Chapter 10 Developing Information Systems

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Chapter 10Developing Information Systems

• The Systems Development Life Cycle (SDLC)

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All successful systems follow a planning
implementation process
And now, behold, I say unto you, that these are
the generations of the heaven and of the earth,
when they were created, in the day that I, the
Lord God, made the heaven and the earth. And
every plant of the field before it was in the
earth, and every herb of the field before it
grew. For I, the Lord god, created all things,
of which I have spoken, spiritually, before they
were naturally upon the face of the earth. Moses
34-5
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The need to build or change an Information system
stems from many potential factors

• changing government regulations
• problems in the current IS
• customer (market) demands
• employee suggestions
• management changes/requests
• corporate growth, expansion, acquisition
• changing business/industry
• changing technology
• competitive pressures

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Systems Development

• Creating an information
• system can be compared
• to building a house.
• The process of planning
• building an information
• system is called
• systems analysis and design.

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SDLC

• The system development life cycle (SDLC) is an
  outline of a process that helps develop
  successful information systems.
• divided into phases
• each phase includes many sub-tasks

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Systems Development Life Cycle

• 1. Systems Investigation
• (Basic understanding Problem Project Plan
  including feasibility analysis)
• 2. Systems Analysis
• (Complete understanding of problem and solution
  System Requirements)
• 3. Systems Design
• (Analyze possible solution approaches, then plan
  and develop best solution Application Specs.)
• 4. Systems Implementation
• (Construct system and Convert Working System)
• 5. Systems Maintenance Review
• (Evaluate, Adjust, Update Minor Modifications)

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Systems Analyst(Compare a home Architect)

• Computer professionals called systems analysts
  are responsible to
• Assist with feasibility assessment
• analyze info requirements (details)
• create requirements specifications
• Help design the system
• Help programmers understand the specifications
• Supervise the implementation
• Systems analysts are a bridge between business
  and technology.

Spans Entire SDLC
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Phase 1 Investigation(Compare Think about
building a new house, talk to potential
architects and contractors, prepare construction
plan)

• Systems Planning steps include
• Select the project team
• Abstract understanding of problem
• Justify project in general terms
• Choose development methodology
• Develop a preliminary project schedule
• Produce preliminary project development plan
• Systems Development is done by a project team of
  technicians, managers, users generally
  supervised by the IS department

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Feasibility Assessment(Compare Can I afford a
new home? Will it meet my needs?)

• Economical
• Do benefits exceed costs?
• Technical
• Is technology available - are we up to it?
• Operational
• Can our organization operate it?
• Legal
• Does it meet all regulations and laws?
• Scheduling
• Is the implementation schedule practical? Have
  we allowed time for building, testing, training,
  etc.?

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Consider The Exxon Mobil Case
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Phase 2 Systems AnalysisWhat must the system do
to solve the problem?(Compare What are a
familys needs in a home?)

• Systems Analysis steps include
• Collect Data Study the current system
• Analyze Data
• Determine system requirements
• Write requirements report
• Note Tools for systems development will be
  covered later.

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Determine System Requirements(Compare What is
needed in a home to meet family needs?)

• System requirements are the specifications
  criteria for successfully solving the identified
  problems by using an information system.
  (Compare What are family requirements in a home)
• Approaches may include JAD, RAD, Prototypes

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Phase 3 Systems Design (E.g. Architects House
Plans)

• Systems Design steps include
• Identify potential alternative solutions
• Get Vendor/Supplier information RFI, RFQ, RFP
• Evaluate solutions recommend a choice
• (Preliminary Evaluation, Final Evaluation)
• Contract with suppliers (include detailed
  requirements, milestones, penalties)

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Acquiring Hardware Software(Compare Choose a
builder get materials)

• Request for information (RFI) a document that
  seeks information on a product, vendor, or
  process, etc.
• Request for proposal (RFP) a document that
  describes the information system problem and the
  requirements for the solution and requests that
  a vendor submit a proposal.
• request for quotation (RFQ) request for a formal
  price quotation on a list of hardware and
  software.
• Application specifications describe the way that
  an application should interact with the user,
  store data, process data, and report results.

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Phase 4 Implementation (Compare Build,
inspect, move in, use the house)

• Steps in the Systems Implementation Phase
• Acquire hardware, software telecom equipment.
• (Rent, buy, lease decisions)
• Prepare Users (Train on new system)
• Hire Train Computer Systems Personnel
• Write custom computer programs
• Prepare site
• Prepare (build/convert) Database
• Install System
• Test system
• Convert/Start new system
• Get User Acceptance

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Testing

• Uniteach module
• Systemmodules can talk to each other
• Volumecan handle large volumes of traffic/data
• Integrationworks with our other systems
• Acceptanceeverything works in accordance with
  the contract

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Startup (Conversion) Acceptance(Compare Move
In Start Living in house)

• System conversion techniques
• Direct conversion switch from the old system to
  the new one overnight
• Parallel conversion avoids some risk run the
  old system until the new one is activated and
  working.
• Phased conversion activate a new system one
  module at a time.
• Pilot conversion Activate and test the new
  system in one branch of an organization.

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Do the CRS Case
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Phase 5 Maintenance(CompareUp-keep on a home)

• Steps in the System Maintenance Phase
• Operate the equipment
• Follow backup procedures
• Very important _at_ WTC and Gulf Coast!!
• Help users
• Identify and fix problems
• Optimize for speed and security
• Modify systems to meet changing needs

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Maintenance is HUGE!

• Application software modifications consume a
  significant share of IS department resources.
• fix bugs
• add new features
• deal with new versions of vendor software
• Some IS organizations spend 70 (or more) of
  their budget on software maintenance.

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Maintenance Cost Pattern

• An information system requires the most
  maintenance during the beginning and end of its
  useful life span.

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Completing the Cycle (SDLC)(Compare Eventually,
Current home becomes inadequate build a new one)

• End-user support is a major maintenance activity
• A help desk is staffed by a support technician
  who is familiar with the application software.
• Maintenance continues until the information
  system is no longer cost-effective or becomes
  obsolete.
• Then the CYCLE (SDLC) starts over!!!

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Some Career Options

• Systems Analyst
• Systems Designer
• Systems Programmer
• Project Manager
• CIO

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Do the Boeing Case
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QUIZ