Transcript Takeshi Tokuyama ・ Jinhee Chun Tohoku University Graduate

情報基礎B
Lecture 3
Takeshi Tokuyama
Tohoku University Graduate School of Information Sciences
System Information Sciences
Design and Analysis of Information Systems
HISTORY AND CONCEPT OF INFORMATION
History of Computer
• Computer
– A machine that carries out arithmetic and logical
operation
– Supercomputer, mainframe, server, personal
computer, word processor, calculator and etc
Early Computers
• B. Pascal(1640?) “Pascalina”
• C. Babbage(1822) Differnce engine
• ABC (Atanasoff-Berry 1942)
– First electronic computing device
http://www.infonet.co.jp/ueyama/ip/history/eniac.html (Japanese)
Ideas by
mathematicians
• George Boole (1815-1864): Boolean Algebra
• Alan Turing(1912-1954): Turing machine:
Basic idea of logical process by a computer
– Charch-Turing thesis: Computable functions
• Turing decoded the famous Enigma crypto of Nazis
• John Von Neumann (1903-1957)
– Idea of “computer program” (stored program)
• Claude Shannon(1916-2001)
– Information theory and switching circuit
Boolean algebra and computing
• Boolean algebra: Algebra on 0 and 1
– 0⊕0 = 0, 0⊕1=1⊕0=1, 1⊕1= 1 (AND operation)
– 0⊗0=0, 0⊗1=1⊗0=0, 1⊗1= 1 (OR operation)
– NOT(0) = 1, NOT(1)=0 (NOT operation)
• Every computation can be represented
• AND, OR, NOT can be realized electronically
– Relay, transistor, etc
• Information coding (Shannon) : Transform every
information by sequences of 0 and 1 (bit
sequences)
The first computer in use
• ENIAC (Electronic Numerical Integrator and Computer)
– First general purpose electronic computer
– Invented by John William Mauchly and John
Presper Eckert in 1942
http://www.infonet.co.jp/ueyama/ip/history/eniac.html (Japanese)
• ENIAC (Electronic Numerical Integrator and Computer)
– Floor area: 100㎡, Length: 30m, Weight: 30t,
Power Consumption 150kW
– Developed secretly on military purpose such as
trajectory calculation and Cryptanalysis
http://www.infonet.co.jp/ueyama/ip/history/eniac.html (Japanese)
Hardware Architecture
Control Unit
Instruction
Load
Processing
Instruction
Processing
Unit
Data
Read & Write
Program
Container
I/O Controller
Main Memory
I/O Device
– Control Architecture operates those transaction
– Operating System shares those devices
File and Folder
• File
– A block of information
•
•
•
•
Document file
Program file
Image file (a picture from a digital camera)
Audio file (ex: a song in CD)
– File Size
• KB: KiloByte
• MB: MegaByte …etc
File and Folder
• Folder (“Directory” in Linux)
– A virtual container which groups files and other
folders
– ex)
• Music folder which contains audio files
• “My Document” or “Home Directory” in your account
at Tohoku University
– Common file system in almost all operating
systems
OS
• Operating System
– Multi Task
• Internet browser, music player, text editor and mailer
are available at the same time
– Share storages for various purpose
– Required to use storage efficiently and keep in
order
OS
• History of OS
– MVS/CMS: OS for IBM Mainframe
• Multiple Virtual Storage
• Conversational Monitor System
• System/360(1964) has established Mainframe features
–
–
–
–
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–
UNIX: Typical workstation OS
MS-DOS: De facto standard of OS on early PC
Windows, MacOS: Main OSs on current PC
TRON: Japanese OS used inn cellphone
LINUX: UNIX for PC
Android
UNIX System
•
•
•
•
MULTICS -> UNIX
1983 Published by AT&T Bell Labs
1985 UC Berkley distributed lite edition
Features
– Tree structure file system
• Epoc making idea
• Adopted in Windows, MacOS and etc
– Open source
– Various tools and free software
– Many excellent algorithms
• Data search, data checking, etc
• Linux for PC
– Developed by Linux Torvalds
File Structure
/
usr
www
home
b1v
system
local
b1c
b1cb123?
bin
b0
/usr/home/b1c/b1cb123?
Home directory for a student
Why tree structures?
• Tree structure is magic to handle large data
– I have more than 1000,000 files in my own PC
– We have more than 1000,000,000 web pages in the
world
– How to organize them?? Tree is the solution.
• www.dais.is.tohoku.ac.jp/~tokuyama/profile.htm
– By using a tree with 6 layers with 20 branches at each
node, how many information can be represented?
Windows
• The name comes from “WindowSystem”
• Bill Gates: DOS and Windows, a software business magnate
• Mouse click and icons
– So as MacOS
• Easy operation targeting personal users
– Simple installation
– Highly functional software(ex.Microsoft Office)
• Maintenance and version up by Microsoft
– Win 95 -> 98 -> … -> XP -> Vista -> 7 (not free)
What is file name?
• File name consists of name and extension
– Doc1.txt
• Extension is a type of file
• Some applications use their own extensions
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–
–
–
–
mytext.txt (text file)
mydocument.doc (MS Word 97-2003 document file)
mydocument.docx (MS Word 2007- document file)
myweb.html (html file: for web design)
mypicture.jpg (picture file)
File Operation
• Open “MyDocument” from icon
• Create folders below
– practice
– assignment
– handout
• Move files from folder to another folder
• Create file and copy them
COMPUTER BASICS II
INTERNET
Internet
• History of the Internet
– 1970s: Development on packet communication and
TCP/IP(Transmission Control Protocol / Internet Protocol)
– 1980s: ARPANET(Pentagon and UC Berkley)
• Academic, Military, Aviation, Space Development
• IBM VNET: Corporate network
– 1990s: Practical Internet based on e-mail
• Alternative communication method to mail and phone
• For hearing-impaired person (MCI VIntonCerf)
– 1990s latter half: www(world wide web)
• one-to-many multimedia information service on web page
• Development exceeding TV
– 2000s: mobilization(cellphone)
Internet
• WWW(World Wide Web)
– Multicasting information service
• Open to everybody: one-to-many
• User select information he/she need
– Search Engine
• i.e. google
– Links between texts with Hypertext
– Visualization on Internet Browser
Internet
• The result of interconnecting computer
networks
• Networks in home, office and School are
connected to the internet via internet provider.
Internet
Internet Provider
LAN: Office, University
Internet
• Server
– Provides services across network
– Each server provides essential service on demand
• Mail Server
• Web Server…etc
– Those server enables
• E-mail
• Web browsing
• File transferring…etc
Internet
• IP address(Internet Protocol Address)
– Number to identify a machine on network
– Each computer has different ones
– Numbers and dots
• Ex) 192.168.0.1
– Provided by agency in each country
• JPNIC(Japan Network Information Center)
Internet
• Domain name
– cs.he.tohoku.ac.jp
– http://www.ise.he.tohoku.ac.jp
• Domain name is converted to IP address in
DNS server so that to send information to
receiver
website
• Collection of related web pages on the
internet
• Internet Browser is used to visit website
– URL(Uniform Resource Locator)
• A sort of address, indicates a place of information
Website
http://www.google.co.jp/
Enter URL
Send Web page
Web Server
Web Browser look for the web server
on the internet and display web site
Website
• HTTP
– HyperText Transfer Protocol
– Protocol between web browser and web server to
send and receive contents
• HTML
– HyperText Markup Language
– Language for website
– Links between web pages, photos, movies
E-mail
SMTP
Internet
MTA
SMTP
MTA
MUA
MUA
– MUA(Mail User Agent)
• Mailer
– MTA(Mail Transport Agent)
• Program on mail server
– SMTP(Simple Mail Transport Protocol)
E-mail
• Mail Address
– Consists of user name and domain name
[email protected]
– Domain
• Indicates address of mail server
• Usually, name of university or company in which user
belongs
E-mail
[email protected]
Computer System for
Education of Infomatics
Fifth Level Domain
Center for the Advancement of
Higher Education
Fourth Level Domain
University domain name
Third Level Domain
Academic
Second Level Domain
Japan
Top Level Domain
E-mail
• Mail Address and IP Address
[email protected]
– Mailer sends message to IP address converted
from mail address
130.34.129.xxx
– POP server(works as post office) receives e-mail
E-mail
• Example of mail transport
– Prof. Aronov(NYIT) to Tokuyama
US Academic
Network
edu
poly.edu
NY Institute of
Technology
ac.jp
JP Academic
Network
tohoku.ac.jp
Tohoku University
is.tohoku.ac.jp
Mail Server: ziggy
128.238.32.77
[email protected]
dais.is.tohoku.ac.jp
Graduate school of
Information Sciences
Tokuyama Lab
Mail Server: masamune
130.34.233.xx
[email protected]
E-mail
• Writing e-mail
– Write in an appropriate format
•
•
•
•
Sender and Title should be clear
Not a chat
There is log
Never tell a bad thing
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Google
• Search Engine on the internet
• Founder
– Sergey Brin, Larry Page
http://www.google.co.jp/intl/ja/about/corporate/company/execs.html