screen the stated minimal demand and a different set of the other demands.

The scope should so be examined to extinguish obvious non-starters. The staying TSOs should so be presented to the board

Phase 5: Logical Design

The Logical Dialogue of the system is defined. This does non include the physical duologues ( menu constructions, signifier designs etc. ) . Neither is this the phase at which the physical screen features are defined. At this phase the logical exchange of informations is defined.

The Update Processing is besides defined. This specifies the logic of each database update required for an event. The Entity Life Histories are updated with State Indicators. State Indicators describe the specific province of the informations associated with each event in the ELH. For illustration, when a Customer Record is created the initial province of all the properties is empty. As the Customer Record is processed the province of the properties will alter over clip.

Physical Design: Phase 6

The Physical Environment the system will run in is considered.

A Physical Environment Classification Scheme is used to categorise the physical environment. The strategy considers factors including:

  • Data storage ;
  • Performance ;
  • Processing features.

The features, demands and restraints of the environment will clearly hold an consequence on interlingual rendition from the Logical Design. Decisions such as denormalising, constellating and indexing will be made at this clip.

The physical screen designs are developed.


  • [ Kendall & A ; Kendall, 1988 ] Kendall K E & A ; Kendall J E, Systems Analysis & A ; Design, Prentice Hall, 1988
  • [ Downs, Clare & A ; Coe,1992 ] SSADM: Application and Context, Prentice Hall, 2nd Edition, 1992

Hi there, would you like to get such a paper? How about receiving a customized one? Check it out