An information system is a
collection of people, hardware, software, data, and procedures that interact to
generate information to support users in an organization.
Business Intelligence systems
collect data that can be used by a company to help make business
decisions. Two common business
intelligence systems are:
- Data Warehousing: a comprehensive collection of
data about a company, its customers, and its business transactions. This data is put into a form that makes
it easy to perform complex queries.
Data warehouses can become very large. For example Wal-Mart’s data warehouse
can hold over 200 terabytes of data.
- Data mining: intelligent SW used to scan a data
warehouse for patterns and relationships within the data that may not be
apparent to management. Another
common use of data mining is customer profiling—which attempts to match
customers with products they would be likely to purchase.
There are many types of
information systems:
- Office systems:
HW and SW that increase productivity and enable communications
- Transaction processing systems: systems that
enable businesses to perform routine transactions, such as order-entry,
payroll, and accounting systems
- Management information systems: systems that
provide managers and executives information they need to make business
decisions. MIS tools include data
mining programs, Excel and various database management system programs
- Electronic data interchange (EDI) systems:
systems that enable two different companies to exchange data
electronically using a network
- ERP systems: a large, integrated application that
is used by all of a company’s departments (manufacturing, sales, marketing,
distribution, customer service, etc.)
Design and Manufacturing
Systems include
- Computer-aided design (CAD): an application used
to design products electronically
- Computer-aided manufacturing (CAM): used to help
manage manufacturing operations and control the machinery used in those
processes.
- Robotics: devices controlled by a person or
computer that can react to sensory input
System development is the
process of planning, building, and maintaining a system. For most large and medium-sized companies,
information system development is performed by the information technology (IT)
or information systems (IS) department.
The person overseeing this department is typically the chief information
officer (CIO).
Project managers are
typically either a system analyst or senior programmer. As the project lead, it is the responsibility
of the project manager to plan, design, build and implement a system that meets
time and cost budgets while also meeting the predetermined system requirements.
There are many different job
functions within an IT department. Pg 485
lists some typical IT job titles. If you
become a computer professional, you will likely hold one of these positions.
Outsourcing:If
a company does not have enough people or employees with the right expertise, it
often outsources. Outsourcing is when a
company contracts with an outside vendor for all or part of its IT
functions.
·
Companies outsource when they feel an outsourcing vendor can do the job
cheaper and/or better than they can.
·
Reasons for the increased use of outsourcing by US firms include: high
domestic wages/ overhead, low international wages/overhead, improved WAN
technology, and flexible staffing options.
·
Disadvantages of outsourcing are potential conflict between employees
and outsourcing personnel, time zone differences, cultural differences,
language barriers, control and security, and less verbal communication.
There are two reasons why
companies build new computer systems:
- To fix a problem
- To gain a strategic advantage over their
competitors
The System Development Life
Cycle (SDLC) is an organized sequence of steps used to develop an information
system (pg 489). It begins with the
initial request for a new system and ends when the new system is fully
operational and problem-free. The six
phases of the SDLC are:
- Preliminary Investigation
- Analysis
- Design
- Acquisition
- Implementation
- Maintenance
A brief summary of the
primary tasks that occur in each step of the SDLC is given below:
Preliminary Investigation: In this phase you
- define the problems with the current system (or
define the business opportunity)
- develop possible solutions
- estimate the costs and benefits of the proposed
solutions
- create a feasibility reportthat summarizes the
data collected and gives a recommendation whether or not the project
should move forward
Systems Analysis: In this phase you gather detailed information about
the current system, analyze the collected data, and identify the requirements
for the new system.
- Information about the current system is collected
through interviews, questionnaires, organizational charts, and personal
observation.
- Analysis tools such as entity-relationship
diagrams, data flow diagrams, and use case diagrams are used to model the
current system.
- System requirements (determining exactly what the
new system must do) are gathered primarily through interviews with
management, the IT staff, and end users.
Factors that must be considered when developing system requirements
include input, output, processing, storage, and security.
System Design: In this phase:
- You specify the type of HW, SW, and network
components that will be needed by the new system.
- New applications are designed using program
flowcharts, pseudocode, structure charts, and/or data modeling.
- A network model indicating the locations of
networking devices is created.
- The overall structure of the database is designed
- The design phase is where the project team
designs a system to meet the system requirements identified in the
analysis phase.
- A cost-benefit analysis is performed to determine
if the project should move onto the acquisition phase
System Acquisition: In this phase:
- You decide whether to "make or buy" new
software needed by the system.
- Request for proposals are made to vendors and
vendor bids are evaluated.
- You purchase the new HW and/or software from the
vendor(s) you have chosen
Implementation: In this phase:
- the new system is put into place using one of the
following four system changeover methods: direct, parallel, phased, or
pilot.
- new programs, data files, and databases are
installed on the company’s production computers
- new HW is installed
- hardware and software testing is performed and
problem areas corrected
- users are trained
System Maintenance: In this phase
- existing software is modified
- new hardware and software are purchased to update
the system
- correcting any hardware and software problems
that occur
- security policies and procedures are followed to
keep the system secure
- user support is provided either in-house or
through a third-party company
There are many approaches to
systems development. You are expected to
know the traditional (SDLC) approach and the prototype approach.
- The traditional approach uses the six-step SDLC
discussed above. It is time
consuming and can be quite costly, but is widely considered the best way
to build an effective system.
- With prototyping, a small model of the overall
system is built and presented to users for enhancements. Based upon user’s input, the prototype
model is developed further and brought back to the users for further
enhancements. This process
continues until no more enhancements are needed. At this point, the prototype becomes the
finished system or the prototype becomes the model that is used to finish
building the system. The prototype
approach is often used when the users are unsure of the system
requirements or when the system must be developed very quickly.
0 comments:
Post a Comment