Hardware & softwares

Fundamentals of Information Systems, Second Edition

1

Hardware and Software

Chapter 2


2

Learning Objectives

– Identify and discuss the role of the essential hardware components of a computer system.

– List and describe popular classes of computer systems and discuss the role of each.

– Outline the role of the operating system and discuss how operating systems have evolved over time.

– Identify and briefly describe the functions of the two basic kinds of software.


3

Computer System Components

Math calculations

Access, decode, coordinate instructions

Hold program instructions and data


4

Hardware Components in Action

• Instruction phase– Step 1: Fetch instruction– Step 2: Decode instruction

• Execution phase– Step 3: Execute the instruction– Step 4: Store the results


5

Execution of an Instruction


6

Processing and Memory Devices


7

Processing Characteristics and Functions

• Machine cycle time: Time to execute the instruction phase

• Clock speed: – Rate at which electronic pulses are produces.– Measured in MHz

• Wordlength– Bit (Binary digiT): 0 or 1– Unit for moving data– Wordlength: The number of bits a CPU can process in

a unit time– 32-64 bit processors


8

Moore’s Law

• Number of transistors doubles every 18 months


9

Number of Bytes


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Types of Memory (1)

• Random access memory (RAM)– Volatile– Extended Data Out (EDO) RAM– Dynamic Ram (DRAM)– Synchronous DRAM:

• Faster transfer speed between memory and processor


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Types of Memory (2)

Read-only memory (ROM)– Non-volatile– Permanent data and instructions from

manufacturer– Types

• PROM: Programmable• EPROM: Erasable programmable


12

Basic Types of Memory Chips


13

Secondary Storage and Output Devices


14

Cost Comparisons for Various Forms of Data Storage


15

Secondary Storage Access Methods

• Sequential access– Access in the same order it was written– Ex: Need to access memory location 5. Then, you

need to go through 1, 2, 3, and 4 first.

• Direct access– Directly access the location– Faster than sequential access

• Sequential access storage devices (SASD)• Direct access storage devices (DASD)


16

Secondary Storage Devices (1)

• Magnetic tapes: Similar to audio tapes, SASD• Magnetic discs: Hard disk, DASD• RAID: Redundant array of independent

inexpensive disks– Data stored more than once in one of the disks– Even if one disk fails, data can still be retrieved

• SAN: Storage area network– Consist of many storage devices

• Optical discs, DASD– CD-ROM


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Secondary Storage Devices (2)

• Magneto-optical discs• Digital versatile discs (DVD): Up to 17 GB

storage• Memory cards

– Installed in a slot– Portable

• Expandable storage: Removable disk cartridges– Portable– Zip drives


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Types of Secondary Storage


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Hard Disc


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Storage Area Network


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Digital Versatile Disc Player


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Expandable Storage


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Comparison of Secondary Storage Devices


24

Input Devices

• Personal computer input devices– Keyboard– Mouse

• Voice-recognition devices– Microphone– Software to convert voice into bits

• Digital computer cameras– Record images and video

• Terminals– Connects to a powerful server for computations

• Scanning devices– Page– Handheld

• Touch-sensitive Screens


25

A PC Equipped with a Computer Camera


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Output Devices

• Display Monitors– Cathode Ray Tube (CRT)– Wide– Lights up pixels

• Liquid Crystal Displays (LCDs)– Flat panel

• Printers and Plotters– Speed measured in pages (page printed per minute)

• Music Devices– MP3 Players


27

Laser Printer


28

Types of Computer Systems


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Overview of Software


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Overview of Software

• Computer programs: Sequences of instructions• Documentation: Describe program functions• Systems software: Coordinate the activities of

the hardware• Computer system platform:

– Hardware configuration + systems software

• Application software: Programs that help users with certain tasks


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Classifying Software by Type and Sphere of Influence


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Systems Software


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Operating Systems

• Perform common computer hardware functions– Ex: Get input from keyboard

• Provide a user interface– Command-based user interface (ms-dos)– Graphical-user interface (windows)

• Provide a degree of hardware independence– Application program interface

• Manage system memory– Convert logical view to physical view


34

Operating Systems

• Manage processing tasks– Allocate computer resources– Multitasking (run more than once application at a

time)– Time-sharing (allow multiple access to a system)

• Provide networking capability– Enable connection to the Internet

• Control access to system resources– Authentication

• Manage files– Access to files


35

Role of the Operating System


36

Application Program Interface


37

An Example of the Operating System Controlling Physical Access to Data


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Popular Operating Systems


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Workgroup Operating Systems

• Windows 2000 Server• Unix• Netware• Red Hat Linux• Mac OS X Server


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Consumer Appliance Operating Systems

• Windows CE .NET• Windows XP Embedded• Handheld PC• Pocket PC• Palm OS


41

Application Software


42

Sources of Software


43

Proprietary and Off-the-Shelf Software


44

Examples of Personal Productivity Software


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TurboTax


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Quicken


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Word Processing Program


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Spreadsheet Program


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Database Program


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Graphics Program


51

Software Suites


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Enterprise Application Software


53

Use of Integrated Supply Chain Management Software


54

Selected Enterprise Resource Planning Vendors


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Summary of Programming Languages

• First: Computer interactions written in machine code– Machine language

• Second:– Abbreviations for common operations– Assembler converts code to machine language– Assembly language

• Third– Instructions are English-like– Compliers convert code to machine language– Fortran: Good for scientific computing– Cobol: Good file handling– Java: Good for Web applications


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Summary of Programming Languages

• Fourth– Even easy for non-programmers– Tell what to do, not how to do it– Focus, Powerhouse

• Visual Programming Languages– Point-and-click– Drag-and-drop – Useful for user interfaces– Visual Basic, Visual C++

• Object-oriented Languages– Objects contain data, methods to operate data– C++, Java


57

Summary

• Hardware devices work together to perform input, processing, data storage, and output.

• There are two main categories of software: systems software and application software.

• An operating system (OS) is a set of computer programs that controls the computer hardware to support users’ computing needs.

• Application software may be proprietary or off-the-shelf.

• There are five generations of programming languages, plus object-oriented programming languages.

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