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####### ######## ######## ###########
### ### ## ### ## # ### # Interpersonal Computing and
### ### ## ### ## ### Technology:
### ### ## ### ### A Journal for the 21st
### ######## ### ### Century
### ### ### ###
### ### ### ## ### ISSN: 1064-4326
### ### ### ## ###
####### ### ######## ### Volume 1, Number 1
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Published by the Center for Teaching and Technology, Academic Computer
Center, Georgetown University, Washington, D.C.
This paper is archived as COLLINS.IPCTV1N1 on LISTSERV@GUVM
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COMPUTER NETWORKS AND NETWORKING: A PRIMER
mauri p. collins, Pennsylvania State University
-------------------------
"It would be nice," I thought, "If I could just understand
what they are saying!" The earnest young person at our academic
computer services helpdesk had, from the tone of her voice,
answered my question. And I heard all the words, but it sounded
almost like a foreign language. I had recently bought a modem
for my home computer and had been told that a whole new world
would be opening up to me--but it was turning out to be a world
with a baffling language that didn't make very much sense to me.
I was asking the consultant what I thought was a relatively
simple question. I needed just enough information to get my
computer at home connected to my account on the university's
mainframe computer. And that was all I needed to know right
then. I was looking for an answer in terms of "Put this disk in
your drive, (or load this program on your hard-drive) and type
this..." But they insisted on explaining to me far more than I
could possibly understand. I was bewildered by the complexity of
their information and quite lost in their language. They seemed
to be assuming that, because I was asking the question, I could
understand their answer.
And I wondered how many of our readers had the same problems
with the technical terminology, and the acronyms that it seems
almost impossible to avoid. I have progressed in my under-
standing since I started and thought to share, in simple terms,
some of the basics I have learned about networks and networking.
A MODEM
A modem is piece of equipment that turns characters into
sound and back again, so that I can send messages that I have
typed, or am typing, out over a phone line to communicate with
other computers and other computer users. My modem processes
information at 2400 bits per second. (A "bit' (binary digit) is
the smallest piece of information that can be processed and is
actually an on or off electrical pulse. It takes a series of
these bits to represent a single character.) This is fast enough
for my needs, although the computer I use at work has a hard-
wired connection (a direct line from the back of my computer to
the mainframe computer) that transmits information back and forth
at 9600 baud (four times faster than at home).
NETWORKS AND NETWORKING
Of all the terms a new user of computer-mediated
communication has to deal with, "network" may be one of the most
confusing. One use of the word refers to the permanent, physical
connections between and among computers: the wires, fiber optic
cables, microwave links, phone lines etc. that connect computers
together, and allow their users to communicate with one another.
Another, more general use of the word refers to all those
computers, while not physically linked together, that circulate
messages with a particular set of headers (like Usenet NetNews
articles). This kind of network can be referred to as a "virtual
network". This means that the computers carrying the messages
may not be permanently linked together in a network that
physically exists, but are made by software to appear so (like
"virtual" reality and "virtual" memory). It is in this sense
that many people use the word "network".
The permanently connected networks comes in all sizes from
local area networks (LANs) of 2 or 3 machines linked together in
a single room to international, composite wide-area networks
(WANs) that span the globe and include satellites and microwave
transmission to move the information. The physical set up of
networks can be likened to a variegated patchwork of independent
telephone companies serving their own areas and yet linked
together so that they can exchange the virtual equivalent of
long-distance phone calls between distant locations.
THE INTERNET
The very first wide-area computer network in the United
States was known as the ARPANET and linked research universities
and military installations together so researchers could
communicate with one another and expensive resources (like
computers and databases) could be shared. Over the years this
initial network was joined by an ever increasing number of
regional and local networks. The Internet is made up of over
10,000 of these individual networks connecting over 20 million
users worldwide.
TCP/IP
With as many different kinds of computers and operating
systems and software that are in use, it has taken a great deal
of cooperation to come up with a common language and set of
standards that could be used to exchange information. One of the
most commonly used standards is TCP/IP (Transmission Control
Protocol/Internet Protocol). "Protocols" are specific sets of
instructions followed by computers for the transmission of data
among them. THE TCP/IP protocols also provide several useful
services to users, including FTP and TELNET.
Physical networks of permanently connected computers like
BITnet (Because It's Time Network), which use another set of
protocols, are connected to the Internet by "gateways" (computers
that translate alternative protocol languages into something
TCP/IP can understand, and they do it in a way that is
transparent to the user).
TRANSMISSION LINES - T3
The backbone of the Internet network in the United States is
made up of what AT&T calls their "T3" communications lines.
These are high speed data transmission lines permanently
connecting the major routing computers in the network. These T3
lines can be considered as the super highways of data
transmission. They have recently been upgraded from T1s which
carried 1.544 megabits (million bits of information) a second to
the T3s, carrying 44.736 megabits a second. This has
significantly increased the available "bandwidth", which
translates to the number and complexity of messages that can be
carried simultaneously. Initially all messages transmitted were
just text: characters and words. Now data sent over these lines
encodes everything from plain text to interactive, two-way
audio/visual teleconferencing.
IP NUMBERS
Each computer, large or small, which can connect to any of
the national networks has its own address or IP (Internet
Protocol) number. Each site with a national network connection is
given a specific range of numbers that it can use for its
internal machine addresses. The numbers are in the format of
123.456.789.123 with the last one or two sets of numbers
pointing to a specific machine, perhaps on a faculty person's
desk, or in a public computer lab. This is done so that mail and
other traffic can be routed correctly, and machines can be
identified when their user logs into other computers. We rarely
use the IP numbers in addressing mail or anything else, usually
preferring to use machine names in our addresses. I use a SUN
SparcStation with the friendly name of Wilbur, but who is known
to the network as 128.118.058.011. "Nameservers" are computers
that hold the lists that match the IP numbers to computer names
and locations and make these translations transparent to the
user.
MOVING TRAFFIC
When messages and files are passed through permanently
connected networks of computers like BITnet, the message "hops"
from one computer to another which "store and forward" messages
in a linear fashion, rather like a bus that stops at every bus
stop on its route. If a machine is temporarily off-line (broken
in some way, or being fixed or upgraded) then the messages just
sit patiently until the way is open again. Despite the fact that
electronic communication can move at the speed of light, I have
sometimes had messages take 16 hours to get from Virginia to
Nevada, and 4 hours from Washington, DC to Pennsylvania, and yet
at other times transmission appears to be instantaneous.
Some sites have Internet connections, some have BITnet
connections, some have both and some have neither. But there are
an increasing number of "gateways" from one to another and to the
commercial service providers. Some sites have leased telephone
lines that tie them to the nearest major switching center. The
lines are always open and available for traffic and their cost is
usually shared by the connected institution and various
governmental organizations.
FIDONET
Some sites run software that dials the nearest switching
center during the early morning hours, collects all the files and
mail that are waiting and delivers all the mail that it had
collected during the day. That one phone call may be the only
connection with the outside, networked world. "Fido" is one
example of this kind of software. "Fidonet" is the collective
name for the over five thousand computers owned by amateur
computer hobbyists throughout the world that use the Fido
software. Each computer is again assigned its own specific
address so that messages can be routed to the correct place. The
existence of Fidonet is not dependent upon universities or
government funding. There are no permanent, fixed connections
between these computers; all traffic goes over ordinary phone
lines and the cost is usually paid out of the individual system
owner's pocket. It doesn't matter where you are in the world,
there is probably a Fidonet node within easy dialing distance.
Fidonet provides person-to-person electronic mail, file sharing,
and hosts a large number of discussion groups/conferences called
"Echomail".
A brief introduction to Fidonet can be found at
FTP: lilac.berkeley.edu
File: /help/cat/mail/net/fidonet
and read on to find out how to get that file!
FILE TRANSFER PROTOCOL AND ANONYMOUS FTP
As I mentioned above, the TCP/IP protocols provide users
with FTP (File Transfer Protocol). This service is most often
encountered in the phrase 'anonymous FTP'. Many sites world-
wide have set aside diskspace on their computers to archive
(store) files and computer software and by using 'anonymous FTP'
these files can be retrieved almost as easily as if they were on
a local machine. You don't have to have an account at an archive
site nor do you don't have to pay for them, but you do have to
have FTP capability from your site (check with your local
computer gurus to find out if you have). Computer usage at most
sites is heaviest during the daytime, so please be polite and FTP
your files in the evening, night or early morning hours.
There are lists of 'anonymous FTP sites' which give some
indication of the kinds of files they have stored. To retrieve
the file via anonymous FTP:
FTP: pilot.njin.net
File: pub/ftp-list/ftp.list
That is the kind of cryptic instructions that just did not
translate into anything I could use...let's take it slowly:
To retrieve such a list, at your system prompt type "FTP
pilot.njin.net". (Only don't type the "", they are just there to
make the things you have to type easier to see in this text.)
And case-sensitivity is important (unix machines need you to
type "ftp pilot.njin.net"). Another important reminder is that
file names are case sensitive. You have to ask for files by
exactly the same name as they have in the directory listing. If it
says "ftp.list" or "KERMIT.help" or "Kermit.HELP", that is what you
must type.
Once you are connected it will ask for your name. You type in
"anonymous" and you have to spell it out and spell it correctly!
The machine will then tell you that "Guest login ok, send e-mail
address as password". Here you type in your full e-mail address.
This is often difficult, because what you type for a password
does not show on the screen. If you get it wrong, the machine
will chide you, but usually lets you in anyway. And leaves you
sitting staring at:
Guest login ok, some restrictions apply
ftp>
The file you are looking for is called
pub/ftp-list/ftp.list. This means that the file is called
"ftp.list" and is in a directory called "ftp-list" which is in a
directory called "pub". If you type "ls" at the first ftp>
prompt you will see a list of names. The top one is "pub", the
directory you are looking for. Typing "cd pub" at the ftp> will
get you into the public directory (it tells you that you have
changed directories) and leave you staring at another ftp>.
Typing "ls" again will give you another list of names, with "ftp-
list" about halfway down. Type "cd ftp-list" to get into that
directory, and to another ftp>. You can type "ls" again and a
list of filenames about fills your screen. About the middle of
the screen is a file called "ftp.list'.
To bring a copy of the file home, type "get ftp.list" and
the archive machine will send a copy of the file to your machine.
You can, of course, type "cd pub/ftp-list/" at the first ftp> to
go right to that directory, but it is often interesting and
productive to browse on your way to the file you are looking for.
And if you type "dir" instead of "ls" you will get a directory
listing that shows you how big the files are, and when they were
last updated. To get back to your own machine again, when the
archive machine tells you it has successful deliver your copy to
you, type "bye" at the ftp>. That usually works, but sometimes it
needs to be "quit" or "exit". Just try until you hit the right
one.
Different kinds of files are stored in different kinds of
formats. Text files are often stored in ascii (American Standard
Code for Information Interchange) and require no special
instructions to the machine before you ask that it be sent to
you. Some text files have special formatting so they can be
printed from a laser printer. They are perhaps labeled something
like ".ps" indicating they are Postscript files. Those
you would want to get just exactly as they are (as you would a
computer program, too) so you have to do one more step before you
ask the machine for the file. Because you want the file exactly
the way it is stored with no changes at all, you need to type
"bin" or "binary" at the ftp>, before you say "get ".
If there is any question about what kind of file you are dealing
with, use binary transfer (the file comes in machine language -
the equivalent of ones and zeros - makes no sense to you, but the
computers can understand them perfectly).
In order to save space on archive sites, files are often
compressed in a number of different ways. The programs needed to
uncompress them are usually stored at the same site, or your
local computer guru could help you. If files have any of the
following after their names, it is a clue they have been
compressed: .tar; .tar.Z; .tar.uu; .hqx; .sit; .zip; .arc; .Z.
Use binary transfer for these kinds of files.
A brief description of FTP is available from:
FTP: nic.sura.net
File: /pub/nic/network.service.guides/how.to.FTP.guide
If your site does not have an internet connection,
BitFTP is a mail interface that allows BITnet/NetNorth/EARN users
to FTP files from sites on the Internet. Most of the Internet FTP
commands can be used with BitFTP except the commands are sent in
a mail message, instead of interactively. This service tends to
be slow and your requested files may take hours or days to reach
you, so be patient. To get a brief guide to BitFTP, send a
message in the following form:
To: BITFTP@PUCC (or BITFTP@PUCC.Princeton.edu)
-------------------------------
HELP
This service is also available at no charge from Digital
Electronics Corporation's western regional mainframes. You can
receive information by sending a message in the following form:
To: FTPmail@decwrl.dec.com
--------------
help
TELNET
TELNET is another basic TCP/IP service that allows an
interactive connection with another machine. TELNET is both a
protocol (TCP/IP remote login protocol) and a program. TELNET is
used for two major purposes: to remotely login to a machine that
you have access to (i.e. a userid and a password) so you can use
it as if you were actually at that site; and to remotely login to
public access catalogues and databases.
I use TELNET to log into my accounts in Nevada and
Washington, D.C. from my computer account here at Penn State.
When I am travelling (with laptop computer in hand), I usually
arrange for login access at a local system so I can then TELNET
back to my home machine and keep up with my mail. How? You find
the e-mail address of a university or college nearest to where
you are going to be and send an email message to postmaster@. You ask, very politely, for a guest account that you
can use temporarily. Sometimes you get one, sometimes you are
given the access information to get to a point in their system so
you can TELNET out, sometimes you are invited to come to their
public computer labs and sometimes they just say "No". It all
depends on the administrative rules of the particular system.
Getting a guest account may be a mixed blessing, because the kind
of computer in use at the site may not be the one you are used
to.
When I am working online, I no longer reach over to the
shelf for my venerable and battered dictionary. I TELNET to
hangout.rutgers.edu, and following their menus through Library
and Reference and Dictionary, find the Short Oxford Dictionary
(8th edition, 1991) that they have made available online there.
Check them out, they have a lot of useful reference materials,
and a helpful set of easy to use
menus. A tip: when you have finished looking up your words hit the
return once at the "Word(? for help):" prompt. That will take you back to a menu
screen. From there typing "quit" gets you back to the main menu, and
typing "quit" again returns you to your own system.
Some of the remote sites you can telnet to, like library
catalogs and computers holding public access databases, need a
login name but it is usually published with information about the
service. These login names are case-sensitive, so type they
exactly as they are listed. There are two documents listed at
the end of this article that give the electronic addresses from
which you can retrieve lists of libraries, worldwide, who have
made their catalogs available for searching online.
A brief description of TELNET is available from:
FTP: nic.sura.net
File: /pub/nic/network.service.guides/how.to.TELNET.guide
ELECTRONIC MAIL
And as soon as I had my modem set up, I immediately used it
to become an emailer i.e. to send and receive electronic mail
(email). In my own case, I used my modem to reach my account on
one of Penn State's computers. However, I could have just as
easily (but for a fee) used my modem to dial the local access
number for any one of a number of commercial computer
communication service providers, like CompuServe, America Online
or Prodigy. Electronic mail is referred to as "asynchronous"
messaging because both parties do not have to be in contact at
the same time in order to communicate.
The first thing you have to know when you want to send email
to someone is their address, and always the easiest way to
determine that is to ask the person you want to send mail to.
Electronic mail addresses look very different from ordinary post
office addresses (called "snail mail" by email users). How an
address looks depends on what network the computer that their
account is on is connected to. I have accounts on machines that
access two different networks, the Internet and BITnet.
To send mail to my home address you need to know:
my name mauri collins
my house number and street Calder Square, P.O. Box 10002
my city State College
my state and zip PA 16805-0002
To send electronic mail to my Internet address you need to
know:
a login name (or userid) mmc7 fay
a machine @psuvm @archsci.arch
a location .psu .su
a domain .edu .edu
a country code (outside US) .au
ie: mmc7@psuvm.psu.edu or fay@archsci.arch.su.edu.au (Fay is in
the architecture department at the University of Sydney,
Australia)
Remember the periods or `dots' between the different parts
of the address (it reads out loud as "mmc7 at psuvm dot psu dot
edu"). Computers are confused by blank spaces in email addresses
so you will see the underscore or hyphen sometimes used as a
spacer as in mauri_collins@machine.location.domain.
Some addresses from other networks require an exclamation
point (!, called a "bang") between the parts of the address as in
psu!psuvm!mmc7 You just have to remember to copy addresses
carefully, or use the `reply' feature on the mail program on your
computer. It can generally be relied upon to take the correct
information from the "header" on the mail you have received, but
it is always an excellent idea to check.
Different Internet address domains you may see are .com for
business or industry, .mil for military address, .gov for
governmental addresses, .org for non-profit organizations, and
.edu for educational organizations. Addresses outside of the
United States often require a country designation. While Internet
email addresses generally go from the most specific to the most
general, mail going to the United Kingdom, and onto their Jnet
network needs to have the address turned around. If I were in
the United Kingdom my address might look like
mauri@UK.edu.psu.wilbur
On BITnet, each computer has its own distinct name, which
may or not be the same as its Internet name. My BITnet address
is now MMC7@PSUVM. However, when I was at another site, my
Internet address was collins@helios.nevada.edu or just
collins@nevada.edu, but my BITnet address was COLLINS@NEVADA3.
When sending mail from a computer that does not have a direct
connection to BITnet, it is usually necessary to add additional
routing information to the address as in: COLLINS@NEVADA3.BITNET.
DISCUSSION GROUPS
One of the more popular uses of networks, after the exchange
of electronic mail between individuals, is to join and read the
incredible variety of discussion lists or groups and news groups
that are available. Discussion groups come in many forms. Some
are like the bulletin boards in the local grocery stores.
Messages are posted and left for people to read and comment on;
some groups focus around particular topics, others are strictly
for announcements; while others read like the transcript of a
cocktail party.
Discussion groups have been likened to newspapers or talk
radio Many people read or listen or, to use the networker's term
"lurk", and a relatively small number of people contribute.
However, readership in a discussion group can bring people
together from all over the world, who might never have a chance
to meet and talk; it fosters the exchange of ideas and
information, and engenders a sense of co-operation and
friendship.
LISTSERV
Many of these discussion groups are handled by a program
called LISTSERV, written by Eric Thomas, that runs on IBM
mainframe computers. The groups are often called discussion
lists, because essentially what the LISTSERV software deals with
is a subscription list of electronic mail addresses. When a
message is received LISTSERV, depending on the instructions it
has been given, will forward it to the moderator/listowner, or,
if the list is unmoderated, copies the incoming message to each
of the addresses on its subscription list.
If the list is moderated then the moderator will check the
message against whatever formal or informal criteria exist that
govern what goes to the list's readership and either send the
message on, edit it, or return it to the sender. Most
moderator's see their primary role as `controlling the signal-
to-noise ratio'. This involves making sure that the discussion
is kept with the limits set forth in the group's charter, and
that discussion is conducted in a civil manner.
To join a discussion group, send mail to the LISTSERV at the
address given for the discussion group (e.g. LISTSERV@...) with a
single line in the body of the message, e.g.
TO:LISTSERV@guvm
------------------
SUBSCRIBE IPCT-L YOURFIRSTNAME YOURLASTNAME
You need to substitute your own name as in: subscribe ipct-l
mauri collins
A complete listing of the over 4000 LISTSERV groups can be
obtained using anonymous FTP from
FTP: FTP.nisc.sri.com
File: /netinfo/interest-groups.
Beware before you get it, the file is HUGE (over a megabyte).
A list of discussion groups in the humanities (over 800 of
them) is maintained by Diane Kovacs. The full list is available
as are grouped subsets of the whole list. Information on the
available files is available by anonymous FTP from
FTP: ksuvxa.kent.edu
File: library/acadlist.readme.
One unfortunate and often unpleasant aspect of discussion
and NetNews groups is the occurrence of "flaming". With no
available indication of tone or mood (except for the ubiquitous
smilies :-) (tip head to left shoulder to see the grin) it is
very easy for misunderstandings to arise and to escalate with
alarming rapidity. Free from the sanction of others' immediate
presence (and the fear of a pop on the nose for running off at
the mouth), there are those who tend to run off at the finger
tips and whose language becomes hostile, vulgar and profane. And
then there are those who chose to communicate in that tone all
the time. If a reasoned attempt to clear up the misunderstanding
is unsuccessful, a gracious exit from the communication situation
is often the best remedy, as censure or argument often seems to
exacerbate the problem.
USENET/NetNews
Usenet can be defined as computers that exchange messages
with Usenet headers. It is no longer refers to the physical
network of UNIX-using computers that it started as. Much of the
Usenet traffic is carried over the same computers that also
handle BITnet and/or Internet traffic. There are currently over
2000 different usenet newsgroups. The usenet groups are divided
into a number of major streams e.g. alt (alternative) comp
(computer) soc (social) rec (recreation) etc. There is no
central authority for usenet groups, although protocols have
grown up that govern the creation of new groups. No matter what
your interest you can probably find a Usenet group that discusses
it; if not, you can gather some like-minded correspondents and
start one. Some newsgroups are of local interest, like psu.jobs
that advertises employment available on Penn States' campus to
soc.women which is carried world-wide.
A complete list of NetNews groups is available via anonymous
FTP from:
FTP: rtfm.mit.edu
Files: List_of_Active_Newsgroups,_Part_I
List_of_Active_Newsgroups,_Part_II
Alternative_Newsgroup_Hierarchies,_Part_I
Alternative_Newsgroup_Hierarchies,_Part_II
DIFFERENCES BETWEEN LISTSERV AND NetNews
There are some significant differences between Usenet
NetNews and the LISTSERV discussion groups residing on BITnet and
the Internet, most of which show up from the computer user's
perspective. A user subscribes as an individual to LISTSERV and
similar discussion groups and the messages that LISTSERV forwards
are received in their personal mailbox.
In order to read the NetNews newsgroups one's site has to
receive some part of the "feed", the stream of NetNews messages
which can be measured in tens of megabytes each day. This is
stored at a central location on the site's mainframe and accessed
by some kind of reader software. Sometimes NetNews messages are
available on campus through the same system that handles on-
campus discussion groups. Messages are held for whatever period
of time the site administrators decide is appropriate and this is
often dictated the amount of storage space available. A site may
receive some, all or none of the newsgroups.
The first word in the name of the newsgroup is kind of a
`family' name, to indicate which of the main divisions the group
belongs to: comp.misc is a computer-related group, soc.women is
from the social science grouping, rec. deals with recreational
topics, talk. indicates discussion groups, bit.LISTSERV indicates
groups that are mirrors of BITnet/Internet LISTSERV groups.
GUIDES TO MORE INFORMATION
Always the very first source of information on anything that
pertains to access to the computers at your site, how they are
set up, what programs are installed and how to run them, is your
very own site computer gurus. They are most knowledgeable about
the idiosyncracies of their equipment and programs and can
provide you with instruction, written guides, access to training
classes etc. Often your own site will have an FTP server set up,
or a public directory from which information, files, and programs
can be downloaded (copied from the mainframe to your personal
computer).
There are a host of extraordinarily good guides to the use
of computer mediated communication, and lists of such guides. One
comprehensive beginner's guide is the work of John December at
Rensselaer Polytechnic Institute and is available via anonymous
FTP from
FTP: ftp.rpi.edu
File: pub/communications/internet-cmc.
Another is Scott Yanoff's "Internet Sources Guide", This is
updated bi-weekly and is posted to the NetNews group
alt.internet.services, or is available by anonymous FTP from
FTP: csd44.csd.uwm.edu
File: pub/internet.services.txt.
I have been thoroughly enjoying my wanderings around in the
networks, and have found a wealth of knowledge and a host of
friends. But I will warn you--it can become a time-sink--with
all your spare moments disappearing off into cyberspace.
Biographical note: ms collins is pursuing a Ph.D in Instructional
Systems at Penn State, after having earned both BA and MA in
Sociology at the University of Nevada, Las Vegas. She is
currently a research assistant in the Center for the Study of
Higher Education working on a national study of the use of
instructional technologies in higher education, funded by
the Corporation for Public Broadcasting.
------------------------------------------------------
Interpersonal Computing and Technology: A Journal for the 21st Century
Copyright 1993 USA.
All articles in this publication may be cited
under the fair use provision, provided proper bibliographic
information is used including name of author, title of article,
date and journal identification. Authors retain the copyright
for all articles in this publication. Any commercial use of this
journal in whole or in part by any means is strictly prohibited
without written permission from the author(s) and IPCT-J.
Contributions to IPCT-J, can be submitted by electronic mail in
APA style to: Gerald Phillips, Editor IPCT-J GMP3@PSUVM.PSU.EDU
Brought to you by emoderators.com
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Berge
Collins Associates
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September 9, 2006
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