Intelligent Information Systems
1. Internet History
Gio Wiederhold
EPFL,
April-June 2000, at 14:15 - 15:15, room INJ 211
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Schedule for Seminar Course on
Presentations in English -- but I'll try to manage discussions in French and/or German.
• I plan to cover the material in an integrating fashion, drawing from concepts in
databases, artificial intelligence, software engineering, and business principles.
1. 13/4 Historical background, enabling technology:ARPA, Internet, DB, OO, AI., IR, XML.
2. 27/4 Search engines and methods (recall, precision, overload, semantic problems).
3. 4/5 Digital libraries, information resources. Value of services, copyright.
4. 11/5 E-commerce. Client-servers. Portals. Payment mechanisms, dynamic pricing.
5. 19/5 Mediated systems. Functions, interfaces, and standards. Intelligence in
processing. Role of humans and automation, maintenance.
6. 26/5 Software composition. Distribution of functions. Parallelism. [ww D.Beringer]
7. 31/5 Application to Bioinformatics.
8. 15/6 Educational challenges. Expected changes in teaching and learning.
9. 22/6 Privacy protection and security. Security mediation.
10.29/6 Summary and projection for the future.
• Feedback and comments are appreciated.
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The origin: ARPAnet
• Motivation
– Share expensive computing resources funded at
5 principal research sites by ARPA
– services needed
• TELNET -- remote execution control
• FTP -- file transfer needed for TELNET
• messaging for synchronization -- email - SMTP
– requirements
• handle heterogeneity
• survivability
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(D)ARPA
• (Defense)
– internal motivation, >, < f(political climate)
• Advanced Research
– not undertaken by industry (by need)
• Projects
– limited time, intense support
• Agency
– started 1958 - post sputnik - rocket science
– Information science started ~1967 IPTO
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Technologies
• Platform, representation independence
– ascii(7), bcd (6), ebcdic (8), binary (any size)
• Packeting
– limits buffer lengths, allows rerouting
• Dynamic path determination
– nodes decide next best node -- now by DNServers
– (versus other systems -- initially
• Uunet required specifying all nodes
• NASA network had direct connections
• VMnet central directory
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Growth - exponential
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1969 - 5 nodes, 4 computing sites
1972 - ~ 12 nodes, 37 sites
~1976 - ad hoc gateways to other nets for email
1979 - many computer scientists have/need access
1981 - Stanford & Xerox router / gateway protocols
1985 domain naming x.y.typ / Internet Protocol (4 segment) addresses
1991 - base for NREN, NSF backbone; except for x.y.mil
1992 - commercial domains permitted - ICANN established
1993 - 15M users, 3M paying
1994 - Digital Library initiative
1995 - fully commercial operation, research use by grants
1996 - NSF research initiative New Generation Internet
1999 - 2.2M sites on Internet, 288M public pages
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Initial configuration
• BBN - development node - IMP [Bob Kahn]
– Lockheed mini-computer
• SRI - documentation node - RFCs [John Postel
– DEC PDP-10
• UCLA - network science node [Leonard Kleinrock]
– IBM 360
BBN
SRI
• UCSB - software node [Feldman, … ]
– SDS Sigma 7 (~ 360 architecture)
UT
SB
LA
• Utah - graphics hardware node [Ivan Sutherland, Evans, ]
– SDS 940
Each node has multiple connections to other nodes
Nodes can serve more than one computing site
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Packeting and IMPs
IMP (interface message processor)
must deal with
A
• Limited memory
M
• Unreliable communications
• Long sessions & big files
b c
TCP Transmission Control Protocol:
Packeting and Packet Switching A,G, 2, 202, mno
(used in AlohaNet, 1962 [Abramson] )
• splits up messages, files into
independently portable units: packets
{ from, to, number, size, data }
EPFL - Gio spring 2000
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C
A,G, 1, 256, i jk l
Each node reads header, makes
forwarding decisions based on a table
(can change dynamically)
B
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A here
B use b
C use c
D use b
E use c
F use c
G use b
g
A use b
B here
C use b
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Development
Informal, distributed over the user community
• Request For Comment RFCs
collected at SRI, adopted when they made sense to enough
participants, as demonstrated by prototypes, can become standards
• RFCs available now at Network Solutions Inc
• allowed growth without a central authority
 Is that a generalizable principle ?
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More early participants
•
IMPs could handle 4?? computer sites
– (I.e., at SRI: SRI PDP-10, Stanford SAIL PDP-6, SUMEX)
•
added Terminal Interface Processors (TIPs)
– for terminals (AT&T TTY, DEC VT100, …) only
• More IMPs, TIPs, but restricted to ARPA contractors
Other networks, other technologies
• IBM VMnet internal, then external IBM customers
– central naming authority
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NASA for sharing its satellite data processing
– high bandwidth, mainly Telnetting
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UUnet for Unix users and ARPAnet sites
– periodic forwarding, name in message all intermediate nodes
– access to Europe (fast via SEISMO in Norway)
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Email ? !
• Initially - at Telnet login show system status – local time, up/busy/down, special situations
• Add arbitrary messages
• As need for remote computing diminished use of E-mail increased - new communication medium
Formalized 1982 by RFC 821 Simple Mail Transmission Protocol
 Serendipitous major social / research benefit
• Many Related Functions
– bulletin boards ...
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ETHERNET
Novel protocol for broadcast medium [Metcalfe, Bogg, Shoch]
• Also developed in Aloha net (Hawaiian islands)
• collision detection (CD) protocol
– no synchronization, fully distributed
– relatively long latency in space and on wire -causes collisions -- crossed, mixed signals
– listen while sending, when coll. detected stop both!
– resend with exponential backoff (wish humans would do that)
– simple and stable to fairly high utilization
• outperformed at high rate theoretically only
Used for local networks, with gateways to Internet
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INTERNET
Backbone providers
– UUNet (1993), SPRINT, AT&T, MCI, GT&E, Worldcom +European PT&Ts
serve regional networks, large users (CNN, …)
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• share resources by free peering at gateway nodes
Regional subnets and ISPs distribute bandwidth to
1. Consumers (#=n) may pay / are seen as having value
 Metcalf’s law: the value of a net is ~ n 2
2. Smaller ISPs
All dealers oversubscribe: Sell more bandwidth than they buy
– count on fractional use
– don’t need to buy for intra-region / intra-ISP traffic
• Peripheral buffering services can reduce traffic further (MIT AKEMI)
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HTML
• Hierarchical Text Markup Language
– sharing of physics preprints [Tim Berners-Lee @CERN]
– markup = embedded format commands for layout
• Multi-part, multi-representation (text, figs) documents
• Markups per SGML + (hyper = external) links
– SGML = IBM initiated standard graphic document markup
– basic commands are size, font, color independent,
to be interpreted by the publisher for report, book, manual, ...
Alternative to (a.o.) (also UNIX runoff, … )
• XEROX initiated Postscript (PS), Adobe PDF
– exact bit-wise layout via executable script
• TEX markup Detail (pretty math) [Knuth], LATEX macros [Lamport]
– generates device independent format (DVI), then PS
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Web
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Browsers for HTML
Mosaic [Andressen, Bina at UIUC]
Netscape …
Search engines (Topic 2)
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XML
Machine Processable !
• return to origin?
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ARPAnet -- share heterogeneous machines
Email -- people-to-people
Digital Library -- people-to-machines
E-commerce (E2B)-- people-to-machines
• client-server
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Mediated -- people-to-services-to-machines
Business (B2B)-- machine-to-machine(s)
Business services -- machine-to-services-to-machines
Ubiquitous -- gadget-to-gadget
Future
• (embedded)
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Fin
Comments?
• what was new / what was old or boring?
• future emphasis
– more technological detail?
– more situational detail?
– more extrapolation to the future
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