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.