Using
The Internet
Browsers
Browsers are tools your computer uses to access
the internet. They read the data that reside on sites on the internet, and translate
it into the images and sounds that you receive. Good, effective use of all the
internet has to offer, depends on having a good browser. There are several
types of browsers, but the two most popular are Netscape and
Internet Explorer. Both are very good browsers with many appealing functions, but in
my humble opinion Netscape is the one to go with. I have tested the latest versions
of Netscape and Internet Explorer, and have found Netscape to be the easiest and most user
friendly one out there. You should try both of them and decide which one you are
most comfortable with, and which one performs the way you need it to. The latest
versions of both of these browsers are available to download for free. I never did
understand why someone would go to the store and buy them. To download the latest
version, click on the browser of your choice below and follow the instructions.
Helpers and
Plug-In's
Technical Explanation
The Web is so good at displaying so many types of
data that people often assume that Web Browsers and Servers simply know everything. This is
clearly not possible. Under current HTTP, the server begins every response to a Browser by
declaring that the following data to have a particular format. The standard represents
data formats by a MIME type. MIME is an internet standard originally developed for E-mail.
It declares a major type (text, image, application) and a minor type. For example:
text/plain is ordinary unformatted text
text/html is Web-formatted text, like this page
application/pdf is a page formatted by the Adobe
Acrobat software
Data type is not an attribute of files in either
Unix or the Windows NT directory structure. So generally, the Web Server guesses the right
MIME type based on the file "extension" (the part of the file name after the
last period). A Microsoft IIS Web Server uses the mapping of file extension to mime types
configured in the "Classes" section of the operating system Registry. A Netscape
Web Server is configured by files in its /usr/local/ns-home/httpd-hostname/config or
\netscape\server\httpd-hostname\config directory. The "mime.types" file contains
a list of MIME types and their associated extensions:
type=application/pdf exts=pdf
type=application/postscript exts=ai,eps,ps
type=application/rtf exts=rtf
It is also possible for the Browser to make a
guess about the type of data based on the extension of the file. However, the Browser
will make such a guess only when the file is fetched using FTP or some other protocol. A
Web Server is supposed to send a MIME header, and then the Browser will defer to the
server's best guess.
A Browser can display plain text, HTML, and
several popular image types (GIF, JPEG). The browser may also be able to play audio files
(*.AU or *.WAV). More exotic data types are supported through a Helper or Plug-In.
A Helper is an external program that knows
nothing about the Web. Any program can be a Helper. When the Browser is about to receive a
file whose MIME type is not internally supported by the Browser itself, it looks the type
up in a table. If a Helper program is configured for that type of data, then the file is
received into a temporary directory and the Helper program is launched as a separate
Windows application to view or play the file.
A Plug-In is a program that was written
specifically to communicate with the Netscape Navigator Browser (or any other Browser that
supports the Plug-In interface). A plug-in is packaged as a DLL in Windows and a Shared
Library file (*.so) in Unix. It is installed in a subdirectory of the Netscape Browser and
is loaded into memory when Navigator starts. If a file is received with a MIME type
associated with one of the Plug-Ins, Navigator calls functions in the Plug-In shared
library display or play the file inside the current Navigator window. Plug-In modules
extend the set of file types for which Navigator appears to have standard internal
support. A Plug-In library is generally written in C or C++. It functions as ordinary code
that is part of the Browser program. Unlike Java Applets, which are constrained by a
security policy, a Plug-In can access disk files, open network connections, run other
programs, and issues commands to the operating system. The user must first obtain and
install the Plug-In before it can function, and the assumption is that a user will use the
same care installing this code as he does any other program.
Easy Explanation
Some sites, such as virtual tours, require a
plugin. A plugin is simply an application that your browser uses to open and play
certain files. For instance, for audio, you might need a plugin such as Real Player.
For animated scenes, you might need Shockwave. These two plugins can be
downloaded for free. Just click on the button below to begin downloading.
With Netscape, Shockwave, and Real Player you
should be ready to surf most of the fun interactive sites. The internet is also a
great place to get free software, free educational games, free clipart, and much more.
I will tell you where to go to get these free items later, but first let's make sure
you have all of the tools.
HTTP
Technical Explanation
The HyperText Transfer Protocol (HTTP) defines
how the Browser sends requests and how the Web Server replies. It is a very simple system
in which all the data is sent as plain character text. The Browser generates a
request when the user types in a URL or clicks on a phrase or image linked to a URL. The
URL contains the protocol name ("http:"), a server name
("pclt.cis.yale.edu"), and the name of a resource
("pclt/default.htm"). Most of the time, the resource is a file, but it is up to
the Server to figure out what the name means. The HTTP rules tell the Browser to establish
an Internet connection to the Server named in the URL. The same machine may provide many
services, each identified by a port number. The default for a Web Server, if no other value
is specified, is to use port 80.
The Request
The Browser then sends a request in the form of a
stream of ordinary text. The first line of text contains a verb (usually "GET"
or "POST"), the resource name("pclt/default.htm"), and the version of
the protocol ("HTTP/1.0"). Subsequent lines contain "header
information" in the form of an attribute name, a colon, and some value. The request
ends with a blank line. Header lines are optional, but a typical request from a modern
browser might have the form:
GET pclt/default.htm HTTP/1.0
accept: image/gif, image/x-xbitmap, image/jpeg,
image/pjpeg, */*
user-agent: Mozilla/3.01Gold (WinNT; I)"
connection: Keep-Alive
The "accept" header indicates that when
an image is available in more than one format, the browser would prefer to receive it as a
GIF or JPEG file. The "user-agent" header identifies the Browser as Netscape
Navigator 3.01 running under Windows NT on an Intel machine. The "connection"
header offers to obey the "keep-alive" protocol, where the network session is
reused for subsequent requests.
Other headers can specify the preferred language
(French, Spanish, English) for documents, or provide the timestamp of a previous copy of
the file that the Browser holds in its cache, suggesting that the file be resent only if a
newer copy is available.
The Server receives this request and extracts the
resource name (pclt/default.htm) from the first line. The resource could be the name of a
file, which the server will read off disk and send back to the Browser. Or the resource
could be a program, which the Server will run and then send the program output back to the
Browser.
The Response
HTTP defines the format of the Server response to
be similar to the original request. Again the first line has three fields, but now the
protocol comes first instead of last. There is also a status code and status message.
Again, there are optional header lines, each with an attribute name, a colon, and an
attribute value. The headers end with the first blank line. This is immediately followed
with the data from the file or the output from the program:
HTTP/1.0 200 OK
Server: Netscape-Communications/1.12
Last-modified: Friday, 23-Feb-96 14:54:39 GMT
Content-length: 88
Content-type: text/plain
This is a simple text file placed in the first
document directory of the PCLT server.
A response code of 200 means that the request was
processed normally. Codes in the 30x range indicate that the resource name cannot be found
or the resource has moved. Codes in the 40x range generally indicate that you are not
permitted to view the resource. Codes in the 50x series indicate a programming error in the
Server.
The "Content-type" header provides the
MIME code for a particular type of data. Here the "text/plain" code means that
the file is ordinary unformatted text. The most common type is "text/html" for a
formatted Web document. A Web server can use HTTP to send images, audio, compressed
archives, Java classes, or any other type of data. The response begins with the status
line and header lines in plain text, but after the first blank line that ends the headers,
the rest of the response can be 8-bit binary data.
If the Server provides a
"Content-length" header line, then the Browser knows exactly how many bytes of
data to read. Various extensions of HTTP 1.0 will use this information to keep the
Internet session active so that a new request can be sent over it. If the Server is unable
to provide the length of the data, then the Browser must read bytes until the Server
indicates the end of the data by terminating the session (so the Browser gets an "end
of file"). A new request will then require a new session.
This is important because few HTTP operations
involve only a single exchange. A formatted Web document can contain HTML references to
image files that provide illustrations, icons, or even background patterns. It can also
have references to Java Applets, which may in turn require additional Java Class files to
execute. A Microsoft Browser may contain references to an ActiveX object. After the
initial HTML file is loaded, the Browser will come back to the Server to load any files
required by these embedded references. If the session can remain alive and be reused, this
sequence of downloads will be faster.
Running Programs
The resource named in the HTTP request may refer
to a program. HTTP does not specify how the Server determines this. In some cases, there
are special directories that contain only programs. It is a convention that
"cgi-bin/" is a dummy directory that contains ordinary executable programs,
typically written in C or Perl. The Netscape Server reserves a special dummy directory
name "server-java/" for Java programs that run on the Server. In other cases,
the Server decides based on file type. The Microsoft IIS server recognizes a file with a
"*.DLL" extension as an ISAPI program, while a file that ends in
"*.ASP" is an IIS 3.0 Active Server Page, an HTML file that may contain embedded
VB Script or JavaScript programming.
No matter what type of program the Server decides
to run, the only information available is going to come from the request text stream.
Primarily, this means the resource name in the first request line, and the header lines
that follow. There are two additional fields, however, that are frequently used to
communicate information to a Server-side program.
A string of program parameters, commonly called
the "query string" can be appended to the program name following a "?"
character. The only constraint that HTTP places on the format of this string is that it
cannot contain blanks. There are two conventions that suggest its possible format:
In the "CGI" convention (described in
detail later), the query string is passed as the first command line parameter to
the program. In HTML "Forms" (also described later), the query string
contains a sequence of varname=value pairs separated by "&", as in
Name=Figaro&Occupation=Barber".
On many systems, the query string is limited to
255 characters. When more data must be passed to the program, an alternative is provided
by the POST protocol. POST is an alternative verb, replacing GET on the first line of the
request. POST indicates that the request contains additional input data. To use POST, the
request must contain a header line with the same "Content-length" field
specified in a typical reply. As with the reply data, the "Content-length" in
the request indicates the number of bytes of (possibly binary) data that follows the first
blank line ending the sequence of header lines. There can also be a
"Content-type" field indicating the format of this data. Again there are two
conventions that suggest, but do not require, a particular use for this data.
In the "CGI" convention, POST data is
passed as the standard input file to the application program With HTML "Forms",
the data contains varname=value pairs and the Content-type is
"application/x-www-form-urlencoded".
A program could be written to accept data in any
format. One could imagine the use of POST data to carry a SQL query to a database:
POST /dbms/query.exe HTTP/1.1
content-type: text/plain
content-length: 117
SELECT name, day, start_time, length, channel
FROM tv_program_table
WHERE type="SITCOM"
ORDER by day, start_time
Semi-Stateless
Any Keep-Alive convention to reuse the same
session for more that one request doesn't change the basic HTTP model that every request
and response stand alone, independent of previous or future exchanges. A Web page can
point to many different documents and programs on many different servers. When a program
runs on a Web Server, it cannot make any assumptions about how the Browser came to make
the request.
Netscape proposed, and the industry has generally
accepted, a tool to provide a small amount of history. It is the "cookie"
protocol. A Web Server can include a "Set-cookie:" header in any HTTP response.
The cookie data consists of a sequence of varname=value pairs separated by semicolons. The
Browser stores this information in a disk file, and returns it as a "Cookie:"
header field in any subsequent request directed to another program in the same directory
of the same Web Server.
Since the cookie information is stored in a disk
file, it can be viewed, altered, or deleted by the user. This is not a safe place to store
sensitive information. However, it can provide some history, and it can hold information
so the application doesn't have to ask the user the same silly questions over and over
when he revisits the site. It can also hold a customer number or other ID field that can
be used to locate information in a Server-side database, where the application can
securely store information that the user cannot alter.
Easy Explanation
It really doesn't matter. It works and that
is all I care about. Ignorance really is bliss sometimes :)
File Transfer Protocol
(FTP)
What is FTP?
File Transfer Protocol (FTP) is a protocol used
to transfer ASCII or BINARY files between two computers on the Internet. The primary
function of FTP on the Internet is in the use of anonymous FTP sites. An anonymous FTP
site is simply an Internet site accessed via FTP that has a large number of files
available for downloading. They are called anonymous because you login anonymously. Simply
enter the word anonymous at the "Name:" prompt and your full e-mail address at
the "Password:" prompt.
Some anonymous FTP sites are small, consisting of
only a dozen or so files related to a specific topic. Others are huge shareware archives
with thousands of files. It should be noted that the increasing influence of the World
Wide Web has resulted in most file archives being available over the Web, as well as FTP.
FTP Clients
To directly access an FTP site on the Internet,
you will need some kind of FTP client. While most Web browsers have built-in FTP clients,
stand-alone FTP applications also exist. Having such an application is an advantage if you
don't like waiting for your web browser to load when all you want to do is access an FTP
site. In my opinion, the best FTP client is Cute
Ftp. You can download a free trial version by going to their site.
Archie File Search
Because there are so many anonymous FTP sites on
the Internet, it would be impossible for you to search through each one individually in
hopes of finding the file you want. To assist you in your file search, a service called
Archie is available. Archie is a public search engine whose database currently maintains a
list of about 900 Internet anonymous FTP sites of approximately 2.1 million files
containing 170 Gigabytes (170,000,000,000 bytes) of information.
There are many Archie servers throughout the
world that can be accessed either by e-mail or telnet. None of these servers actually
store all of the files available via anonymous FTP. Instead, they simply keep track of the
directories and filenames located at each anonymous FTP site.
Types of Searches
Name Searches
To perform a name search, simply give Archie a
search string (there are four search formats, discussed below). Archie will then list all
FTP sites that have the word(s) you're searching for in their directories or filenames.
For example, if you searched for the word "equestrian," you might receive the
following result:
Host plaza.aarnet.edu.au
Location: /usenet/FAQs
DIRECTORY drwxr-xr-x 512 15-May-1996 16:53:25
rec.equestrian
Host sun.rediris.es
Location: /docs/faq/rec
DIRECTORY drwxr-xr-x 512 05-Mar-1996 15:07:17
equestrian
Host ucdavis.ucdavis.edu
Location:
/pub/U.C.Davis.directory/Campus.Departments.and.Offices/E
FILE -rw-r--r-- 122 29-Oct-1995 10:44:02
EQUESTRIAN.CENTER........................................752-2372
We now know that what appears to be a UseNet FAQ
for the newsgroup rec.equestrian can be downloaded via anonymous FTP from the FTP site
plaza.aarnet.edu.au, among others. The third result (from ucdavis.ucdavis.edu) appears to
be part of an e-mail directory.
As previously mentioned, there are four ways of
entering a search string for an Archie name search. A brief description of each is as
follows:
search substring - Simply enter one or more words
to be found anywhere in the Archie
database (either as a filename or directory)
search substring (case sensitive) - Same as above, except this search will only
produce results that match the same case (capitalization) as the entered search string.
exact - Use this option if you already know the
exact filename of the program you're looking for. Archie will search only through
filenames for an exact match. This is the fastest search, but it is only useful if
you already know exactly what you're looking for.
regex - This stands for Regular Expressions,
which is a complex system within Archie that
allows you to use certain characters and syntax
to "mold" your search to yield specific results.
A complete guide to using Archie Regular
Expressions is available.
File Description Searches
Archie maintains a Public Domain Software
Description Database, which contains descriptive information about the actual content of
some files (mostly text files) that can be downloaded via anonymous FTP. This type of
search is most useful if you're trying to find information about RFC's, Unix utilities, or
technical Internet documents.
Site Searches
Two commands fall under this category. The list
command results in a list of all anonymous FTP sites currently in Archie's database. The
site command produces a list of all files known to Archie for a specific FTP site.
How to Access Archie
There are many Archie servers located throughout
the world. Each can be accessed several different ways. You can perform an interactive
Archie search by logging into an Archie site via telnet or by using an Archie client. A
remote Archie search can be done by using e-mail. Each of these methods is discussed
below:
Archie Client
This is perhaps the easiest way of using Archie
for anyone with a SLIP/PPP Account. An Archie client is a piece of software that
automatically telnets to your favorite Archie server, enters the proper commands, and
neatly displays the results on your screen. Most programs allow you to automatically
download any file in the Archie result screen using your FTP Client.
Telnet to Archie
Accessing Archie via telnet is probably one of
the most difficult ways of getting things done, but a brief explanation of how to go about
it has been included just in case. The first step is to telnet to one of the Archie
servers. A good rule of thumb is to pick the one that is geographically closest to your
location. Once you are connected to the server, simply enter the word archie at the login
prompt (login:). No password is necessary. You will then receive a prompt that looks like
this: archie:.
The appearance of this prompt marks the beginning
of your interactive Archie session. At this point, you can enter any of the commands
accepted by Archie. Although a complete Archie operation manual is available, a brief
summary of the essential commands is listed below:
find <pattern> - Where <pattern> is
the word(s) you want to search for within the Archie
database. Will result in a list showing the
filename, directory, and FTP site where each match
can be found. The find command can be used with a
searchable substring (optional case
sensitive), exact pattern, or regular expressions
(see above).
help <topic> - Initiates an Archie help
session.
manpage - Produces the entire Archie operating
manual. (very long!)
Accessing Archie by E-Mail
Because Archie is used quite frequently by the
Internet community, you will often find that using Archie interactively is rather
sluggish. This is because you are always in line behind others trying to use the same
Archie system. So, let's say you just want a quicker way to search Archie's database. Or,
perhaps you only have access to e-mail and can't use Archie using any of the other
methods. There's a simple solution to both of these problems -- access Archie by e-mail!
All you have to do is simply send an e-mail
message to the Archie server of your choice, and the next time you check your e-mail (the
process usually takes a few minutes, although it can sometimes take as much as a day), you
will have an e-mail message from Archie with all the results from your search.
To use Archie via e-mail, follow these steps:
I.Address a new e-mail message to
archie@<Archie server> (where <Archie server> is the address of any of
the Archie servers - i.e. archie.au).
II.Leave the subject line blank.
III.Use any Archie commands in the body of the
message. Hint: To simply search the Archie database for one or more words, use find
<pattern>, where <pattern> is the word(s) that you want to search for.
IV.Send the e-mail!
V.You should receive a reply from the Archie
server within a few minutes, although it can sometimes take as much as a day.
This process is done using a listserver and is
completely automatic. In other words, no humans are involved in this process, so any
problems you encounter are due to problems with the Archie server. A complete list of
Archie commands that can be used is available.
Search For Anonymous FTP Sites on the Web
With the increasing influence of the World Wide
Web on the Internet, many anonymous FTP sites now have their entire file archies available
on the Web. Most of these also have easy-to-use search engines that search file names and
(sometimes) file descriptions for an entered search pattern. A useful service called
Shareware.com (http://www.shareware.com) can be used to search several of the existing
on-line FTP sites at once.
Gopher
What is Gopher?
Gopher is an Internet protocol
developed at the
University of Minnesota that organizes information on the Internet into an easy-to-use
interconnected menu system. Within a single Gopher server, Gopher menus are hierarchical.
That is, there are distinct levels within the menu system, the "Main Menu" being
the top level. Menu items can be links to many things. They usually lead to another Gopher
menu or a text file. A menu item can also connect you to another Gopher server, access an
FTP file, or initiate a Telnet session with another computer. The fact that one Gopher
menu item can connect you to another Gopher server is what makes the Gopher system
interconnected. The large network formed by these interconnected Gopher servers is often
called Gopherspace.
With the increasing popularity of the World Wide
Web, Gopher is not used quite as much as it used to be. It still has its advantages,
however. Because Gopher menus present text information in such a convenient fashion, many
organizations host on-line libraries or reference systems on Gopher servers. You can also
find most on-line reports published by the U.S. government (as well as other governments
and international organizations) in Gopherspace. Commercial groups tend to put their
businesses on the World Wide Web, instead of Gopherspace, because of the Web's multimedia
capabilities (incorporation of graphics, sound, etc.).
Accessing and Using Gopher
If you have a SLIP/PPP account, chances are that
you probably spend most of your time on the Internet using the World Wide Web. If this is
the case, you should know that most Web browsers can access Gopher menus and documents.
The URL protocol prefix for a Gopher item is simply gopher://. When most browsers
encounter this prefix, either when manually entered or selected as a link, they
automatically load an internal Gopher client that can "read" Gopher menus and
documents. Special stand-alone applications called gopher clients also exist, as an
alternative to always using your web browser to view gopher documents.
Gopher Addresses
Gopher addresses consist of three parts:
the Gopher server name
the port
the path
The Gopher server name is simply the domain name
of the computer hosting the Gopher site. For example, the Gopher server name of the
National Archies is gopher.nara.gov. The port is a number that directs your Gopher
software to a specific document on the Gopher server. It is sort of like an extension
number within an office switchboard system. You can call the business directly, or you can
enter an extension number to talk to a specific person or department. The default port
number is 70. This is where most Gopher servers have their "Main Menu." Over 90%
of the time, you will not need to enter a port number. But, it's always good to know how.
With most Web browsers, Gopher ports are entered
with a colon (:) separating the Gopher server name and the port number, like this:
gopher://gopher.nara.gov:340
Notice this URL's protocol prefix, gopher://. This
prefix must be entered with the URL in order to access a Gopher item from within your Web
browser. It takes the place of the familiar http://. If you are using a separate Gopher
client application, a "Connect" dialogue box will probably have a separate entry
box for the port number. Just remember that the default port number is 70 and unless a
specific port number is given, don't change the default port number.
The last part of a Gopher address is the path.
You only need to enter a path if you want to access a specific Gopher item directly
without having to weave your way through all of the menus that come before the desired
document. For example, The FineArt Forum is located at the Gopher server
gopher.msstate.edu. If you entered only the server name, you would have to go through a
couple of menus before actually reaching the FineArt Forum. This is where the path comes
in. The path is simply the "path" of menus (actually directories on the Gopher
server's computer) that must be followed to get to the desired Gopher item. The full
address (path included) of the FineArt Forum is this:
gopher.msstate.edu/1/Onlineservices/fineart_online
Notice the forward slash (/) separating each part
of the path.
Gopher Bookmarks
Virtually every Gopher program has a feature
called bookmarks. Bookmarks are simply Gopher items (directories, documents, or search
boxes) that you use frequently and "bookmark" by saving the item's Gopher
address and description on your computer. Most Gopher programs allow for easy saving of
"bookmarks" and allow you to access bookmarks in the form of an easy-to-use
menu. Read your Gopher program's help documents for specific information on how to
bookmark Gopher items.
Searching Gopherspace with VERONICA
VERONICA, which stands for Very Easy
Rodent-Oriented Network of Indexed Articles, is an easy-to-use search engine that returns
all documents in Gopherspace containing a user-defined search string. VERONICA can be used
to search either Gopher documents or Gopher menus, or both.
VERONICA can be accessed at
gopher://veronica.scs.unr.edu/11/veronica.
Caches and Cookies
This is a repeat of the cookie and cache
section in fine tuning, just in case you didn't read it (slacker!!)
Cookies
What are cookies?
A "cookie" is a small piece of
information sent by a web server to store on a web browser so it can later be read back
from that browser. This is useful for having the browser remember some specific
information.
What are they used for ?
An example is when a browser stores your
passwords and user ID's. They are also used to store preferences of start pages, both
Microsoft and Netscape use cookies to create personal start pages. Common cookies
which companies use are find info are listed below:
Online Ordering Systems.
An online ordering system could be developed
using cookies that would remember what a person wants to buy, this way if a person spends
three hours ordering CDs at your site and suddenly has to get off the net they could quit
the browser and return weeks or even years later and still have those items in their
shopping basket.
Site Personalization.
This is one of the most beneficial uses, let's
say a person comes to the MSNBC site but doesn't want to see any sports news. They allow
people to select this as an option, from then on (until the cookie expires) they wouldn't
see sports news. This is also useful for start pages.
Website Tracking.
Here is a hot button! A lot of people think it is
an invasion of privacy, if a web site
designer wanted to see what interests them.
Site tracking can show you "Dead End Paths", places in your
website that people go to and then wander off because they don't have any more interesting
links to hit. It can also give you more accurate counts of how many people have been to
pages on your site. You could differentiate 50 unique people seeing your site from one
person hitting the reload button 50 times.
Targeted Marketing. This is probably one of the
main uses of cookies, they can be used to build up a profile of where you go what adverts
you click on, this information is then used to target adverts at you, which they think are
of interest, companies also use cookies to store which adverts have been displayed so the
same advert does not get displayed twice. Doubleclick's use of cookies.
User ID's.
In Internet Explorer 3.0 the first part of the
cookie is your win95 log in name, It's not
certain if this is passed on to the server.
How Do They Work
A command line in the HTML of a document tell the
browser to set a cookie of a certain name or value. Here is an example of some script used
to set a cookie.
Set-Cookie: NAME=VALUE; expires=DATE;
path=PATH; domain=DOMAIN_NAME; secure
Cookies are usually run from CGI scripts, but
they can also be set or read by Javascript.
Security?
An HTTP Cookie cannot be used to get data
from your hard drive, get your email address or steal sensitive information about your
person. Early implementations of Java and JavaScript could allow people to do this but for
the most part these security leaks have been plugged. But HTTP Cookie can be used to track
where you travel over a particular site, This site tracking can be easily done without
using cookies as well, using cookies just makes the tracking data a little more
consistent. If you want to disallow cookies you can do so with version 3.0 or greater of
Netscape. Go to the Options Menu Select the Network Preferences Menu Item From the window
that appears Select Protocols Locate the Section Show an Alert Before Check the box
labeled Accepting a Cookie From now on you will get an Alert box telling you that a server
is trying to set a cookie at your browser. It will tell you what the cookie value is and
how long it will last before it is deleted
In the last few months Microsoft and Netscape
have released betas, previews and the final releases of their next version 4 browsers,
there have been a few changes to do with cookies, mainly from Netscape. The latest
browsers are very much into personalizing, the cookie files and the cache directories have
moved and are unique to each user, rather than having a generic directory where everything
is stored. Apart from options on accepting cookies and their location, the cookie format
remains the Same as the version 3 browsers.
Netscape Communicator
Communicator has some of the options suggested in
RFC2109, which aim is give greater control of cookies, the options for cookies can now be
found under the edit menu | preferences... | Advanced Tree |. There is a whole section
under cookies, here is the latest options that the final release boasts:
Accept all cookies; speaks for itself!
Accept only cookies that get sent back to the
originating server; at first this seems to contradict the cookie specs published by
Netscape, which states cookies can only be sent back to the server which set the cookie.
But, it actually means it only accepts cookies which are returned to the domain which you
are logged onto, for example, when you log on to dejanews it retrieves its ad banners from
focalink (a targeted marketing company which uses cookies to gain some demographics on
users), if you have set Communicator to this option it will not accept the cookie sent
from focalink, because it is not returned to the dejanews domain. Very handy for blocking
out third party servers.
Disable Cookies; rejects all cookies by default.
Warn me before accepting a cookie; Displays a
warning box when Netscape encounters a cookie, be warned this becomes very annoying very
quickly.
Internet Explorer 4
There has been very little changes from IE3.
First the cookie jar has moved to c:\Windows\Profiles\<user name>\cookies\ ,
the format of the cookies is the same as IE3, and can be doctored in the same way as the
c:\Windows\Cookies\ can be, again please refer to the stopping cookies section for
information on editing your cookies. Your user name is contrived from your login name, if
using windows login, if not, it uses the registered Windows name. Similar to version 3,
cookies are also stored in the c:\Windows\Temporary Internet Files\ directory, you can
also delete or doctor these.
There is still only the option to warn before
accepting cookies in IE, you can turn this on by clicking on the view menu | Options... |
Advanced tag | Warnings section | and unchecking "don’t warn before accepting
cookies". Again this can be annoying.
Microsoft may be little apprehensive in including
some of the options included in Netscape Communicator. Maybe because some of their Active
Server Pages (asp’s) rely heavily on cookies to operate properly. The early betas of
Internet Explorer 3.0 had such options to stop cookies completely, but these soon
disappeared in the final versions of IE3.01 and 3.02 probably for this reason.
What, and Where is my Cache?
A "cache" (pronounced like
"cash") temporarily stores on your computer the information from web pages
you've visited. If you later revisit a page that is stored in the cache, your browser can
retrieve the page from its cache more quickly than retrieving the page again from its
location out on the network.
The files in Netscape Navigator's
"cache" directory are given cryptic names (such as "cache2093120-2"),
and on Windows they have a ".moz" extension; there may be hundreds of these
files in the directory. Don't bother trying to view or delete any of the files in the
"cache" directory yourself; your browser will use them when it needs to.
If you want to reduce the amount of disk space
the cache files are taking up on your disk under Netscape Navigator 3.0, go under the
Options menu, and select "Network Preferences". Then select the
"Cache" tab. There you should be able to set the Disk Cache to the size most
appropriate for your use. A similar function is available on Internet Explorer.
You can also press the "Clear Disk Cache
Now" button to completely empty out your cache (but it will gradually fill back up to
the "Cache Size" setting as you browse the web). The lower your "Cache
Size" setting is, the less space the cache will take up on your hard disk, and the
more often your browser will have to reload files from the network (slowing it down)
because it doesn't have the files in its cache any longer. (If the cache is full, pages
that haven't been visited for a long time will be removed to make room).
Search Engines and
Directories
The Major Search Engines
For web surfers, the major search engines
generally mean more dependable results. These search engines are much more
likely to be updated frequently and to keep up with all the new pages submitted every
minute. Commonly referred to as "spiders" or "crawlers," search
engines are searching the web for new pages at all times. Because they are automated and
index so many sites, search engines may often find information not listed in
directories. To the flip side, they may also pull up unrelated information for the
topics you're searching for.
Directories:
Directories are created by a person who actually
profiles a site , as opposed to a search engine which uses a 'robot' or 'spider' to do
this. Sites are submitted and then assigned to an appropriate category or
categories. Because someone is actually profiling a site, rather than a 'robot',
directories often provide much more targeted results than search engines.
Combination Search Engines:
Many of the medium size engines have helped
confuse the issue of what the difference is between and engine and a directory by
combining the two. These are search engines that also work in conjunction with a
directory. Usually these are reviewed and rated sites.
Basically, if you are searching for specific
information, it is a good idea to start with directories, like Yahoo or Infoseek Education
directories. However, if you are searching for general information, or information
on a topic that is not well known, your best bet would be to use the major search engines.
Following are links to a few of the available
search engines:
Infoseek
- http://guide.infoseek.com
Excite -
http://www.excite.com
Alta
Vista - http://www.altavista.digital.com
Yahoo -
http://www.yahoo.com
HotBot -
http://www.hotbot.com
Magellan -
http://www.mckinley.com
Open Text
Index - http://index.opentext.net
Downloading
A lot of times, when you want to download
something from the internet, the item is "zipped". This is simply a
compressed form of the program or item. Think of it as a slinky. You can
compress a slinky to make it smaller, and then let it spring back again. This is
what happens to a program when it is "zipped". The person providing it has
compressed it so it takes up less space on their web page, and it makes it faster to
download. To make these programs functional, you must "unzip" or
uncompress them. This can be done with an unzipping tool. The best zipping and
unzipping utility is Winzip...and it can also be downloaded for free.
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