Transcript Week 2

CHAPTER 2
COMPUTER HARDWARE and
SOFTWARE
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Computer Hardware
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The physical equipment used for
input, processing, output, and
storage
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Central processing unit (CPU)
Memory (primary and secondary
storage)
Input technologies
Output technologies
Communication technologies
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Computer System Components
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Processing Characteristics
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Machine Cycle Time
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Clock Speed
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Time it takes to execute the instruction and
execution phases
Measured in Million Instruction Per Second (MIPS)
or FLoating point Operations Per Second (FLOPS)
A series of electronic pulses produced at a
predetermined rate, that affect machine cycle time
Measured in MHz or GHz (fastest desktop CPUs
today are 2.4 GHz
Both are crude measures of performance
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E.g. AMD Athlon XP 2600+ (2.1 GHz) is faster than
Intel P4 2.6 GHz
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Moore’s Law
The number of transistors in a chip will double every 18 months.
- Gordon Moore, 1965
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Moore’s Law Illustrated
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Storage Measurements
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Some devices are measured in ’metric’ bytes
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1 KB = 1000 Bytes
Gives a larger number
100 MB = 105 million Bytes
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Basic Types of Memory Chips for
Primary Storage
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Primary vs. Secondary Storage
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Primary
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Close to the CPU
Working storage
Running programs
Usually volatile
Technologies
 RAM, SDRAM,
DDR RAM
Synonyms
 Memory, main
memory
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Secondary
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large amounts of
data for extended
periods of time
typically nonvolatile
much slower than
primary storage
can be much more
cost effective than
primary storage
Technologies
 Harddisk, floppy,
CD-ROM, tape, …
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Types of Secondary Storage
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Magnetic Tapes
Magnetic Disks
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Floppy, harddisk, …
RAID
Storage area
network (SAN)
Optical Disks
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Magneto-optical
Disk
Digital Video Disk
(DVD)
Memory Cards
Expandable
Storage
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Secondary Storage Devices
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Fixed Media
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Hard disks (40-100 GB)
Redundant Array of Inexpensive
Disks (RAID)
Removable Media
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Diskette (1.44 MB)
Laser-servo diskette (120 MB)
 Combines magnetic and optical storage
Cartridge disks – e.g. Jaz (1-2 GB)
Tape (10-100 GB)
CD-ROM (640-700 MB)
 CD-R, CD-RW,
DVD-ROM (4.7GB), DVD-RAM
Flash memory (4-512 MB)
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Costs for Data Storage
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Storage Area Network (SAN)
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Storing and accessing
data is becoming
increasingly important
SAN offers
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Lots of bandwidth
Easily upgraded
Less hassle
More security
SAN is a hot topic
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Input Devices
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Keyboard and
mouse
Voice-recognition
devices
Digital Computer
Cameras
Terminals
Scanning Devices
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Point-of-Sale
(POS) Devices
Automatic Teller
Machine (ATM)
Devices
Touch Sensitive
Screens
Bar Code Scanners
Source Data Automation: Making input digitial at
the time data is created
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Hardware for Output
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Softcopy
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Video Monitors
Video Terminals
Speakers
Robotic
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Hardcopy
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Printers
Plotters
Other Hardcopy
Media
 transparencies
 microfilm
 CD-ROM
 Slides
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Computer classification
Small, slow
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Cell phone
Handheld (palm)  Note: There are also
Laptop
computers embedded
in appliances, toys,
Desktop PC
cars, etc.
Server
Workstation
Midrange (small mainframe) e.g. IBM
AS/400
Mainframe e.g. IBM S/390
Supercomputer e.g. Cray
BIG, FAST
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Computer Software
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Software History and Significance
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1950’s: Hardware was expensive. Software was less
important and less expensive.
Today: software comprises a much larger percentage
of the cost of modern computer systems
The Software Crisis: Many software projects are
delivered late, over budget with inferior quality, and
does not meet requirements/expectations
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software applications can’t keep up with rapidly
changing business conditions and rapidly evolving
technologies
new applications must be developed quickly, and
existing software must also be maintained (est. 80%
effort on maintenance)
more complexity, leads to more “bugs”
testing and “debugging” software is expensive and
takes time
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Software Model: A Layered View
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Software Classifications
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System Software
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Programs that control and support
the computer system
Supports application software by
directing the basic functions of the
computer
Facilitates programming, testing,
and debugging of computer
programs
Usually independent of any specific
type of application
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Operating Systems Functionality
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Common Hardware
Functions
User Interface
Hardware
Independence
Memory Management
File Management
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Processing Tasks
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Multitasking and
time-sharing
Networking Capability
Access to System
Resources
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Security
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Major Desktop OS
MS-DOS
Windows 3.xx
Windows 98
Windows 95
Windows NT
Windows 2000
Windows CE
IBM’s OS/2
Windows XP
Macintosh Operating System
Linux
UNIX
Java Operating System (JavaOS)
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Windows 3.11
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Windows 95
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Windows XP
Linux (KDE 3)
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Application Software
Direct a computer system to
perform specific information
processing activities and
provide functionality for users
(lets you do real work)
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Personal Application Software
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An off-the-shelf application program
not linked to any specific business
function, but instead supports
general types of processing
Data management
Spreadsheet
Desktop publishing
Graphics
Publishing
Multimedia
Speech recognition software
Word processing
Communications
GroupWare
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Software Suites
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Collections of application software
packages that integrate the functions of
the packages
Examples: Microsoft Office, Star Office,
Corel Word Perfect Office, and Lotus
SmartSuite
Generally include: spreadsheet, word
processor, database, and graphics
package
Ability to move data and diagrams among
individual application
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Enterprise Application Software
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Supply Chain Management
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Enterprise Resource Planning
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Provide real-time monitoring of business
functions
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Permits timely analysis of issues such as
quality, availability, customer satisfaction,
performance, and profitability.
A coherent system that covers all
business processes
Advantages
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Elimination of costly, inflexible legacy systems
Improvement of work processes
Increase in access to data for operational
decision making
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Upgrade of technology infrastructure
Problems with ERP
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Time and Cost
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Expensive and long implementation process
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Business issues
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Change business processes to fit system
Difficult to move to different vendor
Risks in Using One Vendor
People issues
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12-24 months
Difficulty Implementing Change
Require changes to all/most parts of the
organization
Technical problems
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Very complex systems
Difficulty Integrating with Other Systems
Systems require customization
Customization experts in short supply
Customizations may make it difficult to upgrade
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Enterprise Resource Planning
Vendors
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33% SAP
15% Oracle
8% PeopleSoft
5% JD Edwards
39% Other
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… ..
Programming Languages ……
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Different languages for different
purposes
Tradeoff between easy to program
(programmer-friendly) vs. Efficiency
in execution (computer-friendly)
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Coming up...
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Need more detail?
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Today’s presentations
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Go to www.howstuffworks.com and check out
the Computer section.
Team 1 and 2
Next week
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Lecture on Chapter 3: Databases
Presentations from Team 3, 4, and 5
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