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Hardware: Input, Processing, and
Output Devices
Principles of Information Systems, Eighth Edition 2
Learning Objectives
1. Describe how to select and organize computer hardware components to support information system (IS) objectives and business needs
2. Describe the power, speed, and capacity of central processing and memory devices
3. Describe the access methods, capacity, and portability of secondary storage devices
4. Discuss the speed, functionality, and importance of input and output devices
5. Identify popular classes of computer systems and discuss the role of each
3
Why Learn About Hardware?
• Can improve productivity, increase revenue, reduce costs, and provide better service
• Managers are expected to know about hardware– To help define business needs– To ask questions and evaluate options when buying
equipment
4
Introduction
• Hardware: any machinery (most of which use digital circuits) that assists in the input, processing, storage, and output activities of an information system
• When making hardware decisions, businesses must consider how the hardware can support:– Objectives of the information system– Goals of the organization
Hardware Devices Analogy: A Paper-Based Office
5
Secondary Storage
Register Storage
Output
Primary Storage
Input
Principles of Information Systems, Eighth Edition6
Hardware Components
Hardware Components in Action
• Execution of machine-level instruction Phase 1 : Instruction Phase – Fetch and Decode Phase 2 : Execution Phase – Execute and Store
• I-time: the time taken to perform phase 1• E-time: the time taken to perform phase 2
Principles of Information Systems, Eighth Edition 7
Principles of Information Systems, Eighth Edition 8
Hardware Components in Action
Figure 3.2: Execution of an Instruction
Principles of Information Systems, Eighth Edition 9
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
Principles of Information Systems, Eighth Edition 10
Processing Characteristics and Functions
• Computer execute an instruction during a machine cycle
• Completing the instruction and execution phase – make up one machine cycle
• Machine cycle time is measured in:– Nanoseconds (1 billionth of a second)– Picoseconds (1 trillionth of a second)– MIPS (millions of instructions per second)
Principles of Information Systems, Eighth Edition 11
Processing Characteristics and Functions (continued)
• 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
• Microcode: predefined, elementary circuits and logical operations that the processor performs when it executes an instruction
Principles of Information Systems, Eighth Edition 12
Physical Characteristics of the CPU
• Collection of digital circuits on chips• Electrical current flows through silicon – to turn the
digital circuit on or off• Gordon Moore – former Intel’s chairman
hypothesised that progress in chip manufacturing: transistor density of chips will double every 18 months (Moore’s Law)
Principles of Information Systems, Eighth Edition 13
Physical Characteristics of the CPU (continued)
Figure 3.3: Moore’s Law
Principles of Information Systems, Eighth Edition 14
Memory Characteristics and Functions
• Main memory– Located physically close to the CPU, but not on the
CPU chip itself– Rapidly provides data and instructions to the CPU
Principles of Information Systems, Eighth Edition 15
Storage Capacity
Table 3.1: Computer Storage Units
Principles of Information Systems, Eighth Edition 16
Types of Memory
Figure 3.4: Basic Types of Memory Chips
Principles of Information Systems, Eighth Edition 17
Types of Memory (Cash Memory)
Figure 3.5: Cache Memory
Principles of Information Systems, Eighth Edition 18
Multiprocessing
• Multiprocessing: simultaneous execution of two or more instructions at the same time
• Multiprocessing using coprocessors– Coprocessor: speeds processing by executing
specific types of instructions while the CPU works on another processing activity
Principles of Information Systems, Eighth Edition 19
Parallel Computing
• Parallel computing: simultaneous execution of the same task on multiple processors to obtain results faster
• Massively parallel processing:– Speeds processing by linking hundreds or thousands
of processors to operate at the same time, or in parallel
– Each processor has its own bus, memory, disks, copy of the operating system, and applications
Principles of Information Systems, Eighth Edition 20
Parallel Computing (continued)
• 2 different approaches to achieving parallel computing– Single instruction/multiple data (SIMD) parallel
processors – Multiple instruction/multiple data (MIMD) parallel
processors• Grid computing: use of a collection of
computers, often owned by multiple individuals or organizations, to work in a coordinated manner to solve a common problem
Principles of Information Systems, Eighth Edition 21
Secondary Storage
• Permanent storage• Compared with memory, offers the advantages of
nonvolatility, greater capacity, and greater economy
• Selection of secondary storage : access methods, storage capacities, and portability required - determined by the information system’s objectives
• Example: credit card company
Principles of Information Systems, Eighth Edition 22
Access Methods
Two types of access methods• Sequential access: records must be retrieved in
order in which it’s stored– Devices used are called sequential access storage
devices (SASDs)• Direct access: records can be retrieved in any
order– Devices used are called direct access storage
devices (DASDs)
Principles of Information Systems, Eighth Edition 23
Devices• Magnetic tapes• Magnetic disks• Optical disks• Digital video disk (DVD)• Holographic Versatile Disc (HVD)• Memory cards• Flash memory• RAID • Virtual tape
Magnetic Tapes
Principles of Information Systems, Eighth Edition 24
• Sequential secondary storage medium
• Primarily for storing backups
• Tapes similar to audio and videocassettes
• Portion of tapes are magnetized to represent bits
Magnetic Disks
Principles of Information Systems, Eighth Edition 25
• Direct access storage medium
• e.g. diskette, hard disks
• Allows fast data retrieval
Optical Disc
Principles of Information Systems, Eighth Edition 26
• Data is recorded by special lasers that physically burn pits in the disk.
• Data accessed – optical disc device (compact disk player)
• e.g. CD-ROM – 740MB, CD-RW
DVD and HVD
Principles of Information Systems, Eighth Edition 27
• DVD (Digital Video Disc)• Looks like a CD but more storage
capacity ~ 135min of digital video.• Software, video games, movies
• HVD (Holographic Versatile Disc)• Advanced optical disk – ongoing
research• Hold 200GB of data• Write data 10 times faster than
DVD
Memory cards
Principles of Information Systems, Eighth Edition 28
• Functions as a hard disk drive
• Portable, relatively easy to use
• Need to use memory card reader/writer
Flash Memory
Principles of Information Systems, Eighth Edition 29
• A silicon computer chip• Keeps its memory when the power is
shut off• “Flash” – the memory cell is erased or
reprogrammed in a single action or flash
• e.g. – Migo – keychain device, comes with software that captures files and settings from e-mail, word processing, web browser, presentation programs.
RAID and Virtual Tape
• Storage technologies• RAID –
– Redundant array of independent /inexpensive disks– duplicate existing data on drives, provides exact copy,
store on different physical disk drives • Virtual Tape
– manages less frequently needed data– Move data to less costly storage media– Software – virtual tape server– Vendor – IBM and Storage Technology
Principles of Information Systems, Eighth Edition 30
Principles of Information Systems, Eighth Edition 31
Enterprise Storage Options
• Needs to store massive amount of data• 3 forms:
1. Attached storage tape, hard disks, optical devices Simple, cost effective - single users and small
groups Not allowed share storage
2. Network-attached storage (NAS) Storage devices attach to a network Users can share and access same information
Principles of Information Systems, Eighth Edition 32
Enterprise Storage Options (continued)
Figure 3.9: Storage Area Network (SAN)
3. Storage area network (SAN)
Special purpose, high speed network
Provides direct connections between data-storage devices and computer
Integrates different types of storage subsystems
Principles of Information Systems, Eighth Edition 33
Input and Output Devices: The Gateway to Computer Systems
• Through input and output devices, people provide data and instructions to the computer and receive results from it
• Selection of input and output devices depends on organizational goals and IS objectives
Principles of Information Systems, Eighth Edition 34
Characteristics and Functionality
• Nature of data- data can be human-readable or machine-readable
• Data entry: converts human-readable data into machine-readable form
• Data input: transfers machine-readable data into system
• Source data automation: capturing and editing data where the data is initially created and in a form that can be directly input to a computer
Principles of Information Systems, Eighth Edition 35
Input Devices
• Personal computer input devices– Keyboard– Mouse
• Speech-recognition technology– Input devices that recognize human speech– e.g. automate account identification process
• Digital cameras• Terminals
– Input and display devices that perform data entry and input at same time
– Office, warehouse, factory
Principles of Information Systems, Eighth Edition 36
Input Devices (continued)
• Scanning devices • Optical data readers
Special scannerOMR – standardized tests OCR – convert handwritten to typed doc into digital data
• Magnetic stripe card– Swipe card
• Point-of-sale (POS) devices– Used in retail operations to enter sales information
• Magnetic ink character recognition (MICR) devicesA system for reading banking data quicklyUse special ink readable by people and computerse.g. bank check
Principles of Information Systems, Eighth Edition 37
Principles of Information Systems, Eighth Edition 38
Input Devices (continued)
• Automated teller machine (ATM) devices• Pen input devices• Touch-sensitive screens• Bar-code scanners• Radio Frequency Identification (RFID)
Principles of Information Systems, Eighth Edition 39
Output Devices
• Display monitors
• Liquid crystal displays (LCDs)
• Organic light-emitting diodes (OLEDs)
• Printers and plotters• Digital audio player
Principles of Information Systems, Eighth Edition 40
Special-Purpose Input and Output Devices
• Computer-based navigation systems– GPSs (Global positioning system), satellite based
radio navigating system– Guide to specific destination
• Multiple function printers– Print, copy, fax,scan
• Eyebud screens– Portable media devices– Display video in front of one eye
Principles of Information Systems, Eighth Edition 41
Computer System Types, Selection, and Upgrading
Computer classification:• Special-purpose computers: used for limited
applications by military and scientific research groups
• General-purpose computers: – used for a wide variety of applications– Single user at a time, multiple concurrent users
Principles of Information Systems, Eighth Edition 42
Computer System Types
• Handheld computers – single user, small size, portable
• Portable computers – laptops, notebooks, tablet
• Thin client– Low-cost, no extra drives, limited capabilities
• Desktop computers
Principles of Information Systems, Eighth Edition 43
Computer System Types (continued)
• Workstations – more powerful than personal computer, similar size to desktop, heavy mathematical computing, CAD.
• Servers – to perform special tasks, e.g. running network or Internet application.
Computer System Types (continued)• Mainframe computers – large, powerful computer,
shared by hundreds of concurrent users, connected via terminals
• Supercomputers– most powerful computers, fastest processing speed,
highest performance.– Special purpose machines – weather forecast, military
application, simulation of golf club designs.
Principles of Information Systems, Eighth Edition 44
Principles of Information Systems, Eighth Edition 45
Selecting and Upgrading Computer Systems
• Dispose of old equipment properly• Consider factors such as speed, cost, and
performance when upgrading– Hard drive – Main memory– Printer– DVD burners
Principles of Information Systems, Eighth Edition 46
Summary
• Hardware: machinery that assists in the input, processing, storage, and output activities of an information system
• Hardware components: central processing unit (CPU), input and output devices, communications devices, primary storage devices, and secondary storage devices
• Random access memory (RAM): temporary and volatile
• ROM (read-only memory): nonvolatile
Principles of Information Systems, Eighth Edition 47
Summary (continued)• Multiprocessing: simultaneous execution of two or
more instructions at the same time• Sequential access: records must be retrieved in
order• Direct access: records can be retrieved in any order• Examples of secondary storage devices: magnetic
tapes and disks, DVDs, memory cards, etc.• Enterprise storage options: attached storage,
network-attached storage (NAS), and storage area network (SAN)
Principles of Information Systems, Eighth Edition 48
Summary (continued)
• Examples of input devices: keyboards, mice, voice-recognition devices, terminals, scanning devices, and touch-sensitive screens
• Examples of output devices: display monitors, liquid crystal displays (LCDs), printers, and plotters
• Computers can be classified as either special-purpose or general-purpose
• Computer system types: handheld computers, portable computers, desktop computers, workstations, servers, etc.