Welcome to Exploring Computing.
Today's video is "Introduction to HTML, Origins of the Web."
So in this video, we're going to take a look at where
the World Wide Web comes from.
I think having an understanding of the background of why
the World Wide Web was created and where it comes from
is going to give you a better sense of what's actually
going on when we take a look at how the web works,
and when you see what some of the limitations are
and some of the oddities involved with the web.
So the World Wide Web comes from two basic technologies.
The first one is the internet, which
we spent quite a bit of time studying over the last couple
of lectures.
And the second one is a technology called hypertext.
And so we're going to start off by taking a look at hypertext.
The basic idea behind hypertext is,
how are we going to present information for people?
And we've been using the book for forever,
and so the question is, what are the limitations of the book,
and what might we want to do to replace it?
And this is a question that information scientists
have been thinking about for quite some time.
And in fact, we started thinking about how
information technology might provide
a good replacement for books right
around the end of World War II.
So there's a famous article by Vannevar Bush
called "As We May Think," and that came out in 1945.
Now, as I mentioned, one of the key technologies behind the web
is hypertext.
The beginnings of hypertext and hypermedia
actually date back to 1963.
Probably the first widespread use of hypertext and hypermedia
were electronic encyclopedias found on CD-ROMs.
Microsoft Encarta, starting in 1993,
provides a really good example of this use of the technology.
And the World Wide Web first came out in 1989,
which you'll note actually precedes Microsoft Encarta.
But it was only in use by a very limited number of people,
and we'll be taking a look at that in a couple of minutes.
All right, so what's wrong with the book?
Why would we want to replace it?
Well, one thing about a book is a book consists of pages,
and each of the pages follows a preceding page sequentially.
I mean, that's fairly obvious, but it turns out
this can be a pretty big limitation.
It really depends on what sort of book we're looking at.
So we have page 1 followed by page 2 followed by page 3
and so on, and we're reading fiction,
this is probably a good choice--
unless, let's say, it's a mystery novel
and you just can't handle waiting till the end,
and so you flip to the end to see what's going on.
Or possibly you're a literary criticism major
and you want to jump around the book.
But most of us are perfectly happy with the linear nature
of fiction novels.
In contrast, think about something like an encyclopedia.
Because an encyclopedia is printed,
it's got that single sequential information flow.
So if we're looking for an article on the Reverend Martin
Luther King, we're likely to find
him sandwiched between King George of England
and King Philip of Spain.
What does he have to do with those two?
Well, the encyclopedia only has one ordering of information,
and it uses that linear ordering of information
to make it easy to look up articles, not to find links
between different articles.
And so when we move to computers,
we're no longer limited to that single ordering of information.
We can create different nodes of information
and link any node to any other node.
So we can still maintain our sequence of information
for lookup if we wanted to, but we could also
link the Reverend Martin Luther King
to articles on the civil rights movement, to Selma, Alabama,
to the great leaders of the 20th century, and so on.
We now have a web of information,
which is where the term "World Wide Web" comes from,
of course.
And this concept of hypertext basically
said that we have these different text nodes,
and that we're going to link the text nodes.
And of course, this is exactly how the World Wide Web works.
We can take things a step further on the computer,
because we're no longer limited to just text.
We can have speeches, we can have audio--
so we can have the Reverend Martin Luther King's
"I Have a Dream" speech--
we can have photographs, we can have movies,
and so this is called hypermedia.
OK.
So that's the basic idea behind hypertext and hypermedia.
But that still doesn't get us to the World Wide Web yet.
That's only half the equation.
We've seen that the other half of the question
is the internet, but how did the two end up together?
Well, we need to move to Europe.
And in Europe there's a physics consortium called CERN.
It has 23 member countries and its main headquarters
in Geneva.
It's most famous for a large collider which
is used for high-energy physics, not that different
from our very own Stanford SLAC.
And in this case they have a 27-kilometer ring
which is used for high-energy physics and smashing particles
into each other.
Now, in the late '80s, one of the computer scientists working
for CERN was interested in coming up
with a way for the physicists at CERN to share research papers.
One of the things that happens at CERN
is the member countries send their physicists to CERN,
and then sometimes they return to their own institutions
in their various countries.
And so he was looking for a way to share papers
between all the physicists.
And naturally, he thought, we should use the internet.
But in addition, he thought, we should use that hypertext
technology that people have been talking about,
and that's been sitting there in the research
lab for quite some time, and nobody's actually using.
If you hear some tinkling in the background,
that is actually Matty drinking from her dog bowl and her dog
tags hitting the dog bowl.
Anyway, so Tim Berners-Lee in 1989
came up with this idea of combining the internet
with hypertext in order to share information between physicists.
And this is the origin of the World Wide Web.
He was knighted for it in 2004.
So I think it's important when you look at the World Wide Web
and you wonder why some of the things
work the way they do in the World Wide Web--
it was originally invented to allow physicists to share
physics research papers, and so it didn't really
have the sort of technologies we might want for widespread mass
media usage.
We'll see that some of them have been tacked on.
But there's still some things that--
I think if you were designing the system specifically
for mass market and for regular consumers,
you might have come up with a slightly different formalism
for how the addresses work.
And we are going to see that there's a lot of stuff that
had to get added in order to provide for much more colorful,
much more interesting web pages than you might expect
to see in a physics paper.
All right, so in the next video we're
going to take a look at HTML, which
is actually the language used to create web pages.
I'll talk to you soon.