UMBS Reunion 2001 Current issues in Internet technology Scott A. Moore Associate Professor, Computer...
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UMBS Reunion 2001 Current issues in Internet technology Scott A. Moore Associate Professor, Computer & Information Systems Personal home page: http://www.samoore.com/ These slides: http://www.samoore.com/teach/reunion/2001/
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Transcript of UMBS Reunion 2001 Current issues in Internet technology Scott A. Moore Associate Professor, Computer...
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Current issues in Internet technologyScott A. Moore
Associate Professor, Computer & Information SystemsPersonal home page: http://www.samoore.com/These slides: http://www.samoore.com/teach/reunion/2001/ e-Lab home page: http://elab.bus.umich.edu/ Email: [email protected]
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What I have planned
• Basic Internet-related terms• Open source software• XML• Web services• Wireless & mobile computing• Home computing• Microsoft
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Basic Internet-related terms and concepts
• The next few slides– How the Internet
works– What are cookies– Peer-to-peer file
sharing (e.g., Napster)
– Encryption– N-tier applications
• What we’re going to touch on– Switches, hubs, &
routers– DNS– Servers– Cookies– Clients– N-tier– Peer to peer– Encryption
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DNS
Comp
Comp
CompWeb browser
Switch
Web server
Router
RouterSwitch
Now the request is for file index.php on 141.211.239.168 using the http
protocolWhere the heck is www.samoore.com?
http://www.samoore.com/index.php
And here we have the machine
141.211.239.168
It retrieves the file called index.php. This might look something like“<html><head><title>Hello</title></head><body><p>What’s up?</p></body></html>”.
Each of these connections might be hundreds of yards or hundreds of
milesHolds a list that tells relationship between domain names and IP
addresses: e.g., www.samoore.com ->
141.211.239.168
And now the Web browser figures out how to display this HTML file in a window.
How the Internet works
Or it might be a “hub”
LAN
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What are cookies?
DNS
Comp
Comp
CompWeb browser
Switch
Web server
Router
RouterSwitch
Give me that file!Okay, here’s that file, and by the
way, idNumber=15.
Cookies.txt:idNumber=15
Give me another file, and by the
way, idNumber=15.
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Peer-to-peer file sharing (e.g., Napster, Gnutella, Morpheus)
Comp
DNS
Comp
Comp
CompWeb browser
Switch
Web server
Router
RouterSwitch
These are real hard and quite expensive to set up for large scale operations.
Free, easy to use software for sharing
files. Unknown administrator.
napster
napsternapster
napster
file
file
I see all these peer-to-peer music-sharing applications fading to
irrelevance once the music industry gets its act together concerning on-
line music distribution.
Suppose you’re sitting at this computer and you’re looking for a specific file.
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Encryption
Comp
DNS
Comp
Comp
CompWeb browser
Switch
Web server
Router
RouterSwitch
I wanna buy something! Here’s my credit card
number: 23133.
This is not good since there might be bad guys here.Encrypted
message: 3ls9df[m42l;9asd09=8fgPoka0sdkf09
=as
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Open source
• A new way to develop and distribute software
• Related to concept of “free”• Basic meaning:
– Make source code of program available to anyone and everyone
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Meaning & use of “source”
Programmer
writes
Sourcecode
In some language (C++, Java, etc.), dozens, hundreds, or thousands of lines of code
…Echo “Hello Alumni!”;…
compile
ExecutableProgram
(e.g., msword.exe)
This is what’s sold
This is usuallyFiercely guarded
…0110 1001 11001101 1100 0011…
A specialized program that converts from source to executable for a certain operating system.
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Concept of “free”
• In English, two differing, easy-to-confuse interpretations
Free beer Free speech
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Free download
Types of software“Open source”
Free
Closed
Shareware
ProprietaryPublic domain
XFree86 Style
Copyleft
GPLed
JavaWord
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Why go the open software route
• Reliability• Development speed• Lower overhead• Learn more about the customer• Distribution to a wider number of
platforms
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How to make money in open source software
• Sell support & related services• Sell accessories• Widget frosting• Loss leader
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Keep up withpace of change
One company’s reasoning
Open source
Moreusers
Bettercode More
platforms
More & betterword of mouth
“Safer”choice
Software
Moreconsulting
$
More straight-forward storyCheaper & easier to grow from zero
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XML
• Uses & magical curative powers• Compare with HTML
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XML versus HTML
HTML
XML
describes Web pages
describes anything I wantit to describe
ScottML
A specific language
Can be used to define this new
language
Again, this is a specific language
So: XML is a language that is used to define other languages
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XML
• Focus– Describes content, not display– Allows automatic checking of document
format– With little effort, can be used to display
document as well– Computing platform neutral representation
• A huge industry unto itself• If your company is not involved in XML
standards-setting activities, it’s a mistake
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Web services: Basic concept
• Integrating applications over the Internet
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A monolithic application
Application
Computer
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Client/server computing
ClientApplication
ServerApplication
Specially-crafted software
connection
Specially-chosen set of clients for a particular server
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WebService A
WebService B
WebService C
Web services-based
Applicationserver
Webbrowser
Webserver
Internet based,XML-based
data-sharing
Directory WS A WS B WS C
Possibly a supply chain management
application
Plug & Play kind of tools
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Web services: Examples
• Credit card validation• Stock quotes• Supply chain interactions
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• Small storage systems– 1GB disks the size of a quarter is no big
deal– Flash memory is low-power alternative
• Wireless communication– Bluetooth– WAP– Current cellular– 2.5G cellular
Wireless & mobile computing
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Wireless communication among nearby devices
• Standard put forth by the Bluetooth consortium
• Devices within 10 yards
• No need for line-of-sight
• Examples– Headphones to CD
player or cell phone
– Computer to cell phone
– Keyboard or mouse to computer
– Palm to computer or cell phone
– Grocery shelf to shopping cart
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Ericsson EPOC phone
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GPS device attached to Palm
Samsung just announced a cell phone with integrated GPS
capabilities
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Home computing
• Wireless LANs– 802.11b: 11Mbps– 802.11a: 54Mbps
• Broadband access– DSL– Cable– Satellite
• Don’t forget about security– Firewalls
I’ve installed this at home and it was real easy to do.
Can work with PC, Mac, Linux.
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Microsoft
• Courts– Final finding of fact is that it is a
monopolistic competitor– Going to have to play nicer
• 9/11 & Code Red– Going to have to be more security
conscious– IIS & Outlook are particularly worrisome
• XP– No big deal
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Lots going on related to computing
• Wireless & mobile• Distributed applications• Security is becoming a bigger factor• Free programs and tools
