Computing for the Bewildered. By Bill Hayles
Hello again.
Before I start, a clarification. Data transfer speeds are sometimes
measures in kilobits per second, and sometimes kilobytes per second.
8 kilobits per sesond equal one kilobyte. Where I use the abbrevation
kbs, I mean kilobits per second.
In 1997, the PC world was, as it is now, full of new developments. If
you had enough money, you could buy the latest bells-and-whistles
computer with 32Mb of RAM powered by a Pentium 166 Mhz processor. It
could well have one of Seagate's 2.5Gb hard drives, and the operating
system would be Windows95, which in its OSR2 version finally
acknowledged the existence of the Internet that Microsoft had hitherto
tried hard to pretend didn't exist. To connect to the Internet, you
would use a 56kbs (kilobits per second) modem. We've come a long way in
the last five years - processors of over 1Ghz, 40 and even 80Gb hard
disks, RAM ten times faster and ten times greater in quantity, and the
latest offering from Redmond, Windows XP, which wouldn't even run on
your old P166. However, in one respect, time has stood still. The
performance of most people's Internet connections hasn't changed at all.
You are still using a 56kbs modem. OK, so it's smaller and cheaper
than the US Robotics Courier I bought all those years ago, and it may
be easier to install, but it won't hoover data off the net any faster.
It's not that the technology hasn't been available. For those
fortunate to live in an area where it is an option, cable modem has
been around for some years, but it hasn't been without its problems. It
is expensive, and not much faster than dial-up, especially at peak
times. Another solution appeared to be satellite - this has been
promoted for those areas without fixed land line telephones. But, quite
apart from the expense it has a big problem. Unless you are going to
set up your own satellite transmitting station, communication from your
end back to the Internet still has to be by good old telephone. This
has severely limited its appeal. Another solution, one I used myself
for quite some time, is by RDSI, or IDSN (Integrated Services Digital
Network) if you prefer. This is a digital dial-up connection, available,
unlike ADSL which I'm coming to, on virtually every Telefonica land
line (except, so I'm told, on Clive Read's!) It gives a dependable
64kbs. You need the installation of a special splitter box by
Telefonica, and you need a RDSI modem. Most of the Internet deals,
including "free" accounts are equally available for RDSI customers as
they are for normal analog customers, and you still pay for your
Internet phone calls, although you have the advantage that you can make
or receive a voice call at the same time. Therefore, RDSI has always
been a minority option and is set to decline even further as more and
more people sign up for ADSL.
So, what is this ADSL that I, and others, keep talking about? ADSL
stands for Asymmetric Digital Subscriber Line, which probably means
nothing to you, so let's keep it simple. If you have ADSL, your
Internet connection is completely independent of your telephone, even
though both come into the house through the same socket. You will have
a permanent (all the time your computer is on) connection to the
Internet at a maximum speed (normally and nominally) of 256kbs for
incoming data and 128kbs for outgoing. The speed difference is the
Asymmetric part of ADSL, and is of no real life importance since almost
everybody downloads far more from the Internet than they ever upload.
ADSL is set to transform Internet connections - it is (comparatively)
cheap, with a flat rate fee, always available and, in theory, much
faster than what has been available previously.
Telefonica have steadily been making their network ADSL capable. Most,
but not all, of the area covered by The Grapevine has been converted in
the last year. Things have improved rapidly recently. I applied for my
ADSL connection last November and finally got it earlier this month.
However, I know of people who, having applied within the last month,
already have their connection. There is a web site (links at the end)
where you can check the availability of ADSL for your own number, but
an even better way, if you want it, is to contact an ISP and ask them.
The major Spanish Internet Service Providers (including Telefonica
themselves) are competing vigorously for ADSL customers, with the
result that there are some really good deals around. If you want the
standard 256kbs/128kbs connection, and you're prepared to do your own
installation, then the extra hardware needed will be provided free of
charge.
My own ADSL contract is with Telefonica. Since the physical wire into
my house is still their responsibility irrespective of who my ADSL ISP
is, I reckon that if something goes wrong I'm in a good position as one
party won't be able to blame the other! Therefore, the details I'm
giving are for my connection through Telefonica. Prices seem to be
changing daily, so keep an eye on things and make sure you get a good
deal. In my own case, I had to have my RDSI connection disabled and my
line ADSL enabled. That cost me 32EUR on my phone bill. I was given
the router, some microfilters which enable me to use my voice phone
while I'm on line, a network card to fit inside my computer, all the
cables and some installation software. This all arrived by courier one
Thursday evening. A couple of weeks previously, I had received a
letter containing all my personal settings. I had no trouble installing
the router, configuring it and getting it to work. But then again, I'm
supposed to know what I'm doing! I think the average computer user
could, if they read and followed the instructions (in Spanish!)
carefully, get themselves connected. In any case, if you don't think
you can manage it, Telefonica (or Terra or Wanadoo) will arrange for
somebody to visit your house and install it for about 90EUR. From now
on, the cost of my Internet connection will be 42EUR a month. This
compares with 90EUR that I was paying Wanadoo for my Tarifa Plana (flat
rate) RDSI connection.
It all sounds wonderful, doesn't it! Surely, you must be thinking to
yourself, there must be some drawbacks. Yes, you're right, there are
three that I can think of. Firstly, you can't have more than one ADSL
connection. Unlike a dial-up or RDSI, you can't use your "spare"
account if your main one fails for any reason. Also, if you move house,
you will need to start all over again in your new one. The second
drawback is that the minimum contract is for 1 or in some cases 2 years.
Even if you don't use the service, you'll still have to pay the monthly
fee, and if you're not happy, you can't simply change providers. The
third second drawback is one that the ISPs are playing down, and which
certainly isn't an issue in these early days, but may well prove to be
a problem once ADSL becomes popular. The problem is that of contention.
When you connect by a dial-up or RDSI connection, the wire between your
house and the ISP is for your exclusive use. There may be congestion
from there forwards, but nobody else shares your phone line. With ADSL
this isn't the case. Think of your mains water supply. Normally, the
pressure at your house is reasonable, but if everybody in your area
turns their taps on at the same time the pressure will drop. That is
contention. You are contending with others in your area for the
available capacity of the water main. So it is with ADSL. Each
256kbs/128kbs line can be shared with others. For BT, the contention
ratio is declared to be a maximum of 50 to 1. In other words, if you
were all downloading at the same time, you would be sharing the 256kbs
connection with up to 49 others. Naturally, the system knows which
computer to send which data to, but the speed drops - as low as 5kbs in
theory. Telefonica, Wanadoo and Terra haven't (as far as I know)
declared a contention ratio. Instead, they have guaranteed a minimum
throughput of just 10% of the theoretical maximum, in other words
25.6kbs or, if you prefer, just over 3 kilobytes per second, or even
less than you can get through a dial-up. This is much less impressive
than the figure of 256kbs which is the theoretical maximum, or even the
20+ kilobytes pre second which I'm currently experiencing. However,
it's my guess that as more and more ADSL connections are enabled,
speeds will drop. Just how far remains to be seen.
If you want to know more about ADSL, including the various ISPs offers,
I have added a page to my website - http://billnot.com/adsl/adsl.html -
with links to other sites which go into the topic in great detail,
including a site where you can input your own number and see if ADSL is
available to you. There is also a downloadable version of the page, in
Rich Text Format
That's it for this month, but if you have a question you'd like me to
answer in the column,or maybe an idea for a topic, please e-mail it to
questions@billnot.com, If you don't have e-mail, you can always leave
your question at the CopiShop. However, I can't guarantee to answer
questions personally.