On-Line #08 29 октября 1995

Интернет

E-MAIL - E-Mail What is it?

                 E-MAIL



   It has been almost a month since, when I started working my
BBS (Alex). Since network C-DOS on the ZX-Spectrum, we still 
young, many can not imagine: what is it all about? 


   With almost twelve years of experience in the IBM PC and two 
years "Seniority" of the international network of FIDO 
(1994-1995), I suddenly decided to open a BBS on my favorite - 
Speccy (thanks to the developers C-DOS modem and respected KSA, 
ROBERTu for further development this idea), to give you all 
those amenities which provides e-mail. 


   Analyzing with your files on the server I was the first (!) 
Collided with the chaos. It should be noted that my regular 
users (and there are 11 men) carefully read exposed me the 
information and have long switched to a single international 
standard targeting correspondence (see below). But with the 
expansion range of users increasingly began to appear and junk 
files, anonymous matershina ... And I decided a little show 
you: How does it Looks at IBM:



              E-MAIL - WHAT IT IS



   Now becoming increasingly popular e-mail system.
What is it, how it can be used as a sort of address E-mail? 
About all this - this article. 


   What is the mail - we know. These are the traditional means 
of communication, to exchange information, at least two 
subscribers. In order for this exchange took place, you must 
write the message, and specifying the address, delete the 
mailbox from letter will inevitably fall to the mail site. If 
the specified address conforms to generally accepted standards, 
then after a while the postman put it in the mailbox recipient. 
Further, the subscriber will open the message and - the 
exchange of information took place. To expedite the process, 
you pick up the phone, dial the phone number and, if there is a 
correct connection, then your caller will hear what you want to 
refer to it. If the subscriber does not answers or the line is 
busy, it is necessary to repeat the procedure more again, 
regretting that you spend on this precious time. 


   These two types of communication - mail and telephone - have 
become for us traditional, and we are already well aware of 
their strengths and weaknesses. And what is email? 


          What is an e-mail



   When the ARPANET was first entered into the arena, its 
developers expected to be the predominant traffic (ie ect the 
amount of information transmitted between the nodes) of the 
"process-process." They mistaken. To their great surprise, the 
volume of email between people blocked the volume of 
communication between processes. At that time, as snow, rain, 
heat could not stop mail carriers, the possibility of the 
ARPANET to deliver messages from the west coast to the eastern 
U.S. The compound for a few seconds to start revolutionary 
processes in the media Ups. 


   The main attraction of the email - its speed.
However, there are other advantages that are not so widely 
known. The phone also provides almost instant access, but 
studies have shown that about 75% of telephone calls come to an 
end vain ("I'm very sorry, but Mr. Smith at the meeting / left

on a business trip / out of the room. "). E-mail has the
the same access speed as the telephone, but does not require 
the simultaneous presence of both subscribers at different ends 
of the telephone line. In addition, it leaves a written copy of 
the message which can be saved or forwarded. Moreover, the 
letter can be simultaneously sent to multiple parties.



   Suppose that you were lucky, and you become the proud owner 
of a PC. You were a message to his subscriber - have entered 
into a computer text, prepared to transfer the file containing 
any program or, for example, graphical data, specify the 
address and took off up the phone, handed over a phone line 
your letter. His phone is busy? It's not scary: how only the 
line becomes free, he will be able to get your message. Pick up 
the phone and dial the phone number will not you, but rather 
intelligent electronic device called a modem. In the simplest 
case, the transfer of your letter to happen Next Arrow way: 
First you have to run from the standard procedure of your modem 
will try to connect to a modem installed on the mail machine 
(analog - post offices (BBS)). Once communication will be 
established, will identify your subscriber item (your 
computer), password verification and transfer of prepared for 
your information. After that, your modem will hang tube. "You 
can safely go about their business, and in this time postal 
machine will test whether the correct address you indicated, 
and if everything is ok, will try to contact your subscriber. 
Once the two modems - email and your caller - "Contract" will 
transfer your message. Exchange of information took place. 


   Convenience of such means of communication can not be 
overestimated. Speed, burdensome, to transmit information of any

volume anywhere in the world.


   While e-mail can be viewed as a special case of file 
transfer, it has several features which are not familiar 
standard procedures for file transfer. First, the sender and 
receiver are almost always men, not machines. This means that 
e-mail system consists of two distinct but closely related 
parts: one interacts with person (eg, drafting, editing, reading

messages), another - the transfer of messages (for example, 
spamming lists, ensuring the transfer).



   Another difference between e-mail and Internet file transfer 
utility lies in the fact that e-mail messages constitute a 
clearly structured document. In many systems, each message is 
accompanied by a large number of additional fields. They 
include the name and address of the sender's name and address 
of the recipient, the date and time of sending the letter, a 
list of people who have sent a copy of the letter, the level of 
significance, degree of secrecy and more.



         Addressing in the e-mail



   To ensure that your email reached its destination, it is 
necessary that it be designed in accordance with international 
standards and has been standardized by the postal mail address. 
A common format for messages is determined by the document 
entitled "Standard for the Format of ARPA - Internet Text 
messages ", for short - Request for Comment or RFC822, and has 
a header and a message directly. Title is approximately as 
follows: 

From: e-mail e-mail - from whom came the message
To: zip email address - who the
Cc: mail e-mail addresses - who has directed
Subject: message subject (of arbitrary shape)
Date: Date and time of sending messages


   Header line From: and Date: are formed, as a rule, 
automatically, programmatically. Aside from these header lines, 
the message may contain other, for example: 


   Message-Id: a unique identifier for the message assigned to
his postal vehicle

   Reply-To: usually the address of the person you are 
responding to sent you a letter



   Message itself - usually a text file rather arbitrary shape.


   Zip e-mail address can have different formats. The most 
widespread system of formation of DNS addresses (Domain Name 
System), used on the Internet. Decryption address and translate 
it into the required format shall embedded software used in the 
electronic network mail.



   From the standpoint of logic, in order to address was 
informative, it is necessary that there were: 

   - ID of the subscriber (by analogy - a string TO: to mail 
the envelope); 

   - Post the coordinates that define its location (on
analogy - a house, street, city, country on the mail envelope).


   Postal E-mail has all these components. For
In order to separate the caller ID on his e-mail
coordinates @ icon is used. Zip email address
Internet format might look like:

               aspet@htd.mepi.msk.ru


   In this example, aspet - ID subscriber
, as a rule, from the initial letters of his surname,
patronymic (Anatoly Petrov). What is the right of the
@ sign, called the domain and clearly describes the location of 
the caller. Components of the domain are separated by dots. 
Most the right to designate the recipient's country code - this 
is the top level domain. The country code is approved by 
international standard ISO. In our case, ru - code of Russia.



   The next subdomain - msk in our case - is uniquely defined 
within the top level domain. It is not hard to guess what it 
stands for code of the city - Moscow. The collection of 
components domain msk.ru called second-level domain. 


   Third-level Domain - mepi.msk.ru. In our case, domain
third level includes the abbreviation of the English 
abbreviation of the Moscow Engineering Physics Institute. 
Regulation of Education names in third-level domains - a 
private matter of second level domains. 


   Subdomain htd - registered at the mail host name of the 
machine which owns the mailbox above Anatoli S. Petrov.



   The DNS is only to show that
nothing complicated and unusual, even for novice caller
e-mail about this.


                Teleconference



   Further development of e-mail - e-newspaper,
Subscribers who are both its correspondents.
This is the so-called news (news) or teleconferences
- Large groups of people communicating via computer networks. 
The most popular teleconference conducted by the network 
USENET. USENET contains groups (sections) of news, broken by 
subjects. Each subscriber has an opportunity to appeal to a 
certain section of it and get all the news coming back or send 
your information. The main groups are: Computer Science (comp, 
short for computer), science (sci - Science), social (soc - 
social), miscellaneous (misc - miscellaneous), recreational 
(rec - recreation), etc. 


   Sections appear and disappear depending on the interest
shown by subscribers.


   Our network is a distant analog conferencing is a daily 
ON-LINE. 

                 E-mail to Russia



   The whole world has long enjoyed the postal services of such 
well-known computer networks as EUnet, BITNET, MCI Mail, 
CompuServe, CSNET, Internet, and free user network FidoNet.



   In Russia, you can Become a subscriber network messaging
RELCOM, which is part of the Internet and having an 
international status. Relcom given an opportunity to share 
information with any subscriber in Russia and abroad. True, it 
should be noted that a paid network. 


   Perhaps, given that users will be educated and in his 
correspondence standard mail targeting international computer 
networks, some SYSOP, with two computer, connect to our nascent 
Moscow network C-DOS to non-profit user network FidoNet!? It is 
not hard done with two computers with modems, but until this 
can be only dream of ...



   This text was on my BBS under the name e_mail.W. To me he 
was two years ago from the network FidoNet. With a few 
additions I and offer it to you to adopt a single international

Standard and stop roughhouse on BBS.

                       BBS 164-1684; 22.45-07.15
                       Aleksey@alex.msk.ru
                       On: SCHEDULE (in BBS)

Materials:
A. Tanenbaum. "Computer Networks" (Second Edition),
Prentice-Hall International, Inc., 1989.

D. Frey, R. Adams "A Directory of Electronic Mail Addressing and
Networks. "O'Reilly 'Associates, Inc., 1990.

J. Quarterman. "The Matrix. Computer Networks and Conferencing
Systems Worldwide. "Digital Press, 1990.

D. Comer. "Internetworking With TCP / IP." (Second Edition).
Prentice-Hall International, Inc., 1991.

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