Online flirtation
(not among the public,
but between remotely-separated
male and female telegraph operators during idle downtimes)
existed from the start,
and often led to real world encounters.
The telephone system:
When the telephone system started in 1876,
it was like (a). Each phone needs link to each other.
Soon replaced by (b). Switching office sets up
temporary circuit between
caller and callee for a call.
Switching office can only cover limited number of local phones.
To make long-distance calls (between phones served by different switching offices),
model in (c). 2nd level switching office.
Eventually 5 levels.
Irish business letterhead from 1898,
showing both telegraph and telephone contacts.
"Internet no.3" - The Internet, 1969 onwards
The Internet has been running since 1969
(Arpanet).
(a) Phone network.
Failure (or destruction) of a few key nodes can fragment network into a number of
isolated islands.
(b) Proposed distributed network,
Paul Baran,
1960.
Each node also acts as a router.
Myth: The Internet grew
out of the military's
nuclear war communications network.
Truth:
What happened was there were military-inspired studies
in the early 1960s
of how to built a robust network that could survive attack
- notably first-strike nuclear attack.
The answer is to decentralise everything,
including addressing and routing, to have no essential HQ,
and also to have
redundant paths.
Major US academic research centres (including military research bases
with links to academia)
took this idea in the late 1960s
and built the Arpanet network that eventually evolved
into the Internet. It was full of scientists and
university academics
from the start.
Growth of Arpanet from (a) 1969
to (e) 1972.
The modern US military/intelligence/diplomatic branches
have a number of
private global networks, including:
The Internet was originally set up not for email,
not for sharing papers, documents or programs,
not really for user communication at all in fact,
but rather to allow sharing of expensive
hardware (run programs remotely on someone else's
expensive federally-funded computer).
Email
was a surprise when it took off on Arpanet
in the early 1970s.
Later, email discussion lists started, and the
usenet
decentralised discussion-group system,
1979.
File sharing would be done between sites when they worked together
on a project.
Later came the concept of a permanent
archive of files
that anyone on the network could access at any time.
Archives of programs were set up, and later archives of
documents of all sorts.
It was not until the mid-1980s that it became clear
that an embryonic electronic "library" of documents was starting to be
built up online.
Now, of course, the library has billions of documents.
Internet had steady growth and usefulness through 1970s, 1980s,
and early 1990s,
but did not really take off until Web
idea invented.
As late as 1993, there was (almost) no business
and (almost) no home civilian users on the Internet.
It was still dominated by the academic, scientific, non-commercial users
that had always dominated it.
But the infrastructure was in place for an explosion in both business and civilian use.
The Internet is older than that
- but used a different addressing scheme before 1985.
whois nordu.net
shows creation on 1 Jan 1985.
This is
NORDUnet,
the research and education network of the Nordic countries. nordu.net
still exists.
whois symbolics.com
shows creation on 15 Mar 1985.
This was a company called
Symbolics
which is now defunct.
symbolics.com
has been sold, and survives now as a novelty -
the oldest .com in the world.
The killer app - Mosaic web browser, 1993
Web invented as a system running on the Internet 1989
(Tim Berners-Lee, CERN),
but did not take off until had a mouse-driven interface
- Mosaic, 1993
(Marc Andreessen, NCSA).
Web explodes. Internet explodes.
A "web server" originally meant a single physical server.
It still does, for some sites.
We can have these situations:
1 server - 1 site.
e.g. www.computing.dcu.ie
- normally gets 10,000 to 15,000 page views per day.
1 server - n sites.
Common in hosting company. Sites have low to medium traffic.
Many customers may have almost no traffic.
A single powerful physical server can handle them all.
If not, split them up more.
Hosting company periodically adjusts load as traffic changes.
e.g. My website
can get 5,000 page views per day.
But it it still on a shared server:
"1,915 other sites hosted on this server."
I suspect it is one of the larger sites on the server.
90 percent of them may be very low traffic.
n servers - 1 site.
e.g. proxy.dcu.ie.
Switches between 3 machines randomly.
Or, on a larger scale, google.com.
The web address is is actually a gateway or router to many
(maybe thousands of) computers.
Some terms:
Server farms
- Large bank of machines that serves huge number of clients per second.
Typically uses duplication
and is robust to multiple failures.
Often connected direct to backbone.
Carrier hotels
- Backbone operators rent space for server farms
in same room as backbone router.
Servers: maybe 450,000 servers, each a simple PC running Linux.
Location: distributed worldwide.
Google's parallel "Internet".
Google servers run on
their own custom
web server software,
and their own
custom
distributed file system.
Internet Archive
has far less users, but massive 4.5 petabyte database.
Servers: 63 server clusters, each a powerful Sun server running Solaris.
Location: all in a single shipping container
on Sun's campus in Santa Clara, California.
Server farm.
Front end routes HTTP requests to different nodes.
Each node is a powerful server with a full copy of the website.
The movie
The Social Network (2010)
about the invention of Facebook.
The movie may be
semi-fictional
for dramatic purposes,
but there's still only one hero.
Everyone else talks,
but
Mark Zuckerbergcodes.
He builds the stuff, and makes it work.
Every programmer should see this movie.
This movie will make you want to stop talking about your idea
and just code it!
And how much fun is it to see a movie that features PHP and
wget!
On Internet since 1987.
