What is Systems Analysis and Design SA

1
What is Systems Analysis and Design (SAD)?

• A system is a set of related components that work
  together in a particular environment to perform
  whatever functions are required to achieve the
  systems objective
• Systems analysis is the process of studying an
  existing system whether manual or automated --
  and its environment to understand the components
  and functions of the current system, to identify
  the organizations information and processing
  needs and to determine the characteristics of a
  new system to meet these needs.
• System decomposition involves taking a system
  apart to gain a full understanding of its parts.
  Systems can be decomposed into
• Traditional
• Functions Input, Processing, Output, Storage,
  and Control (IPOSC)
• Components People, Procedures, Data, Software,
  and Hardware (PPDSH)
• Subsystems e.g. accounting systems into
  payroll, accounts receivable, etc.
• Object-Oriented
• Objects, Attributes, and Methods
• Systems design is the process of synthesizing or
  reassembling the components and functions
  identified during analysis.

2
The Environment of SAD

• The System Lifecycle
• Development phase an information system is
  analyzed, designed and implemented
• Conversion phase the systems moves from the
  development phase into the production phase
• Production phase the information systems is
  used to perform business functions
• Maintenance the production system is upgraded
  and modified
• Catalysts Impetus for a systems development
  project
• User demand arises out of problems users have
  with the current system
• Technology push arises when new technologies
  enable new ways of doing business
• Strategic pull arises from an organizations
  objectives and strategies
• Goals Criteria by which a systems development
  effort can be judged
• System Quality does the system satisfy the
  organizations information needs, is it easy to
  maintain, and can it adapt to the changing
  environment of the organization?
• Project Management was the system completed
  on-time and within budget?
• Organizational Relevance does the system
  contribute to organizational success?

3
Products of System Development

• Functions a logical function describes a system
  function independent of the technology used while
  a physical function describes a system function
  in terms of the technology used
• Input -- activities performed to access data for
  processing
• Processing ways that data are manipulated to
  perform business functions and produce
  information of value to decision making
• Output activities required to generate business
  documents or reports
• Storage activities required to maintain system
  data
• Control activities performed to verify the
  validity and accuracy of inputs and outputs, and
  to ensure the integrity of stored data
• Components from a sociotechnical perspective
  include not only the technology but also the
  behavioral or social factors that affect how well
  an information system will meet organizational
  and individual requirements
• People users, designers, implementers
• Procedures standard operating procedures
• Data facts collected by an organization to be
  organized into useful information
• Software stored instructions that tell the
  computer what to do
• Hardware the physical equipment used to enter,
  process, output, store and communicate data

4
Systems Development in ContextUsing Competitive
Analysis to Help an Organization Use Information
Technology Strategically

• The information revolution is affecting
  competition in 3 vital ways
• It changes industry structure and alters the
  rules of competition
• It creates competitive advantage by giving
  companies new ways to outperform their rivals
• It spawns whole new businesses, often from within
  a companys existing operations
• The value chain
• Every value activity has both a physical and an
  information processing component the mix of
  both these components determine an organizations
  information intensity
• Sources of competitive advantage
• Careful management of linkages among value chain
  activities and among a company and its suppliers
  and customers
• Perform value chain activities at a lower cost
• Perform value chain activities in a way that
  leads to differentiation and a premium price
  (more value)
• Achieving and appropriate competitive scope

Based on Porter, Michael E. and Victor E. Millar,
How Information Gives You Competitive Advantage,
Harvard Business Review, July-August 1985.