Transcript SYSTEM INTERDEPENDENCE

Chapter 2
Hardware and Software
SYSTEM INTERDEPENDENCE
INTERDEPENDENCE
HARDWARE
BUSINESS
SOFTWARE
DATABASE
Strategy
Rules
Procedures
ORGANIZATION
TELECOMMUNICATIONS
INFORMATION SYSTEM
Principles and Learning Objectives
• Computer hardware must be carefully selected to
meet the evolving needs of the organization and its
supporting information systems
– Identify and discuss the role of the essential
hardware components of a computer system
– Identify the characteristics of and discuss the usage
of various classes of single-user and multiuser
computer systems
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Principles and Learning Objectives
(continued)
• Systems and application software are critical in
helping individuals and organizations achieve their
goals
– Identify and briefly describe the functions of the two
basic kinds of software
– Outline the role of the operating system and
identify the features of several popular operating
systems
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Principles and Learning Objectives
(continued)
• Organizations should not develop proprietary
application software unless doing so will meet a
compelling business need that can provide a
competitive advantage
– Discuss how application software can support
personal, workgroup, and enterprise business
objectives
– Identify three basic approaches to developing
application software and discuss the pros and cons
of each
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Principles and Learning Objectives
(continued)
• Organizations should choose a programming
language whose functional characteristics are
appropriate for the task at hand, considering the
skills and experience of the programming staff
– Outline the overall evolution and importance of
programming languages and clearly differentiate
among the generations of programming
languages
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Principles and Learning Objectives
(continued)
• The software industry continues to undergo
constant change; users need to be aware of recent
trends and issues to be effective in their business
and personal life
– Identify several key software issues and trends
that have an impact on organizations and individuals
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Computer Systems: Integrating the
Power of Technology
• To assemble an effective and efficient system:
– Select and organize components while
understanding the trade-offs between overall system
performance and cost, control, and complexity
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Decisions about hardware focus on
three interrelated factors:
• capability (power and appropriateness for the task),
• speed, and
• cost.
Hardware Components
• Central processing unit (CPU)
– Arithmetic/logic unit (ALU)
• Performs calculations and makes logical comparisons
– Control unit
• Sequentially accesses, decodes and coordinates data
in CPU and other devices
• Primary memory
– Holds program instructions
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Hardware Components (continued)
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Processing and Memory Devices:
Power, Speed, and Capacity
• 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
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Processing Characteristics and
Functions
• Clock speed
– Produces a series of electronic pulses produced at a
predetermined rate that affects machine cycle time
• Physical characteristics of the CPU
– CPU speed is also limited by physical constraints
– To turn a digital circuit on or off, electrical current
flows through silicon
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Memory Characteristics and Functions
• Storage capacity
– Data is stored in memory as a combination of on or
off circuit states
– Eight bits together form a byte (B)
• Types of memory
– Random access memory (RAM)
• Temporary and volatile
– Read-only memory (ROM)
• Usually nonvolatile
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Computer Cycle Time
•
•
•
•
Millisecond - one thousandth of one second
Microsecond - one millionth of one second
Nanosecond - one billionth of one second
Picosecond - one trillionth of one second
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Clock Speed
• Internal Clock - CPU clock produces electronic
pulses at a predetermined rate.
• Clock speed - (usually) the time to retrieve an
instruction from memory and put it in a CPU
register
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Clock Speed
O.J.
• One Hertz (1 Hz) - one cycle per second.
• One Megahertz ( 1 MHz = 1,000,000 Hz) computer clock speed is measured in MHz.
• The clock speed for PCs ranges from about 20 MHz
to 4 GHz +.
NOTE: Machine cycle = Clock Speed
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Other measures of computer speed
•
•
•
•
MIPS - millions of instructions per second
Flop - floating point operation
Megaflops - millions of floating-point operations per second
Gigaflops - billions of floating-point operations per second
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Multiprocessing
• Multicore microprocessor
– Shares workload among two or more independent
processors in a single computer
• Parallel processing
– Speeds processing by linking several processors to
operate at the same time, or in parallel
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Multiprocessing (continued)
• Grid computing
– Collection of computers working to solve a common
problem
• Cloud computing
– Giant cluster of computers serving as a host to run
applications that require high-performance
computing
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Secondary Storage and Input and
Output Devices
• Secondary storage
–
–
–
–
Also called permanent storage
Nonvolatile
Greater capacity and greater economy than memory
Costs considerably less per megabyte of capacity
than SDRAM
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Access Methods
• Sequential access
– Data must be accessed in the order in which it is
stored
• Direct access
– Data can be retrieved directly, without having to
pass by other data in sequence
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Secondary Storage Devices
• Magnetic tapes
– Secondary storage used primarily for backups
• Magnetic disks
– Direct access secondary storage, e.g., hard disk
• RAID
– Method of storing data so that if a hard drive fails,
the lost data on that drive can be rebuilt
• SAN
– Provides high-speed connections between data
storage devices and computers over a network
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Secondary Storage Devices
(continued)
• Optical disks
– Compact disc read-only memory (CD-ROM) with a
storage capacity of 740 MB of data
• Digital video disk (DVD)
– Used to store digital video or computer data
• Flash memory
– Nonvolatile silicon computer chip
– Keeps its memory when the power is shut off
Volatile versus Non-Volatile
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Input Devices
• Personal computer input devices
– Keyboard, mouse
• Speech-recognition technology
– Input devices that recognize human speech
• Digital cameras
– Record and store images or video in digital form
• Touch-sensitive screens
– Allow display screens to function as input as well as
output devices
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Input Devices (continued)
• Optical data readers
– Used to scan documents
• Magnetic ink character recognition (MICR) devices
– System that reads data quickly
• Pen input devices
– Touching the screen with a pen input device allows
you to activate a command
• Radio Frequency Identification
– Transmits data by a mobile device, called a tag
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Output Devices
• Display monitors (CRTs)
– TV-screen-like device on which output from the
computer is displayed
• 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
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Output Devices (continued)
• Printers and plotters
– Laser printers are generally faster than inkjet printers
and can handle more volume
• Digital audio player
– Stores, organizes, and plays digital music files
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Computer System Types
• Handheld computers
– Single-user computers that provide ease of
portability
• Ultra laptop computer
– Weighs less than three pounds (1.4 kg)
– Usually targeted for use by business travelers
• Portable computers
– Computer small enough to be carried easily
• Thin client
– Low-cost, centrally managed computer with no extra
drives
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Computer System Types (continued)
• Desktop computers
– Small, inexpensive single-user computer systems
that are highly versatile
• Workstations
– More powerful than personal computers but small
enough to fit on a desktop
• Servers
– Computers designed for a specific task
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Computer System Types (continued)
• Mainframe computer
– Large, powerful computer shared by hundreds of
concurrent users
• Supercomputers
– Most powerful computer systems
– Has fastest processing speeds and highest
performance
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Overview of Software
• 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
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Supporting Individual, Group, and
Organizational Goals
• Sphere of influence
– The scope of problems and opportunities addressed by
a particular organization
• Workgroup
– Two or more people who work together to achieve a
common goal
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Supporting Individual, Group, and
Organizational Goals (continued)
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Installing and Removing New Software
• Installing new software usually involves only a few
setup steps
• When possible remove software using an
add/remove software utility
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Systems Software
• Critical function of systems software
– Controlling operations of computer hardware
• Systems software
– Supports the application programs’ problem-solving
capabilities
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Operating Systems
• Combinations of OSs, computers, and users
–
–
–
–
Single computer with a single user
Single computer with multiple users
Multiple computers
Special-purpose computers
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Operating Systems (continued)
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Operating Systems (continued)
• Activities performed by the operating system
include:
– Perform common computer hardware functions
– Provide a user interface and input/output
management
– Provide a degree of hardware independence
– Manage system memory
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Operating Systems (continued)
• Common hardware functions
– OS acts as an intermediary between the application
and the hardware
• User interface and input/output management
– User interface allows people to access and
command the computer system
• Hardware independence
– Programmers can use APIs to create application
software
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OS Tasks: User Interface Controls
• Command interface
– blank screen; users type text commands for the computer to
perform basic functions.
• Menu interface
– selection menu; users select from menu options.
• Graphical user interface (GUI)
– graphics screen; users select graphical pictures (icons).
– Operating system shells - program containing a menu or
graphical user interface between the OS and user.
Social interface. A user interface that guides the user through
computer applications by using cartoonlike characters, graphics, animation,
and voice commands.
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Operating Systems (continued)
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Operating Systems (continued)
• Memory management
– OS controls how memory is accessed and
maximizes available memory and storage
• Processing tasks
– Task management allocates computer resources
• Networking capability
– Computers can join together in a network to send
and receive data
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Operating Systems (continued)
• Access to system resources and security
– OS needs to provide a high level of security against
unauthorized access to users’ data
• File management
– OS manages files to ensure that files in secondary
storage are available when needed
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Current Operating Systems
• Microsoft PC operating systems
– Windows Vista released in 2007 with the goal of
providing a more secure and stable operating
system
• Apple computer operating systems
– OSs have evolved and often provide features not
available from Microsoft
• Linux
– An open-source operating system
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Current Operating Systems
(continued)
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Workgroup Operating Systems
•
•
•
•
•
Windows Server
UNIX
NetWare
Red Hat Linux
Mac OS X Server
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Enterprise Operating Systems
• z/OS
– IBM’s first 64-bit enterprise OS
• HP-UX and Linux
– Robust UNIX-based OS
– Supports Internet database
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Operating Systems for Small
Computers, Embedded
Computers, and Special-Purpose
Devices
• Palm OS
– Operating system used in over 30 million handheld
computers and smartphones
• Windows Embedded
– Family of Microsoft OSs embedded into small
computer devices
• Windows Mobile
– Operating system designed for smartphones and
PDAs
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Utility Programs
• Help to perform maintenance or correct problems
with a computer system
• Help to secure and safeguard data
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Utility Programs (continued)
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Application Software
• Give users the ability to solve problems and
perform specific tasks
• Interact with systems software
– Systems software then directs the hardware to
perform tasks
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Types and Functions of Application
Software
• Proprietary software
– One-of-a-kind program for a specific application
• Off-the-shelf software
– Existing software program that can be purchased
• Application service provider (ASP)
– Provides the software, support, and computer hardware
on which to run the software
• Software as a service (SaaS)
– Businesses subscribe to Web-delivered business
application software by paying a monthly service charge
or a per-use fee
• Open Source software
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Types and Functions of Application
Software (continued)
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Types and Functions of Application
Software (continued)
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Personal Application Software
•
•
•
•
•
•
Word Processing
Spreadsheet Analysis
Database Applications
Graphics Programs
Personal Information Managers
Software Suites and Integrated Software Packages
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Personal Application Software
(continued)
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Workgroup Application Software
• Workgroup application software
– Designed to support teamwork
• Groupware
– Helps groups of people work together effectively
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Workgroup Application Software
(continued)
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Enterprise Application Software
• 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
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Enterprise Application Software
(continued)
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Application Software for Information,
Decision Support, and Specialized
Purposes
• Available in every industry
– Example: Genetic researchers are using software to
visualize and analyze the human genome
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Programming Languages
• Sets of symbols and rules used to write program
code
• Programming
– Translating what a user wants into instructions that
the computer can understand and execute
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Programming Languages (continued)
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Software Issues and Trends
• Software issues
– Software bugs
– Copyrights and licenses
– Global software support
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Software Bugs
• Defects in a computer program that keeps it from
performing as it is designed to perform
• Tips for reducing impact of software
– Register all software so that you can receive bug
alerts, fixes, and patches
– Check the manual or read-me files for work-arounds
– Access support area of the manufacturer’s Web site
for patches
– Install the latest software updates
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Copyrights and Licenses
• Most software products
– Protected by law using copyright or licensing
provisions
• Some software
– Require that you register or activate it before it can
be fully used
•
(work for hire)
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Software Upgrades
• Software companies
– Periodically revise their programs and sell new
versions
• Software upgrades
– Usually cost much less than the original purchase
price
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Global Software Support
• Supporting local operations
– Biggest challenge faced by IS teams when putting
together standardized, companywide systems
• In today’s computer systems
– Software is an increasingly critical component
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Summary
• Hardware devices
– Work together to perform input, processing, data
storage, and output
• Computer systems
– Can store large amounts of data and instructions in
secondary storage
• Input and output devices
– Allow users to provide data and instructions to the
computer for processing, storage, and output
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Summary (continued)
• Operating system (OS)
– Set of computer programs that controls the computer hardware to support users’
computing needs
• Application software
– Applies the power of the computer to solve problems and perform specific tasks
• Approaches to developing application software
– Build proprietary application software
– Buy existing programs off the shelf
– Combination of customized and off-the-shelf
• Programming languages
– Provide instructions to a computer to perform some processing activity
• Software issues and trends
– Software bugs, software licensing and copyrighting, software
upgrades, and global software support
• Global software support
– Important consideration for large, global companies putting together
standardized, company-wide systems
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