chapter 2 – part 1 hardware and software. why learn about hardware and software? fundamentals of...

Chapter 2 – Part 1

Hardware and Software

Why Learn About Hardware and Software?

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Organizations invest in computer hardware to: Improve worker productivity Increase revenue, reduce costs Provide better customer service

What is Hardware ?

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Hardware refers to the physical components of a computer that perform the input, processing, storage, and output activities of the computer.

Hardware Components (continued)

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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

Hardware Components (continued)

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System unit

System Unit Components6

Central Processing Unit (CPU): The part of the computer that consists of three associated elements: Arithmetic/logic unit the control unit the register areas

CPU Components

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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.

the register areas A special, high-speed storage area. All data must be

represented in a register before it can be processed.

Processing and Memory Devices: Power, Speed, and Capacity

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Primary memoryholds program instructions and data, is closely associated with the CPU.

Processing Characteristics and Functions

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- organizations use a variety of measures to measure processing speed. 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. Electrical current must flow through a medium from point A to

point B. The speed at which it travels between points can be increased by

either reducing the distance between the points or reducing the resistance of the medium to the electrical current.

Memory Characteristics and Functions

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Memory: Located physically close to the CPU to decrease

access time Provides the CPU with a working storage area for

programs and data Rapidly provides data and instructions to the

CPU

Storage capacity: Data is stored in memory as a combination of on

or off circuit states. byte (B): Eight bits that together represent a

single character of data.

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Memory Characteristics and Functions (continued)

Types of Memory

Random Access Memory (RAM)

Read-Only Memory (ROM)

1. Volatile memory

2. RAM chips consist of millions of switches that are sensitive to changes in electric current.

3. Read/write memory

1. Permanent storage

2. NonVolatile

3. programs and data from the computer manufacturer

4. Can be read, but not overwritten

Multiprocessing

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Multiprocessing: Simultaneous execution of two or more

instructions at the same time. There are a number of forms of

multiprocessing:

1. Multicore microprocessor: Combines two or more independent

processors into a single computer to share the workload and boost processing capacity.

Multiprocessing (continued)

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2. Parallel computing: Simultaneous execution of the same task

on multiple processors to obtain results faster

The most frequent uses for parallel computing include modeling, simulation, and analyzing large amounts of data.

Secondary Storage

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Secondary Storage

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Secondary storage: Compared with memory,

offers the advantages of: Nonvolatility greater capacity greater economy.

Considerably slower than memory.

Secondary Storage

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The selection of secondary storage media and devices requires understanding their primary characteristics: Access method Capacity Portability.

Access Methods18

Data and information access can be either sequential or direct. Sequential access:

Data is stored and retrieved in a sequential process. Must be accessed in sequence by searching through prior

data. Devices used called sequential access storage devices

(SASDs) such as : Magnetic tape.

Direct access: Records can be retrieved in any order Devices used are called direct access storage devices

(DASDs) such as magnetic disks.

Secondary Storage Devices19

Magnetic tapes: Primarily for storing backups of critical organizational data magnetized to represent bits sequential access storage medium access is slower, and usually less expensive than disk

storage.

Magnetic disks: Direct-access storage device. fast data retrieval high capacity Reasonable cost Hard Disk Drives & Floppy Disks (diskettes)

Secondary Storage Devices (continued)20

Optical discs: Common form of optical disc on which data cannot be modified once

it has been recorded: compact disc read-only memory (CD-ROM) CD-recordable (CD-R) CD-rewritable (CD-RW)

Digital video disc (DVD): Storage medium used to store software, video games, and movies

A Universal Serial Bus (USB) USB flash drives are external to the computer and are

removable and rewritable.

Input Devices

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Input Devices22

Devices used to input general types of data:1. Personal computer input devices

A keyboard and a computer mouse are the mostcommon devices used for entry of data

2. Speech recognition technology Enables a computer equipped with a source of speech

input such as a microphone to interpret human speech as an alternative means of providing data or instructions to the computer.

Speech recognition SW requires voice recognition training.

Discrete speech recognition: requires pauses between each word.

Continuous speech recognition (CSR) recognizes continuous speech.

Input Devices23

3. Digital cameras record and store images or video in digital form

4. Touch-sensitive screens Display screens which function as input as well as output

devices. By touching certain parts of a sensitive screen, you can

execute a program or cause the computer to take an action

5. Optical data readers Special scanning device to scan documents.

Optical mark recognition (OMR) readers for test scoring. Optical Character recognition (OCR) readers use reflected

light to recognize and scan various characters. Can convert handwritten or typed documents into digital data

Input Devices (continued)

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Radio Frequency Identification (RFID)

A technology that employs a microchip with an antenna to broadcast its unique identifier and location to receivers.

Output Devices

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Output Devices

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1- Display monitorsUsed to display the output from the computer Types:

Cathode-Ray Tube (CRTs):

Used to display images ,it generate one or more electron beams. A dot on the screen called a pixel lights up. 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

Cathode-Ray Tube (CRTs)

Output Devices (continued)

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2- 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

Output Devices (continued)

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3- Digital audio player Can store, organize, and play

digital music files

4- E-books: Digital media equivalent of a

conventional printed book

Computer System Types29

Fundamentals of Information Systems, Sixth Edition

Computer System Types

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Computer systems: Can range from desktop (or smaller)

portable computers to massive supercomputers that require housing in large rooms

Computer System Types31

Computer System Types

Portable Computers

Nonportable

Computers

Nonportable Single-

User Computers

Multiple-User

Computer Systems

1- Portable Computers

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They are small enough to carry easily. Portable computers include : handheld computers laptop computers notebook computers netbook computers tablet computers.

Portable Computers (continued)

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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)

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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

2- Nonportable Single-User Computers35

Thin client: Low-cost, centrally managed computer with

no extra drives (such as CD or DVD drives). Desktop computers:

A relatively small, inexpensive, single-user computer that is highly versatile.

Thin client computerDesktop computer

Nonportable Single-User Computers (continued)

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Workstations: More powerful than personal computers but

still small enough to fit on a desktop. used for mathematical computing,

computer-aided design, and other high-end processing.

2- Multiple-User Computer Systems

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Server: More powerful than workstations. Used by many users to perform a specific

task, such as running network or Internet applications

Multiple-User Computer Systems (continued)

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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

Mainframe computer Supercomputers

Computer System Types (continued)

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Computer System Types (continued)

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