Transcript Chapter 3

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