ARM Club 1/ARM_CLUB_CD.iso/contents/apps/comms/a/internet/Internet

Text File | 1993-10-18 | 39.7 KB | 716 lines

***************************************************************************
                          EXPLORING THE INTERNET
***************************************************************************

Paul L. Allen roams the Internet from the comfort of his living room and
shows how, with the aid of Demon Internet Services and a modem, you can do
the same.
---------------------------------------------------------------------------

INTRODUCTION

The Internet is the world's largest computer network.  Nobody knows quite
how large, but one estimate puts it at around 1.7 million computers in over
125 countries, with an average traffic increase of 20% per month.
Most of the machines on the net belong to large academic institutions and
multi-nationals with many thousands of users.  A smaller number belong to
companies and organisations with hundreds of users.  An even smaller
number, but one that is growing fast, belong to individuals who pay a
service-provider for dial-up Internet access.

With the exception of dial-up 'leaf' nodes, Internet machines communicate
over dedicated, full-time, high-speed links, ranging from 64kb/s to over
1Mb/s for the 'backbones'.  Unlike Fidonet - a network of Bulletin Board
Systems (BBSs) - where participating machines phone each other in the small
hours to exchange mail, Internet mail is delivered to the other side of the
world almost instantly.  If you want a file from a machine in the US you
don't have to dial direct, or make a file request which may take days to be
delivered - just use the file transfer protocol (ftp) to download it over
the net.  The Internet protocols are such that you can be sending and
receiving e-mail (electronic mail), downloading Usenet news (the equivalent
of BBS public message areas), downloading a file and chatting to someone
halfway across the world all at the same time.

There are several companies in the UK which provide varying levels of
Internet connectivity, ranging from mail-only (sometimes with restrictions
on monthly traffic levels), to a full-function feed.  Many companies which
do not offer a full-function service are restricted to a two-stage form of
file transfer: first from the remote site to the provider's machine, then a
download from the provider's machine to your machine (most providers with
this sort of service add insult to injury with high connect-time charges).
Of those offering a full-function Internet connection, the cheapest is
Demon Internet Services (DIS) who charge £10 per month with no connect-time
charges, no traffic charges and no limit on connect time (there is an
initial setup charge of £12.50, both prices are exclusive of VAT).


ORIGINS

The Internet was born about 20 years ago from research by the US Defence
department's Advanced Research Projects Agency - they were tasked with
designing a network which could withstand partial disruption (resulting
from enemy action) and still function.  The design they settled on was a
packet-switching network - data is parcelled into Internet Protocol (IP)
'packets' which are labelled with the address of the destination machine,
the packets are then passed from machine to machine until they reach their
destination.  Routing tables are used to determine which of a machine's
neighbours are the best way of reaching the destination, but in the event
of a failure in the link an alternative route will be used. Route-switchover
can occur between one packet and the next, so packets have sequence numbers
allowing them to be reassembled correctly even if they arrive out of order
(as may happen if a packet goes astray and the receiver requests it to be
retransmitted).  Because IP packets have a maximum size, it is the task of
the Transmission Control Protocol (TCP) to split data into convenient-sized
chunks to be sent out by IP, hence the whole mechanism is usually referred
to as 'TCP/IP'.

In the late 1980s the US National Science Foundation created five
supercomputer centres to be shared by academic sites across the country.
Although bureaucratic problems prevented the NSF using ARPAnet directly,
they could and did adopt the same technology to provide their own NSFnet.
A packet-switching system with sites linked to their geographic neighbours
proved much cheaper to implement than linking each site separately to a
'hub' supercomputer centre.

The ARPAnet evolved into two military networks, one for classified
information and one for unclassified information, the latter eventually
merging with NSFnet, NASA's Science Internet and others to form what is now
known as the Internet - a network of networks all using the TCP/IP
protocols.  The Internet also has gateways into many other networks such as
Fidonet, BitNet, and JANet (the UK Joint Academic Network).  The gateways
are seldom full-function and often limited to exchanging mail and news,
although JANet is in the throes of changing from its own proprietary
protocols to TCP/IP and many UK academic sites are now 'on the Internet.'
Because the Internet is an amalgamation of several networks, nobody is in
overall charge, rules (such as whether commercial traffic is permissible)
vary from subnet to subnet, funding of subnets comes from a variety of
sources and the whole thing is essentially a cooperative anarchy.

The workings of the Internet are controlled by a voluntary membership
organisation called the 'Internet Society' who invite volunteers to
the 'Internet Activities Board' (IAB) to promulgate standards and
allocate resources.  The IAB has two subsidiary task bodies, the
'Internet Engineering Task Force' (IETF) and the 'Internet Research
Task Force' (IRTF).  Users express their opinions to the open-membership
IETF, whilst the IRTF is concerned with the development of new
technologies.  These various organisations produce documents called
'Request For Comments' (RFC) which are eventually either adopted by
concensus or die a quiet death.  Even so, it takes time for the proposals
in an RFC to be incorporated in every package on every machine on the net,
so those which amend or extend existing services are written in a way that
some degree of inter-operability is maintained.

But enough of the theory, on to the practicalities of accessing the
Internet via DIS...


NAME AND ADDRESS

A full-function feed, such as that offered by DIS, means that your machine
becomes a site on the Internet just like any other (except that it's not
continuously connected), with its own name and address.  Addresses apply to
network interfaces, and something called a Domain Name Server (DNS) maps
names to addresses in a complex manner - one address could be the target
for several different names, whilst a large system can nominate a central
machine for mail-handling (this is how DIS deal with their subscriber's
e-mail).  Normally names are used in preference to addresses because this
allows system administrators to transparently move functions between
different machines.  For instance, my site is called 'sktb.demon.co.uk'
and has the address '[158.152.9.18]'; you can e-mail me as
'[e-mail]'.

Because the Internet started as a US-only phenomonon, names originally took
no account of country, and site names were organised into 'edu' (education), 'com' (commercial), 'mil' (military), 'gov' (government), 'net' (network
providers) and 'org' (miscellaneous organisations), so you would see site
names like 'cs.indiana.edu' (Indiana University Computer Science dept.)
or 'whitehouse.gov' (guess). When the Internet crossed national boundaries,
top-level domains were allocated to each country ('uk' for the UK, 'de' for
Germany, etc.), and each country controlled how that namespace was used -
the UK uses 'ac.uk' for academic sites, 'co.uk' for commercial sites and
'mod.uk' for Ministry of Defence sites (there is currently a move to a
'gb' namespace in the UK, but this has met with opposition).  Although
the US has the top-level domain of 'us' it is rarely used. Multinational
companies with sites in many countries prefer the 'com' top-level domain
anyway as they frequently have dedicated lines between sites in various
countries.

DIS sites are all of the form 'entity.demon.co.uk', where 'entity' is
between 4 and 8 characters chosen by the user (it is wise to have a few
alternatives ready when you subscribe).  When using the DIS service it is
possible to omit the '.demon.co.uk' part when referring to another DIS site
(though it is probably wise not to do so with e-mail). Sites of interest
are 'gate' and 'hinge' (London dial-in sites), 'hel' (Warrington),
'clootie' (Edinburgh), 'post' (mail server), 'news' (news server) and
'irc' (Internet Relay Chat server).

There are no restrictions on the number of usernames your site may have
(either to segregate incoming e-mail or because several people use the
machine), but DIS insist that e-mail and news be read and composed on the
machine used to connect to their service.  It is an Internet requirement
that all sites have a user called 'postmaster' for dealing with complaints
and mis-addressed e-mail, (this is just a matter of checking the appropriate
mailbox occasionally) - DIS also use 'postmaster' when e-mailing important
announcements to their users.  For an additional annual payment of £200 DIS
allow you to pass mail and news over an internal network, and this also buys
an 'alias' name for your site such as 'xyzsoft.co.uk'.  Although in theory
BBSs must pay the supplement so their users can upload / download mail or
news, DIS generally waive this requirement if traffic is not excessive
(but ask first).

A number of Acorn-related companies are on the Internet, including Acorn,
Computer Concepts, Aleph One, Acorn User, Spacetech, and The Serial Port
(the last three use DIS).  A number of Archimedes BBSs have also subscribed
to DIS with the intention of transferring e-mail and news to their boards.


PING

Ping is used to find the round-trip time between your site and another.
This is useful for estimating if there is excessive loading either at
routing machines or at the remote site.  It is also an innocuous way of
checking that you actually have a working connection - if you were
connected to 'gate' then the command 'ping gate' should give a time
of around 250ms under light loading.


FINGER

The strangely-named finger allows you to find out who is using a remote
machine.  The command 'finger @site' will list all people logged on to a
Unix machine, whilst 'finger *@site' will list all people who have accounts
on that machine whether logged on or not (with single-user machines the
'@site' form usually gives the same results as the '*@site' form). Using
'finger username@site' will give more detailed information on that
particular username.

DIS have extended the way finger can be used with their machines so that
additional information is supplied.  The command 'finger yoursite@post'
will tell you how many mail messages you have waiting and who they are from, whilst 'finger any-other-demon-site@post' will tell you how many messages
are waiting for that site (but not who they are from).  As a service to
those machines whose software can't handle DNS, you can use
'finger any-site@gate' to get the numeric address of that site e.g.,
'finger archie.doc.ic.ac.uk@gate'.


E-MAIL

Electronic mail allows you to exchange private messages with people all
over the world.  They don't even have to be on the Internet as there are
mail gateways to many other networks such as JANet and Fidonet (delays
inherent in Fidonet may result in transit times of up to a week).  You may
send the same message to multiple-recipients, possibly marking some as 'Cc'
(this derives from the term 'carbon copy' used on memos) rather than as
direct recipients.  Some sites have difficulty with large e-mail - a safe
size is no more than 1000 lines of 80 characters (you should stick to
80 characters or less as many people read mail on simple terminals).

Incoming mail for a subscriber is delivered to DIS, who hold it until the
site logs on.  Actually, mail is only held for a month, though it is
possible to make special arrangements in exceptional circumstances.

It is important to realise that although JANet specifies site addresses
'the wrong way round' you should express them in normal Internet format.
As an example, mail from Simon Burrows may say it's from [e-mail]
but you should reply to [e-mail] or DIS will reject it.  JANet
know that the rest of the world drives on the right, and automatically
reverses Internet-format addresses (some problems arose when Czechoslovakia
joined the Internet with a 'cs' top-level domain - the Computer Science
depts of some UK academic sites had to switch from 'cs' to 'dcs' to avoid
ambiguity).


USENET NEWS

Also known informally as 'Netnews' (or just 'news'), this is the equivalent
of Bulletin Board public message areas, but with Usenet there are many
thousands of newsgroups with traffic in excess of 70Mbytes/day (DIS hold
local news for 14 days and other groups for 10 days).  Usenet is neither a
network or a type of software: it is a set of standards for the exchange of
news messages - most Internet sites exchange Usenet news, but so do sites
on many other networks.  Since there are conventions for 'wrapping' news in
an e-mail message, Usenet news can be transferred between networks via
e-mail gateways.

News articles are tagged with labels identifying which newsgroup or groups
they should appear in so that users can download only those topics which
are of interest.  Articles may appear in more than one group (cross-posting)
if they are of relevance to more than one subject area.  It is also possible
for an article's author to specify that follow-ups should appear in a
different group to the one in which the article itself appears (usually
because the current 'thread' of conversation has evolved to the point that
the original group is no longer appropriate).

The groups distributed worldwide are divided into seven broad
classifications: 'comp' (computing), 'sci' (science/theory),
'soc' (social issues), 'talk' (debate, often without useful conclusion),
'news' (news network / software / admin), 'rec' (recreation / art
/ hobbies) and 'misc' (stuff that doesn't fit the other categories, or
transcends categories).  These major hierarchies are (usually) circulated
around the entire Usenet - this implies world-wide distribution.  Not all
groups actually enjoy such wide distribution: some sites take only a
selected subset of the more 'technical' groups, and controversial 'noise'
groups are often not carried by many sites - it is entirely up to a site's
news administrator as to which groups are carried and which are not (lack
of disc space may be more of a deciding factor than a desire to censor;
DIS endeavour to obtain every group available).  Some groups are moderated
- articles posted to the group will automatically be diverted and sent as
mail to the moderator who must approve them before they can be exchanged
between sites.

As well as the major hierarchies there are many alternative hierarchies.
There are national ones such as 'uk' and 'scot', specialist ones
such as 'bionet' (biology) and 'vmsnet' (DEC's VMS operating
system) and the catch-all 'alt' (where people go when they can't
persuade the major hierarchies to create a particular group).  Finally
there is the 'demon' hierarchy for DIS subscribers.

New users should subscribe to 'news.announce.newusers' for the regular
articles on 'netiquette', and to the various demon support groups such as
'demon.announce', 'demon.ip.support' and  'demon.ip.support.archimedes'
(though I would recommend getting all  'demon' groups initially, then
'pruning' them down).  Of particular interest to Archimedes users are
'comp.sys.acorn', 'comp.sys.acorn.announce', 'comp.sys.acorn.tech' and
'comp.binaries.acorn'.  Test postings should be sent to 'demon.test'
where they won't annoy people.  It will take around ten minutes or so for
an uploaded article to appear on the news-server, so don't expect to see
your postings immediately.

To conserve net-bandwidth, news uses a 'flood-fill' algorithm.  Sites
wishing to exchange news first transfer a list of those news articles
(identified by their unique message-IDs) which have arrived since the two
sites last exchanged news.  Each site then requests from the other those
articles which it does not have (as previously noted, a site may choose not
to carry particular groups).  Because of this exchange mechanism, articles
may arrive out of order, and you can see a follow-up before the article
which prompted it.  To get around this problem people 'quote' bits of the
article they are responding to, usually by preceding the quoted lines with
a '>' (although other characters are also used).

For example:

"In article <[e-mail]> Paul Allen <[e-mail]>
writes:

> Why aren't Acorn more forthcoming with patches?

I second that - when will Acorn officially release the serial port
patch?"

The golden rule when quoting is 'trim to the absolute minimum' - nobody
wants to see a follow-up quoting an original article in full just to add
a brief comment on the first paragraph.

Abbreviations are very common in news postings, both to conserve bandwidth
and to save typing.  Common ones are AFAIK (as far as I know), BTW (by the
way), IMHO (in my humble / honest opinion), IMNSHO (not so humble),
ISTR (I seem to remember / recall), IYSWIM (if you see what I mean),
OTOH (on the other hand), RO[T]FL (rolling on [the] floor laughing), and
WRT (with respect to).  One abbreviation you may also encounter is RTFM,
which means 'Read The Flipping Manual' (or something like that) - if you
post a query to 'comp.sys.acorn.tech' asking how to format floppy discs
you may well see this amongst the answers...

Since news postings are often written in a hurry by people who may not be
masters of expression it has also become conventional to use 'smilies' to
denote mood, be it humorous or otherwise.  The prototypical smily is
':-)' which represents a smiling face (turn the page 90 degrees clockwise),
and is used to indicate humour.  Many other smilies exist: there is no
concensus on precise meaning, but here is a small selection...

:-) smile    :-( frown        :) smile     ;-) wink
:-D laugh    8-) wide-eyed    :-} smirk    :-| deadpan


Conventions used on other nets have also crept in, so you may see the odd
'<grin>' or even '<g>'.  Like exclamation marks, smilies should be
used sparingly.  Other conventions are used to get around the
limitations of ASCII text: emphasis is denoted by using *asterisks*
although _some people_ prefer to use underscores, whilst all upper-case
is considered to be the equivalent of SHOUTING and is usually frowned upon.

Also common are signature lines (sigs) at the end of postings, where the
poster typically gives contact information or adds a witty aphorism.  The
recommended maximum size is 3 lines, and it is a good idea not to exceed
this.

Most groups post a 'Frequently-asked Questions' list (FAQ) at least once a
month.  This gives answers to those questions which are asked by every
'newbie' to the group, and you are strongly advised to read the FAQ
before attempting to post to any newsgroup except the 'demon' ones (see
the next paragraph for why this is a good idea).  Waiting for the FAQ also
means you have time to get a feel for the general 'mood' of a group before
wading in.  It is also a good idea not to join in a discussion part-way
through - you may end up repeating things that have already been said many
times before.

Another thing you may encounter is a 'flame' where someone is publically
taken to task for posting rubbish, or a company is slated over some aspect
of its products.  If the attack is particularly vituperative or if other
portions of the article express approval, the attack may be highlighted as
follows:

"*FLAME ON*
You'd know the answer to this if you bothered to read the FAQ
instead of wasting our time asking silly questions.
*FLAME OFF*"

Presumably the convention arises from the Marvel comic-book character
called 'The Torch'.  Some things likely to attract flames are asking
silly questions, quoting private e-mail without the author's permission,
posting a test message to a non-test group, over-quoting, over-long sigs
and quoting somebody else's sig in a follow-up.

Group creation is a thorny issue, even in the alt hierarchy where anything
goes: my advice is to wait at least 6 months before even considering
attempting to get a new group created, think again, then put it off for
another 6 months (see previous paragraph for what can happen to those who
behave rashly).

The contents of certain newsgroups can be a sensitive issue - Usenet news
reflects everyday life and is often 'adult' in content.  Just as some
people find some types of behaviour unacceptable, they may also find the
contents of some groups unacceptable.  The answer for news is the same as
for real-life - avoid the bits that make you uncomfortable.  If you dislike
the unrestrained humour of Roy 'Chubby' Brown you'll want to give
'alt.tasteless.jokes' a miss.  If you were brought up to think that sex was
somehow dirty then you'll not want to read 'alt.sex' (and certainly not
'alt.sex.bondage'..  If you get embarassed when you walk into a pub and
find it's a 'gay' bar then you probably won't want to read
'alt.sex.homosexuality'.  If you object to the magazines traditionally
placed on newsagents' upper shelves you won't want to get
'alt.binaries.pictures.erotica'.  Unfortunately, no group is immune from
'adult' language - even the 'genteel' groups suffer the occasional
immoderate outburst in much the same way that a quiet afternoon in a park
can be spoilt by a gang of lager-louts running around swearing.  For these
reasons, parents may not wish their children to have unsupervised access,
and should take the appropriate steps.  Those who find the unfettered
liberty of Usenet disturbing should remember that the police no longer
consider written material to come under the terms of the Obscene
Publications Act, that 'erotic' pictures are usually scanned from magazines
available in newsagents, and that the connectivity of the Internet means
that banning UK sites from carrying these groups would not prevent people
in the UK reading them - the only way of preventing access to such groups
is to cut the UK off completely from the rest of the world.


FTP

Ftp stands for 'file transfer protocol', and is the primary mechanism by
which files are transferred over the Internet.  To transfer files from a
remote machine requires that you know a valid username and password for
that machine, and that the relevant files are open to access by that
username.  Although this is fine for transferring files around different
sites or machines belonging to a single organisation, it doesn't seem to
offer much scope for the rest of us.  However, many Internet sites found
that they were accumulating Public Domain files related to a particular
subject and decided to make them available to everyone - a move which was
not entirely altruistic because they could then pick up other files as
required from similar public-spirited sites (the Internet version of 'stone
soup').

Sites which make files available for public access generally use the
convention known as 'anonymous ftp'.  When ftp asks for a username, enter
'anonymous' (some sites also accept 'ftp' as the username but some
don't).  You will then be either asked for a password, in which case you
should enter your username and sitename in the same format as for e-mail
(e.g. '[e-mail]') or for your ident, in which case you
need only enter your username.  Although many sites don't check if you give
a false sitename, it is in your own interest to tell the truth as
administrators use this information to plan future upgrades (it's also good
manners).  By convention, most ftp servers place you in the 'pub'
directory, although some (like DIS) place you in the root directory.

There are many different operating systems on Internet machines, and they
all have their own ways of naming files and moving around directory
structures.  To simplify matters, most ftp servers understand a limited
subset of Unix-style commands (mainly because most of the machines on the
net run Unix), hybridised to a lesser or greater extent with conventions of
the underlying OS.  Many implementations will accept Unix-style commands
and filenames throughout, others require a knowledge of file-naming
conventions on a particular OS.  Different OS's use different end-of-line
markers in text files: in 'text' mode ftp will perform end-of-line
conversion, in 'binary' mode it won't - make sure you choose the right
mode for the job.  Since the Unix command to recursively list all files is
'ls-lR', Unix ftp sites usually have a file called 'ls-lR' (Unix
filenames are case-sensitive) which lists all the files available from that
site.

There are a number of sites offering files of interest to Archimedes users
(a list giving details appears once a fortnight on
'comp.sys.acorn.announce'), however most of the files eventually make
their  way onto BBSs and PD library discs.  You may find that you use ftp
more for non-Archimedes files: sources for PD multi-platform programs,
text files, weather images or the like.


TELNET

Telnet allows you to login to a remote machine as though you were actually
a local user.  Not many sites are happy to let just anyone login, but there
are a number of special services (on-line library catalogues, Internet-wide
file searches, etc.) offered by various sites which are accessed via
telnet.  DIS use telnet to allow subscribers to change their passwords:
'telnet gate' and follow the instructions.

Telnet sessions can be directed to specific numbered 'sockets' (the default
is 23) to perform other tasks.  For instance, telnet is the underlying
mechanism by which DIS implement their news-server 'telnet news 119'
will expose you to its hidden inner workings should you feel so inclined.

Because the operating systems of most home computers don't support multiple
users, telnetting to one will usually end up with a session in which what
you type is echoed on the other person's screen and vice-versa - so
you can chat to someone whilst you wait for an ftp~session to complete.
Things get a little confusing on DOS if someone telnets in for a chat, the
solution is to use socket 87 when chatting to DOS machines.

A number of information services (such as University library catalogues)
are databases which may be accessed by local users or remotely via telnet,
and are thus available to the internet community.  Most have a 'dumb
terminal' interface which can be telnetted directly, some also have
menu-driven interfaces which typically require VT100 terminal emulation,
whilst some even support X-windows.


INFORMATION SERVICES

Archie is a way of finding files on the 900 or so sites which participate
in keeping the Archie database updated - most of the major anonymous ftp
sites contribute to the database.  The main archie server in the UK is
'archie.doc.ic.ac.uk' at Imperial College - telnet in and log in as
'archie' (no password required), then type 'help'.

The most commonly-used Archie command is 'prog' which searches the
database for site holding particular files (not, as you might
expect, programs - obviously written by someone who is a fan of Unix's
legendary obscurity).  The search may be of type 'exact' (exact match
including case), 'regex' (Unix regular expression), 'sub' (files
found which contain the search string) and 'subcase' (like sub, but
case-sensitive).  The most useful is probably 'sub', although different
Archies default to different search types so you may need to use 'set'
search sub}.  You are likely to get a VERY large listing of
matches, and you will come to realise just how frequently the same names
are used for entirely different programs on different machines.

Archie also has a database of descriptions for some packages, which can be
searched for matching words by the 'whatis' command.  Unfortunately,
whilst participating ftp sites update the file list (used by 'prog')
automatically every month, the descriptive database is compiled by
hand - it is nowhere near as complete as the file list, and may even
contain information which is no longer valid.

Gopher is a menu-driven tool which simplifies the task of searching on-line
resources, regardless of their type.  Gopher provides a 'one-stop' way of
examining existing information services like Archie, ftp archives, library
catalogues and databases.  You follow the menus until you find what you
want, then gopher will 'go fer' it.  Gopher is relatively new, so not all
information services support it yet, and if your connection software
doesn't handle gopher directly you will find that a telnet to a gopher
server can be very slow.

WAIS (wide area information services) is an indexed database of textual
information on the Internet - articles in the database can be searched for
keywords or combinations of keywords, and WAIS returns a list of likely
articles together with a 'score' indicating how closely they match the
search criteria.  Like gopher, WAIS is relatively new and not all archives
and libraries support it.  WAIS tends to be window-driven and performs best
if your software supports it directly, although there are servers offering
a command-line variant called 'swais' which you can telnet to.

WWW (World-Wide Web) is a hypertext browser - highlighted words in a
document have 'links' elsewhere (the link could point to another part of
the same document or another document, even another document half-way
around the globe).  You can ask WWW to 'expand' a highlighted word (follow
the link): if you are reading an article about the Archimedes the word
'RISC' might be highlighted - following the link may take you to an article
on RISC micro-processors.  As yet there is little hypertext material on the
Internet, but this will increase with time.  You really need X-windows to
use WWW to full advantage, but there are command-line versions.

Many universities have computerised library catalogues, and a large number
choose to make these available over the Internet.  You can also access the
US Library of Congress records and various collections of legal data,
amongst others.  A number of sites provide satellite weather maps for ftp.
You can use finger to find out the latest goings on at NASA, or information
on recent earthquakes.  Whatever your interest you can probably find
information on it somewhere on the Internet.


TIME-WASTERS

Internet Relay Chat is similar in concept to BBS multi-user chats, except
that there are many separate 'channels' to choose from.  IRC is a great way
of running up phone bills - if you want to boost BT's profits then telnet
to 'irc.demon.co.uk'.

Multi-User Dungeons are multi-player adventure games - very addictive and
likely to result in bankruptcy when the phone bill comes in.  It is
rumoured that DIS will implement a MUD in the near future.


DIS

Following the appearance of the UK's second commercial Internet provider
(Pipex) Demon Systems (a computer systems supplier) saw the possibility of
leasing a feed from Pipex and selling connections to individual customers.
After initial discussion in the 'tenner-a-month' conference on CIX, Demon
Internet Services went live in June 1992 with 110 sites (many of whom paid
a year in advance to help get things off the ground) and 8 lines.  DIS
hoped to have at least 200 sites at the end of the first year - 13 months
on and they have 1,785 active sites growing at the rate of approx 170
sites/month, served by 32 lines in London, 8 in Warrington and 8 in
Edinburgh.  Additional 'Points of Presence' (PoPs) will appear in
other major population centres as soon as revenues permit.

DIS's rapid growth rate and high traffic caused problems with Pipex, and
after a brief flirtation with EUnet GB (the UK's first commercial Internet
provider) DIS installed their own direct line to the US and became the UK's
third commercial Internet provider.  This rapid growth has also resulted in
occasional hiccups causing one or more services to run exceedingly
slowly - DIS solve this by either throwing faster hardware at it or
rewriting the software (existing software is designed to service around a
dozen sites and 'scales' badly when this number is exceeded).

DIS offer telphone support Mon-Fri 9am-9pm, Sat 9am-6pm when they will
answer any questions.  Unfortunately, they don't know much about the Arc
(they recently bought a second-hand Mac in order to support that machine
better, so there's hope for us yet).  They may also be called at
any time to report a problem with the DIS service, but outside of
support hours you'd better be sure it's not your end that's at fault...

As well as the 'tenner-a-month' service, there are a number of options more
suited to commercial sites including dedicated- and leased-lines.  DIS also
sell Miracom (USR) modems quite cheaply and are distributors for
Addison-Wesley books.

DIS may be contacted at

Demon Internet Services
42 Hendon Lane
London
N3 1TT
Tel: [phone]
E-mail: [e-mail]


SOFTWARE

The software used to connect to DIS is called 'ka9q' (named after the
call-sign of the US radio ham who wrote it so he could use his PC for
amateur packet-radio which uses the TCP/IP protocols); Acorn's TCP/IP
package is NOT suitable as it does not support the serial port.
Ka9q has been added to over the years, but the Archimedes version is still
rather antiquated - an old version was ported over to the Arc by Jonathan
Naylor so he could use packet radio.  Anthony Frost found it could be used
with DIS and modified it in a number of ways, Jonathan later joined DIS and
contributed further modifications.  Even so, ka9q for the Arc lacks some of
the cleverer bits of its PC counterpart and is therefore somewhat limited
(but there are often work-arounds).  Worse still, it retains the PC concept
of 'sessions' where the window is manually switched between (say) ftp and
telnet - it would be more natural to have a separate window for each
session.  All in all, ka9q is difficult to come to terms with and may be
off-putting for the technically naive.  Jonathan no longer has an Arc,
but Anthony works on improving ka9q as and when time permits - if you think
you can do it better you're welcome to try.  The latest version of
Archimedes ka9q can be found on Arcade BBS or may be ftp'd from 'gate'
in directory '/pub/archimedes': it supports the serial block-drivers and
can pipe its I/O through a comms program (RISC OS3 only) to provide terminal
emulation required for some of the more advanced Internet services.

Users with older hardware (A300/A400/A540/A3000), RISC OS 3.1 and some
third-party hard discs may find that the serial port loses characters at
higher data rates - the maximum usable rate may be as low as 2400 bps,
although 9600 bps is more common.  There is an unofficial patch available
from the Plasma Sphere BBS and there are rumours of an official Acorn patch
'available from dealers'.  Both seem to fix the problem, although there may
still be difficulties with high-bandwidth screen modes.  I do wish that
Acorn were more open about bugs, and made bugfixes more readily
available - magazine discs, BBSs, Internet and PD libraries spring to mind
as low-cost ways of making fixes widely available.  I also happen to
believe that not making the serial port patch available on BBSs, whose
users are most in need of it, is the height of folly.

Ka9q is responsible for sending and receiving e-mail and news.  E-mail is
put into named mailboxes whilst news is collected in a large file.  Both
can be read with a text editor, but this is far from ideal.  To prepare
outgoing messages requires some knowledge of ka9q internals, so most people
use a Mailer or Newsreader.  The mailer which accompanies ka9q (sometimes
Anthony forgets to include it) is called BM - it doesn't handle news and is
pretty dire, but it gets you started.  Anthony has a Careware mailer /
newsreader called ReaderS which costs £10 (most of which goes to the
RNLI and Cornwall Air Ambulance Trust).  A cut-down version (it won't keep
an archive of messages) called Reader is currently being enhanced to work
with DIS.  For the past year I've been using the PD ReadNews, together with
a couple of home-brew programs to let it work with ka9q and for the same
length of time I've been promising to tidy the programs up to the point
that I can release them publicly - some day I may actually get around to
it.  ReaderS and ReadNews have different strengths and weaknesses (both are
about to undergo major surgery which will rectify the weaknesses) - some
people prefer one and some the other.


HARDWARE REQUIREMENTS

Basically, the faster your modem the lower your telephone bill.  If you
live within a local call of one of the PoPs and take only a few low-traffic
newsgroups then 2400 bps may be adequate.  If you are a long-distance call
away and download a lot of news then a fast modem with V32bis compression
will pay for itself quite quickly.  With the older machines which can only
go up to 19200 bps a fast serial port might also be a wise investment (the
dual serial port card sold by 'The Serial Port' uses serial chips
with internal 16-byte buffers which allow operation up to 57600 bps and
eliminate the RO3 serial port problem).  Note that the effective data
transfer rate will be lower than the connection speed due to the protocol
overheads of TCP/IP, bandwidth limitations of links and the loading on the
remote computer.


CONCLUSION

The Internet can either be a treasure trove of information or a waste of
money - it depends entirely on your needs and whether or not the Internet
can satisfy them.  You may even find that some of the things it offers
(like Usenet News) satisfy needs you never knew you had.  Before rushing
out to join up, you should realise that the Internet was never designed for
hobbyist use - BBSers and users of 'hand-holding' services like Compulink
or CIX will likely experience some degree of culture shock.  Nobody offers
you files on a plate with nice menus or guarantees that what you want will
be there; you have to do much of the work yourself (but the no-frills
approach also means a cheaper service).

Those who encountered JANet and/or the Internet at university will have
little difficulty deciding whether or not DIS is for them.  Those with
modems can try it for a few months without breaking the bank.  Those
without a modem and on tight budgets will need to give it more careful
consideration, perhaps first buying a cheap modem and exploring BBSs before
venturing onto the Internet.


FURTHER INFORMATION

Arcade BBS in London has several DIS subscribers in its ranks, and most are
happy to offer information and guidance on getting to grips with using DIS.

A beginner's guide to Internet usage and 'netiquette' can be found in
'Zen and the Art of the Internet' by Brendan P. Kehoe.  This is an
electronic document distributed as both 'TeX' source and PostScript
output.  It is available by ftp from a large number of sites.

A very useful book which takes the reader all the way from getting started
to mastering everything the Internet has on offer is 'The Whole
Internet: User's Guide and Catalog' by Ed Krol, available from DIS for
£18.95 plus £2.50 p&p.  Whether you're undecided about subscribing to DIS,
or want to find out how to get the most out of your Internet connection,
this book is a must.

Anyone contemplating delving deeper into the Internet should take a look at
the RFCs held by DIS which may be ftp'd from 'gate' from directory 'rfc'.
Some RFCs are also aimed at new users and are given FYI (For Your
Information) numbers.

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Paul is an Internet junkie who suffers withdrawal symptoms if he doesn't
get his daily 0.5 MB fix of Usenet news..
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