O.K.,
so we all know that there
are literally billions of
Web pages out there right.
The question is, how do
we find what were looking
for with all those pages
out there? Well, the key
to finding information or
at least the right direction
to head is in learning how
search engines and directories
work. In this article we
will examine just how they
work.
What
are Search Engines/Directories
Anyway?
You
may know that search engines
and directories are tools
that have been developed
to help users navigate through
much of the information
that is out there on the
Information Superhighway.
But you may not know how
they actually work. The
following is a brief outline
of what goes on behind the
scenes.
Search
Engines
Search
Engines are hard working
software programs that explore
the Internet and build indexes
of available pages. These
pages are then made available
to users. By using these
search tools you can quickly
find those resources or
products that are relevant
to you. Search Engines get
their name from the software
that searches through the
indexed databases it creates.
These indexes are special
Web documents which can
be searched rather than
read. The results of such
a search are displayed in
another Web document containing
links to the documents found.
How
Do Search Engines Work?
Search
engines consist of three
parts: A Spider, the Index,
and the Search Software.
The
Spider: The Spider, also
called "the crawler",
visits Web pages to build
an indexed database for
the search engine. Most
engines run several spiders
that explore the Web as
a team. The crawler looks
for new Web pages or changes
in existing ones to place
in it's catalog. The number
of Web pages visited and
how often varies from engine
to engine, but the typical
crawler visits several million
Web pages a week.
The
Index: The Index part, also
called "the catalog",
is where the spider stores
what it finds. Most engines
contain only a text copy
of every Web page visited,
and removes often repeated
words such as "the"
or "an" to save
space.
The
Search Software: The Search
part of the engine is software
that allows you to look
for pages containing information
in response to one or more
key search words that you
have entered related to
what you are looking for.
It then displays the results,
called "queries,"
ranked by a method that
usually involves the location
and frequency of the matching
search words within the
Web pages themselves.
Any
given search usually results
in several hundred to several
hundred-thousand possible
relevant Web homepage that
matches your search inquiry.
If this sounds complicated
it's really not. A search
engine will list the top
ten to twenty Web sites
out of the results for you
with direct links to those
pages.
Search
Directories
Search
directories on the other
hand are different from
search engines. A search
engine finds Web sites on
their own, automatically,
but a search directory depends
on people who operate the
site to submit Web sites
manually. But that's not
all, other people are then
required to classify them,
and then, you get to select
from the listing. The only
downfall for directories
is that search engines find
Web sites automatically
that directories might not
know about. Directories
may also suffer from outdated
or broken links, but usually
more often turn up excellent
and relevant helpful search
results.
Yahoo!
is an example of an excellent
search directory. Most people
think that it is a search
engine because it's a major
guide to the Web. In reality,
Yahoo is a directory that
contains more than a million
listings, categorized far
more efficiently than a
search engine could ever
do.
http://home.earthlink.net/
by Ruben Flores
