Computer information mft review
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Transcript of Computer information mft review
Material fromFundamentals of Information Systems,
Fourth EditionBy
Ralph Stair and George Reynolds
1
Basics of Information Systems
Information Concepts: Data, Information, and
Knowledge
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• Data: raw facts– Alphanumeric, image, audio, and video
• Information: collection of facts organized in such a way that they have additional value beyond the value of the facts themselves–Value of Information is directly linked
to how it helps decision makers achieve their organization’s goals and can be measured• in time required to make a decision• Increased profits to the company
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Figure 1.2: The Process of Transforming Data into Information
Data, Information, and Knowledge
The Characteristics of Valuable Information
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Table 1.2: Characteristics of Valuable Information
The Characteristics of Valuable Information (continued)
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Table 1.2: Characteristics of Valuable Information (continued)
What Is an Information System?
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Figure 1.3: The Components of any Information System
Computer-Based Information Systems
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Computer-based information system (CBIS): single set of hardware, software, databases, telecommunications, people, and procedures configured to collect, manipulate, store, and process data into information
Computer-Based Information Systems
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• CBIS components– Hardware: computer equipment used to
perform input, processing, and output activities– Software: computer programs that govern the
operation of the computer– Database: organized collection of facts and
information– Telecommunications: electronic transmission of
signals for communications– Networks: connect computers and equipment
in a building, around the country, and around the world
Business Information Systems
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Most common types of information systems used in business organizationsElectronic and mobile commerce systemsTransaction processing systemsManagement information systemsDecision support systemsSpecialized business information systems
Electronic and Mobile Commerce
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E-commerce: any business transaction executed electronically between partiesCompanies (B2B)Companies and consumers (B2C)Consumers and other consumers (C2C)Companies and the public sectorConsumers and the public sector
Transaction Processing Systems
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Transaction: business-related exchangePayments to employeesSales to customersPayments to suppliers
Transaction processing system (TPS): organized collection of people, procedures, software, databases, and devices used to record completed business transactions
Additional Business Information Systems
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• Management Information Systems (MIS)– provide routine information to managers and
decision makers• Knowledge Management Systems (KMS)
– create, store, share, and use the organization’s knowledge and experience
• Artificial intelligence (AI)– field in which the computer system takes on the
characteristics of human intelligence• Decision support system (DSS)
– used to support problem-specific decision making
Hardware and Software Basics
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Hardware Components
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• Central processing unit (CPU)– Arithmetic/logic unit (ALU): performs
calculations and makes logical comparisons– Control unit: accesses, decodes and
coordinates data in CPU and other devices• Primary memory: holds program
instructions and data for processing • Secondary storage: more permanent
storage• Input and output devices• Communications devices
Hardware Components (continued)
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Figure 2.1: Hardware Components
Processing and Memory Devices: Power and Speed
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• System unit– Houses the components responsible for
processing (the CPU and memory) – All other computer system devices are linked
either directly or indirectly into the system unit housing
• Clock speed– series of electronic pulses produced at a
predetermined rate that affects machine cycle time
– Clock speed is often measured in megahertz (MHz) for millions or gigahertz(GHz) for billions of cycles per second
Memory and Storage Characteristics and Functions
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• Types of Memory – Random access memory (RAM)
• Temporary• Volatile
– Read-only memory (ROM)• Usually nonvolatile
• Secondary storage– Also called permanent storage– Nonvolatile– Greater capacity and greater economy than memory– Measured in bytes: kilo, mega, giga, tera– Different access methods
• Sequential access: data must be accessed in the order in which it is stored– Sequential access storage devices (SASDs)
• Direct access: data can be retrieved in any order– Direct access storage devices (DASDs)
Secondary Storage Devices
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• Magnetic tapes– Secondary storage used primarily for backups
• Magnetic disks– Direct access secondary storage, e.g., hard disk
• RAID– Stores extra bits so that data can be reconstructed if
system fails• SAN• Provides high-speed connections between data
storage devices and computers over a network Optical disks– Direct access optical disc, e.g., CD-ROM
• Digital video disk (DVD)– Stores several gigabytes of data
• Flash memory– Nonvolatile silicon computer chip
Input Devices
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• Personal computer input devices– Keyboard, mouse
• Speech-recognition technology– Input devices that recognize human speech
• Digital cameras– Input device used with PC to record/store images in digital form
• Terminals– Input and display devices that perform data entry and input at the same
time• Touch-sensitive screens
– Allow display screens to act as input devices as well as output devices• Bar-code scanners
– Employs a laser scanner to read a bar-coded label• Magnetic ink character recognition (MICR) devices• Code data on banking forms, such as checks Pen input devices
– Activate a command, enter handwritten notes, and draw objects• Radio Frequency Identification (RFID)
– Employs a microchip with an antenna to broadcast its unique identifier and location to a receiver
Output Devices
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• Display monitors (CRTs)– Output quality measured by number of pixels and dot
pitch• Liquid crystal displays (LCDs)
– Easier on eyes, use less electricity, take up less space than CRTs
• Organic light-emitting diodes (OLEDs)– Directly emits light rather than using backlight
• Sharper colors and thinner displays Printers and plotters: hard copy output– Printers: laser, inkjet – Plotters: used for general design work
• Digital audio player– Stores, organizes, and plays digital music files
Overview of Software
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• Computer programs: sequences of instructions for the computer
• Documentation: describes program functions
• Systems software: coordinates the activities of hardware and programs
• Application software: helps users solve particular problems
Systems Software
Application Software
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• Give users the ability to solve problems and perform specific tasks
• Interact with systems software; systems software then directs the hardware to perform tasks
• Proprietary software: unique program for a specific application, usually developed and owned by a single company
• Off-the-shelf software: existing software program that can be purchased
• Customized package
Personal Application Software
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Serves the needs of an individual userIncludes personal productivity software
Enables users to improve their personal effectiveness
Personal Application Software (continued)
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Table 2.7: Examples of Personal Productivity Software
Personal Application Software (continued)
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Table 2.7: Examples of Personal Productivity Software (continued)
Workgroup Application Software
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Workgroup application software: support teamwork, whether people are in the same location or dispersed around the world
Groupware: software that helps groups of people work together more efficiently and effectively
Enterprise Application Software
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Software that benefits an entire organization
Enterprise resource planning (ERP) software: programs that manage a company’s vital business operations for an entire multisite, global organization
Enterprise Application Software (continued)
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Table 2.10: Examples of Enterprise Application Software
Information, Decision Support,and Specialized Software
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Used in businesses of all sizes and types to increase profits or reduce costs
Available in every industryExample: analysis to increase the cure rate for
cancer
Data Management
Data Management
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Without data and the ability to process it, an organization could not successfully complete most business activities
Data consists of raw factsFor data to be transformed into useful
information, it must first be organized in a meaningful way
The Hierarchy of Data
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• Bit (a binary digit): a circuit that is either on or off• Byte: eight bits• Character: basic building block of information
– Each byte represents a character – Can be an uppercase letter, lowercase letter, numeric
digit, or special symbol• Field: typically a name, number, or combination
of characters that describes an aspect of a business object or activityRecord: a collection of related data fields
• File: a collection of related records• Database: a collection of integrated and related
files• Hierarchy of data: bits, characters, fields,
records, files, and databases
The Hierarchy of Data
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Figure 3.1: The Hierarchy of Data
Data Entities, Attributes, and Keys
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• Entity: a generalized class of people, places, or things (objects) for which data is collected, stored, and maintained
• Attribute: characteristic of an entity • Data item: value of an attribute• Key: field or set of fields in a record that is
used to identify the record• Primary key: field or set of fields that
uniquely identifies the record
Data Entities, Attributes, and Keys
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Figure 3.2: Keys and Attributes
The Database Approach
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• Traditional approach to database management– separate data files are created for each
application• Results in data redundancy (duplication)• Data redundancy conflicts with data integrity
• Database approach to database management:– pool of related data is shared by multiple
applications• Significant advantages over traditional approach
The Database Approach to Data Management
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Figure 3.3: The Database Approach to Data Management
The Database Approach Advantages
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Table 3.1: Advantages of the Database Approach
The Database Approach (continued)
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Table 3.1: Advantages of the Database Approach (continued)
The Database Approach Disadvantages
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Table 3.2: Disadvantages of the Database Approach
Data Modeling and the Relational Database Model
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When building a database, consider:Content: What data should be collected, at
what cost?Access: What data should be provided to
which users and when?Logical structure: How should data be
arranged to make sense to a given user?Physical organization: Where should data be
physically located?
Data Modeling
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• Building a database requires two types of designs– Logical design
• Abstract model of how data should be structured and arranged to meet an organization’s information needs– Data model: a diagram of data entities and their
relationships– Entity-relationship (ER) diagrams: data models
that use basic graphical symbols to show the organization of and relationships between data
– Physical design• Fine-tunes the logical database design for
performance and cost considerations
ER diagram for a Customer Order Database
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ER diagram Showing the Relationship between the Manager, Department and
Project
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Implementing the Relational Database Model
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data elements are placed in two-dimensional tables (relations), which are the logical equivalent of files
Each row of a table represents a data entityColumns of the table represent attributesThe domain of the database model consists
of all of the allowable values for data attributes i
The Relational Database Model
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Figure 3.5: A Relational Database Model
Manipulating Databases
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Selecting: eliminates rows according to criteria
Projecting: eliminates columns in a tableJoining: combines two or more tablesLinking: relates or links two or more tables
using common data attributes
Manipulating Data (continued)
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Figure 3.7: Linking Data Tables to Answer an Inquiry
Database Management Systems (DBMS)
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• Interface between:– Database and application programs – Database and the user
• Creating and implementing the right database system ensures that the database will support both business activities and goals
• DBMS: a group of programs used as an interface between a database and application programs or a database and the user
Overview of Database Types
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• Flat file– Simple database program whose records have
no relationship to one another• Single user
– Only one person can use the database at a time
– Examples: Access, FileMaker, and InfoPath• Multiple user
– Allows dozens or hundreds of people to access the same database system at the same time
– Examples: Oracle, Sybase, and IBM
Distributed Databases
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Distributed databaseData may be spread across several smaller
databases connected via telecommunications devices
Corporations get more flexibility in how databases are organized and used
Replicated databaseHolds a duplicate set of frequently used data
Telecommunications
Basic Concepts of Telecommunications
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• Telecommunications: electronic transmission of signals for communications
• Computer network: communications media, devices, and software needed to connect two or more computer systems or devices
• Network types: personal area network (PAN), local area network (LAN), metropolitan area network (MAN), wide area network (WAN), and international networks
The Internet
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Internet: collection of interconnected networks, all freely exchanging information
Internet Protocol (IP): communication standard that enables traffic to be routed from one network to another as needed
Uniform Resource Locator (URL): an assigned address on the Internet for each computer
Business Networks
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Intranet: internal corporate network built using Internet and World Wide Web standards and protocols
Extranet: network based on Web technologies that links selected resources of a company’s intranet with its customers, suppliers, or other business partners
Systems Development
An Overview of Systems Development
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Managers and employees in all functional areas work together in a business information system
Users help and often lead the way with development process
Participants in systems development: Determine when a project failsAre critical to systems development success
Participants in Systems Development
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• Development team consists of the following:– Project managers: coordinate system
development effort– Stakeholders: directly or indirectly benefit from
the project– Users: interact with the system regularly– Systems analysts: analyze and design business
systems– Programmers: modify or develop programs to
satisfy user requirements– Various support personnel: specialists, vendors
Information Systems Planning and Aligning Corporate and IS
Goals
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Information systems planning: translating strategic and organizational goals into systems development initiatives
Aligning organizational goals and IS goals is critical for any successful systems development effort
Determining whether organizational and IS goals are aligned can be difficult
Information Systems Planning and Aligning Corporate and IS Goals (continued)
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Figure 8.2: Information Systems Planning
Systems Development Life Cycles
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• The systems development process is also called a systems development life cycle (SDLC)
• Common SDLCs– Prototyping– Rapid application development (RAD) Systems
• development approach that employs tools, techniques, and methodologies designed to speed application development
– End-user development any systems • development project in which the primary effort is
undertaken by a combination of business managers and users
Systems Development Activities
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• Systems investigation:– problems and opportunities are identified and considered
in light of the goals of the business• Systems analysis:
– study of existing systems and work processes to identify strengths, weaknesses, and opportunities for improvement
• Systems design: – defines how the information system will do what it must
do to obtain the problem solution• Systems implementation:
– creation or acquisition of various system components detailed in the systems design, assembling them, and placing the new or modified system into operation
• Systems maintenance and review: – ensures that the system operates as intended and
modifies the system so that it continues to meet changing business needs