Fundamentals of Information Systems, Sixth Edition
Chapter 3
Hardware and Software
Hardware Components
• Central processing unit (CPU):
– Arithmetic/logic unit, the control unit, and the register areas
• Arithmetic/logic unit (ALU):
– Performs mathematical calculations and makes logical comparisons
• Control unit:
– Sequentially accesses program instructions,
decodes them, and coordinates the flow of data in and out of the ALU, registers, primary storage, and even secondary storage and various output devices
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
Processing Characteristics and Functions
• Clock speed:
– Series of electronic pulses produced at a
predetermined rate that affects machine cycle time – Often measured in:
• Megahertz (MHz): millions of cycles per second
• Gigahertz (GHz): billions of cycles per second
• Physical characteristics of the CPU
– Most CPUs are collections of digital circuits
imprinted on silicon wafers, or chips, each no bigger than the tip of a pencil eraser
Memory Characteristics and Functions
• Memory:
– Provides the CPU with a working storage area for programs and data
– Rapidly provides data and instructions to the CPU
• Storage capacity:
– Eight bits together form a byte (B)
Memory Characteristics and Functions
(continued)
Memory Characteristics and Functions (continued)
• Types of memory:
– Random access memory (RAM):
• Temporary and volatile
– Read-only memory (ROM):
• Nonvolatile
• Provides permanent storage for data and instructions that do not change
Multiprocessing
• Multiprocessing:
– Simultaneous execution of two or more instructions at the same time
• Multicore microprocessor:
– Combines two or more independent processors into a single computer
Multiprocessing (continued)
• Parallel computing:
– Simultaneous execution of the same task on multiple processors to obtain results faster
• Grid computing:
– Use of a collection of computers to work in a
coordinated manner to solve a common problem
Secondary Storage and Input and Output Devices
• Secondary storage:
– Compared with memory, offers the advantages of nonvolatility, greater capacity, and greater economy – Considerably slower than memory
Access Methods
• Sequential access:
– Data must be retrieved in the order in which it is stored
– Devices used called sequential access storage devices (SASDs)
• Direct access:
– Records can be retrieved in any order
– Devices used are called direct access storage devices (DASDs)
Secondary Storage Devices
• Magnetic tapes:
– Primarily for storing backups of critical organizational data
• Magnetic disks:
– Direct-access storage device
• Redundant array of independent/inexpensive disks (RAID):
– Method of storing data that generates extra bits of data from existing data
• Virtual tape:
– Storage technology for less frequently needed data
Secondary Storage Devices (continued)
• Storage area network:
– Uses computer servers, distributed storage devices, and networks to tie everything together
• Optical discs:
– Common form of optical disc on which data cannot be modified once it has been recorded
• Digital video disc (DVD):
– Storage medium used to store software, video games, and movies
Secondary Storage Devices (continued)
• Solid state secondary storage devices:
– Store data in memory chips rather than magnetic or optical media
– Have few moving parts, so they are less fragile than hard disk drives
– Disadvantages of SSD:
• High cost per GB of data storage
• Lower capacity compared to current hard drives
Input Devices
• Devices used to input general types of data:
– Personal computer input devices – Speech recognition technology – Digital cameras
– Touch-sensitive screens – Optical data readers
– Magnetic ink character recognition (MICR) devices – Pen input devices
– Magnetic stripe card
– Radio Frequency Identification
Output Devices
• Display monitors:
– Used to display the output from the computer – Plasma display:
• Uses thousands of smart cells (pixels) consisting of electrodes and neon and xenon gases that are
electrically turned into plasma to emit light
– LCD displays:
• Flat displays that use liquid crystals
– Organic light-emitting diodes (OLEDs):
• Use a layer of organic material sandwiched between two conductors
Output Devices (continued)
• Printers and plotters:
– Two main types of printers are laser printers and inkjet printers
– Plotters are a type of hard-copy output device used for general design work
• Digital audio player:
– Can store, organize, and play digital music files
• E-books:
– Digital media equivalent of a conventional printed book
Computer System Types
• Computer systems:
– Can range from desktop (or smaller) portable
computers to massive supercomputers that require housing in large rooms
Computer System Types (continued)
Computer System Types (continued)
Portable Computers
• Handheld computers:
– Single-user computers that provide ease of portability because of their small size
• Laptop computer:
– Personal computer designed for use by mobile users
• Notebook computers:
– Lightweight computer that weighs less than 5 pounds
Portable Computers (continued)
• Netbook computer:
– The smallest, lightest, least expensive member of the laptop computer family
• Tablet computers:
– Portable, lightweight computers with no keyboard
• Smartphone:
– Combines the functionality of a mobile phone,
camera, Web browser, e-mail tool, MP3 player, and other devices
Nonportable Single-User Computers
• Thin client:
– Low-cost, centrally managed computer with no extra drives
• Desktop computers:
– Single-user computer systems that are highly versatile
Nonportable Single-User Computers (continued)
• Nettop computer:
– Inexpensive desktop computer designed to be
smaller, lighter, and consume much less power than a traditional desktop computer
• Workstations:
– More powerful than personal computers but still small enough to fit on a desktop
Multiple-User Computer Systems
• Server:
– Used by many users to perform a specific task, such as running network or Internet applications
• Blade server:
– Houses many computer motherboards
– The approach requires much less physical space than traditional server farms
Multiple-User Computer Systems (continued)
• Mainframe computer:
– Large, powerful computer shared by hundreds of concurrent users connected to the machine over a network
• Supercomputers:
– The most powerful computers with the fastest processing speed and highest performance
Overview of Software
• Computer programs:
– Sequences of instructions for the computer
• Documentation:
– Describes program functions to help the user operate the computer system
• Types of software:
– Systems software – Application software
Installing and Removing New Software
• Before you can use any type of software, it must be installed on a computer
• Software for personal computers typically comes
on CDs or is downloaded from the Web
Systems Software
• Includes:
– Operating systems – Utility programs
Operating Systems
• Set of programs that controls computer hardware and acts as an interface with application programs
• Can control one computer or multiple computers, or
• Can allow multiple users to interact with one computer
• Combinations of OSs, computers, and users:
– Single computer with a single user – Single computer with multiple users – Multiple computers with multiple users – Special-purpose computers
Operating Systems (continued)
Operating Systems (continued)
• Activities performed by the operating system:
– Perform common computer hardware functions – Provide a user interface and input/output
management
– Provide a degree of hardware independence – Manage system memory
– Manage processing tasks
– Provide networking capability
– Control access to system resources – Manage files
Operating Systems (continued)
• Common hardware functions:
– Get input from keyboard or another input device – Retrieve data from disks
– Store data on disks
– Display information on a monitor or printer
Operating Systems (continued)
• User interface and input/output management:
– User interface:
• Allows individuals to access and command the computer system
– Command-based user interface:
• Requires that text commands be given to the computer to perform basic activities
– Graphical user interface (GUI):
• Uses icons and menus displayed on screen to send commands to the computer system
Operating Systems (continued)
• Hardware independence:
– Application program interface (API):
• Allows applications to make use of the operating system
• Memory management:
– Allows computer to execute program instructions effectively and to speed processing
Operating Systems (continued)
• Processing tasks:
– Multitasking:
• More than one program can run at the same time
– Time-sharing:
• Allows more than one person to use a computer system at the same time
Operating Systems (continued)
Operating Systems (continued)
• Networking capability:
– Allows computers in a network to send and receive data and share computing resources
• Access to system resources and security:
– Protection against unauthorized access – OS establishes a logon procedure
• File management:
– Ensures that files in secondary storage are available when needed and that they are protected from
access by unauthorized users
Current Operating Systems
• Microsoft PC operating systems:
– Windows XP – Windows Vista – Windows 7
• Apple computer operating systems:
– Wintel
– Snow Leopard (OS X v10.6)
• Linux:
– Red Hat Linux
– Caldera OpenLinux
Utility Programs
• Help to perform maintenance or correct problems with a computer system
• Some can help computer systems run better and longer without problems
• Can help to secure and safeguard data
Application Software
• Application programs:
– Interact with systems software
– Help you perform common tasks, such as:
• Creating and formatting text documents
• Performing calculations
• Managing information
Personal Application Software
• Word processing
• Spreadsheet analysis
• Database applications
• Graphics program
• Personal information managers
• Software suites and integrated software packages
Mobile Application Software
• Operating systems designed for smartphones include:
– OS X iPhone, Android, and WebOS
• Tens of thousands of applications have been:
– Developed by third parties for the iPhone
• Palm WebOS:
– Has only recently released its software development kit
Enterprise Application Software
• Software that benefits an entire organization
• Enterprise resource planning (ERP) software:
– Set of integrated programs that manage a
company’s vital business operations for an entire multisite, global organization
Application Software for Information, Decision Support, and Specialized
Purposes
• Available in every industry:
– Specialized application software for information, decision support, and other purposes
Programming Languages
• Sets of keywords, symbols, and a system of rules for constructing statements:
– By which humans can communicate instructions to be executed by a computer
• Programming:
– Involves translating what a user wants to accomplish into instructions that the computer can understand and execute
Summary
• Hardware:
– The physical components of a computer that perform the input, processing, storage, and output activities of the computer
• Green computing:
– Concerned with the efficient and environmentally responsible design, manufacture, operation, and disposal of IS-related products
• Software:
– Consists of programs that control the workings of the computer hardware
Summary (continued)
• Operating system (OS):
– Set of computer programs that controls the computer hardware to support users’ computing needs
– Manages tasks to allocate computer resources through multitasking and time-sharing
• Application software:
– Applies the power of the computer to solve problems and perform specific tasks
