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Stage 5: Maintenance

28 Feb

At last the fifth and final phase of SDLC!!!

The final phase of SDLC is Maintenance. Since the system is up and running and in full use by the organization from the previous stage (implementation), this phase does exactly what it says… maintaining it!!!

So things that occur in this phase could be making requested changes from the users, monitoring the system and fixing and problems and perhaps software changes.

The outcomes of this phase are:

  • keeping the system live (this is necessary after developing a successful project)
  • maintaining a code
  • updating software when it is needed (three things which may happen to software include bug fixing, updating & enhancement)

I suppose you could say that this phase is never ending as it is constantly monitoring and maintaining the new existing system which is in place. That is until of course the system has to be replaced by a new system for whatever reason it may be and the cycle starts back at stage one to develop a replacement system.

Here is an example taken from http://www.ehow.com/about_6735362_maintenance-phase-software-life-cycle.html , which outlines how Microsoft continually maintain and update Windows:

 “Microsoft provides continual maintenance of existing software programs throughout the life of the software through the Windows Update website. Although support for some products is gradually phased out, the maintenance phase for Microsoft software typically covers a span of several years. In the case of Microsoft Office 2007, updates to the software are released in service packs. Support for each released service pack continues for up to 24 months after the service pack is release.”

Here’s a quick overview/summary of SDLC to refresh your memory!
  • SDLC = Systems Development LifeCycle
  • The development of a new system are arranged into phases:
  • 1. Planning [ identify a problem to be solved, form a team, deliver a general problem statement]
  • 2. Analysis [study & analyse current system, define new system objectives, define user requirements, what should the IS do]
  • 3. Design [describes how the parts of the IS should be implemented, create logical design & physical design]
  • 4. Implementation [coding: convert physical system spec into working comp code, develop system, train users,test,  implement = installation]
  • 5. Maintenance [monitoring performance, fixing problems, making requested changes, updating software = keeping the system live]

Hope you found this somewhat beneficial!

Sources:

http://ezinearticles.com/?Definition-of-SDLC-and-Its-Phases&id=2817306

www.cathaldoyle.com

http://softsmith-testing.blogspot.ie/2011/11/sdlc-coding-testing-implementation.html

 

Stage 4: Implementation

28 Feb

The fourth phase in SDLC is Implementation

It entails converting physical system specifications into a working system. The system is developed, tested and implemented.

This is a crucial step which involves converting from the old system to the new system. There are four types of conversions:

  1. Parallel [the old system + the new system are used while the new system is being tested, when the new system is working, the organization stops using the old system]
  2. Pilot [a small group of people use the new system while the rest of the organization continue to use the old system. when the new system is fully working for the pilot group, then the rest of the organization switch over and use the new system too]
  3. Phased [the organization switches from the old system to the new system one component/step at a time until the whole new system is fully in place]
  4. Plunge [this involves switching from the old system to the new system in one go]

Essentially what this phase entails is the construction and installation of the new system.

Some of the activities that occur in this stage include:

  • Coding {physical design specifications converted into a working computer code}
  • Integration and Testing {create a testing environment to bring all the components together, this could be done using one of the four conversion phases as mentioned above}
  • Installation {the new system is having the new system fully in place with all parts of the organization using it

An outcome of this phase is, obviously enough, a fully installed system across the organization. But the system will not operate properly unless users are fully trained to use the system which is a vital element of implementing the system. And another outcome is user and operational documentation.

The next phase in the SDLC is Maintenance. I will discuss this in my next blog post along with a quick overview/summary of the SDLC!

Sources:
http://databasemanagement.wikia.com/wiki/SDLC

http://www.youtube.com/watch?v=TjkUGA512CU

www.cathaldoyle.com

Stage 3: Design

27 Feb

The third phase in SDLC is Design

In the previous stage, analysis, it addressed what can be done for the new system. So in this phase, design, it will set out how the parts of the system should be implemented in order to fulfil user requirements. Keep remembering that the design phase is all about HOW.

A logical design and a physical design must be created in this stage.

What is the difference between logical design and physical design? Well, logical design outlines what the functions of the system are. Then on the other side, physical design is a plan outlining how the system will be implemented.

Logical information resources include components such as data, processes, inputs and outputs. On the other hand, physical components outline how it will be implemented. The logical design is converted into the physical design.

Some techniques used to describe the system design include flow charts and data flow diagrams.

The steps involved in the design phase are:

  • Choosing DBMS (data base management system)
  • Establishing security standards for the system
  • Interface design (including features which allows users to interact with the system)
  • Data Capture Requirements
  • Standards for printed report production
  • System navigation methods

Some of the key deliverables from the design phase include:

  • Function Specification Document (outlines components such as data, inputs, outputs)
  • Technical Specification Document (including files and programs)
  • Implementation Schedule

It is also important to note that coding does not take place in this stage, it takes place in stage four: implementation. This phase of the SDLC will be discussed in my next blog post.

Sources:

http://oer.nios.ac.in/wiki/index.php/Phases_of_System_Development_Life_Cycle#System_Design

http://it.toolbox.com/blogs/irm-blog/logical-vs-physical-design-do-you-know-the-difference-9011

http://books.google.ie/books?id=rAL1KDQhk18C&pg=PA309&lpg=PA309&dq=physical+design+SDLC&source=bl&ots=3wS7jrrgWo&sig=KssKIEYgd7pwSYrgmfURQpQaynk&hl=en&sa=X&ei=fJkuUY-AH42whAfxvYGoBA&ved=0CDEQ6AEwAQ#v=onepage&q=physical%20design%20SDLC&f=false

www.cathaldoyle.com

Stage 2: Analysis

20 Feb

The second phase of SDLC is Analysis.

There are three steps in the Analysis stage:

  1. Understanding the old/current system(collect facts from existing users)
  2. Identifying how the old/current system can be improved (approach users and use different data gathering techniques)
  3. Developing specifications for the new system (what are possible solutions)

 

Data Gathering Techniques include:

  1. Traditional Methods [Interviews, Surveys, Observation and Studying Business Documents]
  2. Modern Methods [Joint Application Design, Prototyping and Group Decision Support Systems]
  3. Radical Methods [Business Process Re-engineering]

 

Key Deliverables:

  1. Business Requirements Document
  2. Data Flow Diagram of Current System
  3. Entity Relationship Diagram of Current System

 

  • The analysis phase addresses what can be done for the new system.
  • The design phase will set out how it can be done in my next post.

Sources:

http://www.youtube.com/watch?v=wlZkZganK-Y

www.cathaldoyle.com

 

Stage 1: Planning

7 Feb

Planning is the first stage in SDLC. It involves the system analyst receiving a request from the user of the potential system. This phase will determine how feasible the proposed project is and whether they should proceed or not in developing the system. A problem is identified to be solved. A team is established. The following documents are developed: project charter, business case and project feasibility.

The key deliverables from this stage include: a  general problem statement, establish a team (each member is assigned with their own roles) and a feasibility report.

If the project proves to the feasible, it is then passed on to the analysis phase, phase 2, which will be discussed in my next post.

References:

System Development Lifecycle (SDLC) in IS

29 Jan

System Development Lifecycle (SDLC) is a process of creating information systems and the models that people use to develop information systems. It can correct a problem or improve an existing system. Its main advantages include: easing the process of creating an information system, helps to reduce failures and ensures that a system will meet its user’s needs. There are five stages in the SDLC: planning, analysis, design, implementation, maintenance.

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