A Beginner's Guide to the Internet/INTERNET.ISO/text/guides/help/tools.hlb

Text File | 1996-05-06 | 14.4 KB | 262 lines

Here, There, and Everywhere...

    First, we'd like to give you an overview of your connection to
the Internet.  When you dial up Exec-PC here, you are connecting to a
computer run by Exec-PC.  All of the Exec-PC Internet users are on the
same computer.  This differs from the main Exec-PC system, where each
user is logged into their own computer.
    Currently, the Exec-PC Internet system is an "SparcServer 690"
computer, made by Sun.  This computer is running the Unix operating
system, as opposed to DOS, which is the operating system most PC users
run.  Unix is a multi-user, multi-tasking operating system developed
in the late 1960's by a group of engineers at AT&T Bell Laboratories
for use on DEC minicomputers.  Since then, it has grown to be one of
the most popular operating systems in the world, and is the operating
system that is run by the majority of the computers that are connected
to the Internet.
    So, what does all this mean to you?  Well, it means that there
is a layer in between you and the Internet.  This computer gives you a
place to store files and information, as well as providing the
software and connections needed to allow you to use the Internet.  Why
is this needed?  Well, it means that all you have to do to get to the
Internet is run a communications program on your computer and call up
Exec's system (which you have, obviously, already done).  If you were
connecting to the Internet right from your computer, rather than
through this machine, you would have to have a LOT of software and
hardware on your machine to support your connections to the Internet.
Also, this machine is here, running 24 hours a day.  If you were
connecting directly, you would have to have your computer running and
connected all the time.  Otherwise, what would happen if someone sent
you mail while you weren't connected?  You wouldn't get it.
Fortunately, we take care of that for you.  Whenever you want to get
to the Internet, just call up!
    Now, if you understand that this computer (earth.execpc.com,
or just "earth") is where all your Internet work originates from,
you'll have a good understanding of the Internet tools.  For instance,
if you want to get a file from the Internet, you will first find out
where it is located, then connect to the remote computer on which the
file resides.  At this point, you will tell that remote computer to
send the file to you.  However, the file will not be coming to your
computer.  Rather, it will be sent back and stored on "earth".  When
the transfer has finished, you will disconnect from that remote
computer and tell "earth" to send the file to you, which will begin
the transfer to your computer.  This last step is much the same as
downloading a file from Exec-PC.
    Now, let's take a quick look at some of the tools and concepts
you will use on this system.

The Shell

    You may have heard the term "shell" before, but perhaps you
don't know exactly what it means.  A shell is a program that takes
input from you, in the form of commands, and does what you tell it.
You can imagine the computer and all of its services as being "inside"
the shell.  The shell helps protect you from the nitty, gritty details
of the computer's operation, and gives you an interface to the
services that the system provides.
    The Unix system comes with a basic shell called "sh".  This
shell does everything a basic user needs.  However, we also offer a
more advanced shell on this system called "csh", or the "C shell".
The C shell is a little more advanced, and it offers some features
that the basic shell doesn't.  By default, all users are given the C
shell to work with.  There are also a couple of other shells available
on this system, but a great majority of the users here will never need
anything other than the C shell.

Files

    You are probably already somewhat familiar with files and
directories, based on your experience with your own computer.  Under
DOS, files are located in directories on disks.  Disks (either hard
disks, which always stay in the computer, or floppy disks, which can
be removed and transported) are labeled with letters.  The Unix file
system has some similarities to DOS's file system, but it also has
some major differences.
    Under Unix, there is just one big disk drive.  There are no
removable disks, like floppy drives, and there are no drive letters.
The Unix file system is large, with many different areas.  There are
several "public" areas, which are open to all users.  These areas
contain programs and data which all users need access to.  For
example, the program that displays the menus you see when you login is
stored in a public area.
    Each user also has a private area on the Unix system for
storing files that belong to them only.  This area is based on the
user's "home" directory, which is the default directory that you start
in when you login.  The user may build a directory structure
underneath this home directory to store their files.
    One concept that is important on a Unix system, which you may
not be familiar with based on your experience with DOS, is the concept
of security, access, and permissions.  When you use your computer,
generally, you, and perhaps a few others, are the only users.  Thus,
you needn't worry about protecting your data from prying eyes, aside
from making sure that someone doesn't just walk up to your computer
and start poking around.  With a large, multi-user machine such as
this, however, security is a big concern.  To ensure that files can
only be read and written by those who should read and write them, the
Unix system provides a system of security.  The most obvious part of
this system is the password.  When you login to this system, the
computer asks you for a password to verify who you are.  Once the
computer receives the correct password, you have access to all the
files and resources that are available to your account.  The other
main part of this security system is that of "permissions".  Each file
within the Unix system has a set of permissions that determines who
has what access to the file.  Permissions can get to be a complicated
topic, so we will leave it at that for now.  We'll talk more about
permissions and security in the appropriate area of the help file on
common commands.

Files on the Internet

    Having covered a little ground on files in the Unix system,
let's now talk about files on the Internet.  One of the biggest uses
of the Internet is finding and retrieving files from remote locations.
There are three main tools used for this task: Archie, FTP, and file
transfer programs.
    Archie is a tool used to locate files on the Internet.  Unlike
Exec-PC, where all the files are located in one place, files on the
Internet are located on numerous machines scattered around the world.
This makes it difficult to locate the file you are looking for.
Fortunately, the operators of many of the systems that archive files
have agreed to help maintain lists of what they have on their systems.
There are a little over a dozen archie servers that collect the lists
of files from all the sites.  On this system, we have a program that
automatically makes the connection to an archie server and performs
the query for you.  You simply tell the program what you're looking
for, and it will come back with a list of files that match your
request, and where you can get them.
    FTP is a program used to transfer files between computers on
the Internet.  Its name is an acronym for File Transfer Protocol (who
would've guessed, eh?).  This program is much like the file transfer
protocols you use to upload and download files to and from a BBS,
except that it works over the Internet.  Once you have found out where
a file that you want is located, you connect to the remote computer
and request the file using FTP.  This will transfer the file back to
the computer here (earth).
    The last major program involved in files over the Internet is
your own transfer programs, such as Xmodem, Ymodem, and Zmodem.  These
programs are used to transfer files in between your computer and
"earth".  For instance, once you have found a file on the Internet and
transfered it back to "earth", you will use a transfer program to get
it to your computer.  Most often, these transfer programs are built
into the communications software you are using.

Information on the Internet

    Another task the Internet is used for is finding information.
There are three major tools used for this.  They are the World Wide
Web information system, the Gopher information system, and Usenet news
forums.
    The World Wide Web (WWW) is a system based on the idea of
"hypertext", or text which contains interactive references to other
locations.  You start up a program which allows you to interface with
the WWW system, and you can then read all sorts of information, which
is often embedded with links to other locations with relevant
information.  The beauty of this system is that it allows you to
browse information on numerous systems without you having to worry
about where the information is located.  All of the links are set up
and maintained for you.
    The Gopher system is similar to the World Wide Web system.
Gopher is, simply put, a menu interface to the Internet.  When you
start up Gopher, you will be presented with a menu that lists a number
of options.  By selecting various options, you will work your way
through a series of menus which can lead to all sorts of places.
Various menu options will: display other menus, display information on
a particular topic, log you into a remote machine, or even transfer a
file back to your directory on "earth".  As with the World Wide Web,
Gopher gives you access to a wealth of information without having to
worry about where the information is located.
    Usenet news forums are a form of public message swapping on
particular subjects.  There are literally thousands of forums on all
sorts of topics.  All of these forums allow you to read messages from
people all over the world, as well as letting you respond with your
own views, questions, or contributions.

Electronic Mail

    Electronic Mail, or E-Mail, is probably the most popular
feature of the Internet.  Now that you have an account that is
connected to the Internet, you can send and receive messages to and
from people all over the world who have access to the Internet.
E-Mail is fast becoming a very popular way to communicate and exchange
information.
    The most important thing to know about E-Mail is addresses.
An E-Mail address is how you tell the computer where to send the
message you've written.  Your address starts with the login name you
chose when you registered here.  Your full address will look something
like this:  [e-mail]   The portion of the address after
the "@" symbol is the address of the computer you're on right now.
This is where we get the name "earth" for this computer.
    Electronic Mail is a feature you'll be using a lot as you work
with the Internet.  You can find out more about it in the help file
that is located in the Electronic Mail menu of the menu system.

Remote Logins

    While a network that can transfer files and messages is
useful, it is even more useful if it allows the user to do things from
far away that they would normally have to be right at a computer to
do.  This is the concept behind remote logins.  There are two programs
that are used for logging in remotely.  They are rlogin and telnet.
The programs are very similar, but have a few differences.
    Logging in remotely basically allows you to do many of the
same things that you could do if you were located right at the
computer you're logging into, but from a different location.  Most
often, remote logins are used by people who have accounts on several
machines on the network.  They dial up or connect locally to one
machine, then connect accross the network to other machines.  You may
also login to other machines accross the Internet in order to take
advantage of services offered by those machines.  For instance, the
Library of Congress offers a service where you can login to one of
their computers and search their extensive catalog of books and other
publications.

Editors

    One of the tools that you will probably use quite a lot on
this system is the editor.  You will probably use an editor, most
often, to type in messages to be sent to others.  As you become more
advanced, you will use editors for other things.  For instance, the
people who keep this machine running use editors to edit programs that
run on this machine.  In fact, these help files were created using an
editor on this machine.
    Editors can be very simple, or very complex.  The three main
editors that are provided on this system are pico, joe, and emacs.
Pico and joe are both fairly easy to use, and are good for beginners.
Emacs is slightly more difficult to use, but is VERY powerful, and is
used by many experienced users.

So, how do I use this system?

    That's a big question.  For starters, most users will do just
fine using the menus that we've provided.  On nearly all the menus,
there are help files that describe how to use the commands on those
menus.  As you become more experienced, you may eventually start
entering commands at the system prompt.
    There is another help file that describes how to use many
common commands at the prompt.  However, we'd like to describe a
couple of commands right now.  The commands are "man" and "apropos".
These files provide access to the on-line documentation of Unix
commands.  If you want to find a command to do a specific task, type
"apropos topic", where topic is a single word that relates to the task
at hand.  This will generate a list of all the commands that relate to
that topic.  Be warned, however, that you will often get commands that
do not neccessarily relate to the topic you had in mind, as the word
you enter can often have several contexts.
    The other command, "man", displays more detailed information
on specific commands.  Just type "man command", and you will be
presented with the first page of information on that command.  Press
the space bar to move onto the next page of information, until you
reach the end of the file.  For more information on how to view this
information, see the section on "more" in the help file on common
commands.

    Well, that about wraps up our overview of tools and concepts
on this system.  Now, we suggest that you take a look at the help file
on common commands, to get a better feel of how to go about certain
tasks on the Unix system.
    As always, if you have a question on how to use the system,
you can send mail to "help" on this system.  However, please try to
find the answer to your question in the help files first.  ("Help" is
a very busy guy!)