Chapter 3

Hardware and Software

Purpose

• To be an intelligent consumer of hardware products

• To ask intelligent question– What is it?– How can I use it?– Is it the best choice?

Agenda

• Computer• Hardware• Computer Data and Instruction• CPU (Central Processing Unit) and Memory• Computer Performance• Software• Computer Virus• Discussion and Case Study

Computer

• Components: hardware and software• Hardware: electronic components and

related gadgetry that input, process, output, and store data according to software

• Software: instructions encoded in computer programs

• Types: general purpose (desk top) and special purpose (cell phone)

Hardware - I• Input

– keyboard, mouse, document scanner, bar-code scanner, microphone, etc.

• Processing– Central processing unit (CPU)– CPU selects instructions, processes them, performs

arithmetic and logical comparisons, and stores results of operations in memory

– CPU is vary in speed, function, and cost– Special function cards to augment basic capabilities

(video display card)

Hardware - II

• Output– video displays, printers, audio speakers,

overhead projectors, etc.• Storage

– Save data and program– Magnetic disk, optical disk (CD, DVD),

magnetic tape• Communication

– Wire, bus, etc.

Figure 3-9 Magnetic Disk Components

Magnetic Disk

• Long-term and nonvolatile data storage• Performance depends on type and size• Recording data on magnetic disk in concentric

circles• Read/write head• Data transfer speed

– Rotational delay– Seek time– Width and speed of the channel

Optical Disk• Type

– CD (compact disk)– DVD (digital versatile disk)– The differences are their capacity and speed

• Burning a pit into the photosensitive material using a low-power laser to represent data– The presence of a pit causes light to reflect and

signifies a one– The absence of reflection signifies a zero

• Usage– Playing music and video– Nonvolatile

Video Display• Type

– CRT (cathode ray tubes)– LCD (liquid crystal display)

• Illuminating small spots on the screen called pixels to display image

• CRT monitor– The dot pitch: the distance between pixels on the screen– The smaller the dot pitch, the sharper and brighter the screen

image• LCD monitor

– The pixel pitch: the distance between pixels on the screen– The smaller the pixel pitch, the sharper and brighter the image

will be• Optimal resolution

– The size of the screen, the dot or pixel pitch, etc.

Input, Process, Output, and Storage Hardware

Computer Data and Instruction - I

• Binary digits (bits)– Zero or one– Closed or open of a switch– Orientation of a magnetic field– Light reflection of a optical media– Represent data and instruction

• Byte: 8-bit– Numbers, characters, currency amounts,

photos, recordings, or whatever

Bits Are Easy to Represent Physically

Important Storage-Capacity Terminology

Computer Data and Instruction - II

• Instruction set: a collection of instructions for directing computer process– Microsoft Windows: Intel instruction set by

Intel Corporation– Macintosh computers: PowerPC instruction

set using Powerful PC processor– Macintosh computers: either Intel or PowerPC

processor starting 2006

CPU and Memory - I

• Motherboard: a circuit board mounted and/or connected with processing components

• Main memory– RAM (random access memory)– Volatile– A set of cells holding bytes of data or instruction– Each cell has a address for identification– Speed and amount– House OS, application programs, and data

CPU and Memory - II• Cache memory

– Very fast and expensive memory to improve overall throughput of the CPU

– Stores frequently used data, intermediate results, and the most frequently used computer instructions

• CPU reads instructions and data from main memory and writes data to main memory via a data channel (bus)

• CPU speed– Cycles per second, or hertz (3.0 gigahertz or 3.0 GHz or 3 billion

cycles per second)• Data transfer speed

– The speed of main memory– The speed and width of the data bus– The wider the bus (by no. of bits), the more data transferring

Computer Performance

• Memory swapping– A request to the operating system to store

data in RAM and there is not enough free memory to store the requested data

– The operating system has to remove something to make space

– Slow down the performance• Adding more main memory to substantially

improve the computer performance

Software

• Operating system (OS)• Application software

Operating System

• Types– Windows for business users– Mac OS for arts community– Unix for scientific and engineering community– Linux developed by open-source community

for web servers• Own versus License issue

Application Software• In terms of source

– Off-the-shelf– Custom software

• in house or consultant• Difficulty and risky

• In terms of capability– Horizontal-market application software for all organization and

industry– Vertical-market application software for specific industry

• Firmware– Software installed into the device– Print server, communication devices, etc.

Computer Virus• A computer program that replicates itself, consumes the computer’s

resources, take unwanted and harmful actions• Payload: the program code causing unwanted activity• Type

– Trojan horse– Macro virus– Worm

• Prevention– Download– Email– File extension– Antivirus– OS patch

Discussion• Security (53a-b)

– How to enforce employees to follow the antivirus policy and procedure in any organization?

– State your opinions related to the statement “the viruses are developed by the antivirus software vendor.”

• Opposing forces (57a-b)– State your opinions related to the statement “the new computer

products are the conspiracy between hardware and software vendors to ripe off consumers.”

• Ethics (61a-b)– State your opinions about the major impacts in terms of social,

entertainment, government, and business operations by implementing the TCG/NGSCB (Trusted Computing Group/Next Generation Secure Computing Base)

Case Study

• Case 3-1 not 6 and 9 (69-70)• Case 3-2 only 1 and 2 (70-71)

Points to Remember

• Computer• Hardware• Computer Data and Instruction• CPU (Central Processing Unit) and Memory• Computer Performance• Software• Computer Virus• Discussion and Case Study