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