Phase 2

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Phase 2 Systems Analysis

• Transition to Systems Design
• Chapter 6

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Objective

• Evaluate software alternatives and development
  strategies.
• Explain advantages and disadvantages of
  developing in-house software versus purchasing
  and customizing software.
• Describe how companies use outsourcing and user
  applications.
• List the steps in purchasing and evaluating a
  software package
• Explain the differences between a request for
  proposal (RFP) and a request for quotation (RFQ).

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Objective

• Describe the system requirements document and the
  presentation to management at the end of the
  systems analysis phase.
• Explain the transition from systems analysis to
  systems design, and the difference between
  logical and physical design.
• Explain the importance of prototyping and
  describe various prototyping methods, tools, and
  techniques.
• Discuss the system design process.
• Create and use appropriate codes during systems
  design and development.

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SOFTWARE ALTERNATIVES

• DEVELOP IN-HOUSE
• PURCHASE SOFTWARE PACKAGES

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IN HOUSE

• Software developed by technical staff in a
  companys information systems department

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SOFTWARE PACKAGE

• Software written by another company and available
  for purchase
• commercial application software
• available for sale by software publishers or
  software vendors

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HORIZONTAL SOFTWARE

• Software package that can be used by many
  different types of organizations
• Accounting
• Invoicing
• Accounts payable

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VERTICAL SOFTWARE

• Software developed to handle requirements of IS
  for specific type of organization
• colleges
• banks
• insurance companies
• doctor offices

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Developing Your Own Software

• Satisfy unique requirements
• Minimize changes to business procedures and
  policies
• meet constraints of existing system
• meet constraints of existing technology
• utilize new technology

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Buying a Software Package

• Less expensive
• Less time to implement
• Fewer errors
• Already in use in other companies
• Requires fewer technical staff for development
• Upgraded by vendor
• ????????

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Customize Software Packages

• Off the shelf package
• vendors standard package
• Customized package
• a software package that YOU or the VENDOR modify
  to meet your unique specifications

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Customizing Software Packages

• Vendor makes modifications
• and time
• YOU make modifications
• time , money and technical expertise
• Add on supplemental components

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Application Service Providers

• ASP
• Delivers applications, or access to applications,
  by charging a usage or subscription fee
• Application hosting

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Outsourcing

• Use of outside company to handle a portion of
  companys IT work load
• Either temporary or long-term
• Advantages??
• Disadvantages??
• consulting firms
• consultants
• contract programmers

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User Applications

• Typically use standard business software (Office
  2000), to allow user to perform tasks

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User Applications

• Development of entire/portion of IS by end users
  for a company
• limited to end user department
• not integral to central IS
• spreadsheets, database reports
• often 4th generation tools

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User Applications

• WHY
• NOT ENOUGH TIME FOR IS TO DO EVERYTHING

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Selecting Software Steps

1. Evaluate IS requirements
2. Identify potential software vendors
3. Evaluate software package alternatives
4. Make the purchase
5. Install the software package

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Evaluate IS Requirements

• Identify key features of IS
• Identify IS current volume and future growth
• Specify IS external constraints
• hardware and software
• REQUEST FOR PROPOSAL -- RFP

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Identify Potential Vendor

• PC, midrange, mainframe, network????
• Horizontal vs Vertical
• Computer store (PC only)
• Hardware manufacturers
• Industry trade magazines
• Relative cost for pc vs mainframe

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EVALUATE SOFTWARE PACKAGE ALTERNATIVES

• Compare identified possible software package
  solutions
• vendor presentations
• Existing users
• benchmarks
• literature
• evaluations in trade journals
• evaluations from market research
• try it yourself

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EVALUATE SOFTWARE ALTERNATIVES

• BENCHMARK TEST
• measure time it takes to process set number of
  transactions
• compare different software results

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MAKE THE PURCHASE

• WHAT DO YOU ACTUALLY PURCHASE??
• SOFTWARE LICENSE
• right to use the software under certain terms and
  conditions
• single computer restriction very common

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MAKE THE PURCHASE

• network?? -- site license
• leasing agreements
• MAINTENCE AGREEMENT
• give you the right to contact vendor for
  assistance

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INSTALL SOFTWARE

• IMPLEMENTATION
• Load software
• Test software
• Train end users
• Convert data to system files

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HARDWARE ALTERNATIVES

• Request for Quotation
• Request for Bid

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TURNKEY SYSTEM

• Complete IS that includes all hardware, systems
  and application software, documentation,
  training, installation, and support from outside
  vendor
• Usually used in smaller companies

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COMPLETION OF SYSTEMS ANALYSIS

• Systems Requirement Document
• Formal Presentation

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SYSTEMS REQUIREMENTS DOCUMENT

• Management Summary
• IS Background
• Functional Requirements
• Environmental Requirements
• Alternatives
• Recommended Alternatives
• Time and Cost Estimates
• Appendices

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SYSTEMS REQUIREMENTS DOCUMENT

• Could be lengthy!!!

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Presentations after Systems Analysis Phase

• One of the most critical milestones in entire SDLC

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POSSIBLE MANAGEMENT DECISIONS

• Develop in-house
• Modify current system
• Purchase software package
• Purchase and develop in house
• Perform additional systems analysis
• Stop all further work

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CHANGE CONTROL

• Process of managing and controlling the requested
  changes in requirements for an information system

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CHANGE CONTROL

• Freeze the requirements
• maximize chance for successful delivery of IS
  that satisfies requirements within projected
  costs and schedules
• Change is inevitable

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Transition to Systems Design

• Analysis Phase logical or essential model
• Logical design of IS defines the functions and
  features of system and relationships among its
  components
• Includes the output that must be produced, the
  input needed, processes that must be performed
• without regard to how tasks will be accomplished
  physically

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Transition to Systems Design

• Design Phase physical model
• Physical design of IS is a plan for the actual
  implementation of the system
• Built on logical design
• Describes the actual processes of entering,
  verifying and storing data, physical layout of
  data files, sorting procedures, exact format of
  reports

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PROTOTYPING

• Early, rapidly developed working version of IS
  that exhibits the essential features of the
  target IS
• working model

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Approaches to Prototyping

• System prototyping full-featured, working model
  of IS, ready for implementation
• RAD
• Design prototyping (throwaway)
• Used to verify user requirements, after which the
  prototype is discarded
• Gives us a user approved design

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PROTOTYPING TOOLS

• Procedural vs. non-procedural tools

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Prototyping Tools

• Data Dictionary
• RDBMS
• report generator
• query language
• screen generator
• application generator
• 4 GL

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Prototyping during Systems Analysis

• given to end users to evaluate how well it
  satisfies their needs
• working model -- changes made often
• takes time to develop and evaluate
• lower costs in later phases of SDLC

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CASE TOOLS

• SOFTWARE PRODUCT THAT AUTOMATES A SPECIFIC
  SYSTEMS LIFE CYCLE TASK
• Screen generator
• Computerized data dictionary
• Advantages and Disadvantages of
  CASE tools

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ALTERNATIVE GRAPHICAL TOOLS

• System flowchart

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SYSTEMS DESIGN

• Look carefully at system requirements from
  systems analysis phase to complete system design

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• Components of IS are interdependent
• First must thoroughly understand entire logical
  design before beginning physical design

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First step of System Design

• Review system requirements document from Systems
  Analysis phase
• analyst assigned to design may not have
  participated in analysis
• time has passed since analysis phase

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SYSTEM DESIGN ACTIVITIES

• Need to consider IS components of data, data
  stores, people, procedures, hardware, software,
  and information interrelationships

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DESIGN TIPS FOR SYSTEM DESIGN

• End user considerations
• Data considerations
• Processing considerations

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Designing and using Codes

• Code a set of letters or numbers that represent
  a data item
• Can be used to simplify output, input and data
  formats
• Consider early in design phase
• Efficiency

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Types of Codes

• Sequence
• Block sequence
• Alphabetic
• Category
• Abbreviation
• Significant digit

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Types of Codes

• Derivation
• Cipher
• Action
• Self-checking