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Posted by cwdjrxyz on 08/09/07 16:54
On Aug 8, 11:31 pm, William Gill <nore...@example.invalid> wrote:
> > I agree with cyw-whatever, though, that it's not a good deal, -at least in
> > the US. Furthermore, 512 kbps isn't particularly "hi-speed" for hi-speed
> > connections, anyway. I'd hold out for something better.
>
> "hi-speed" is relative. When I first started engineering data circuits
> anything above 1200 baud was considered "hi-speed." I know some folks
> in the podunks that would love to get 512 kbps.
I can remember when about 300 baud was usual for connection of a
terminal to a house mainframe. I used a minicomputer(which was not so
small in physical size and had core memory) to automate the collection
of data from an instrument. It mainly advanced angle by increments of
a few seconds of one degree and determined x-ray intensity at each
angle. The time for data collection at each point was rather long, so
the instrument ran full time. Intensity data was recorded vs angle on
an audio cassette tape on the terminal. I had to program the mini
computer in octal. It controlled and monitored about 20 things
including advancement of a micrometer, cooling water temperature for
the target of the x-ray tube, a scintillation counter, etc. When data
collection was complete, the terminal was switched to the line to the
house mainframe and the data collected on the tape was sent at about
300 baud. This was a case of a reasonable amount of data and huge
computing requirements. The data had to be processed using matrix
inversion of huge 2 dimensional arrays at each point for which a
parameter was varied. The computing demands were so large that my
program caused the whole house computing network to slow down greatly,
and calculations took over 1/2 hour. The computer finally printed out
results on the printer at the computer center. About that time people
started using crude CRT terminals as well as text terminals. Also HD
storage devices were beginning to be used, although they were very
expensive and had very low storage capacity by today's standards.
The internet was then still in the future. Sometimes the computer
center personnel would arrange to connect our house computer to
another computer via telephone. The transfer rate of data via
telephone then was quite small, but I do not recall what it was. Those
who had need for high transfer rate used microwave. At that time, Bell
telephone had microwave towers all over the country for long distance,
data services, TV, etc. Of course this service was very expensive,
because the microwave transmission was line-of- sight, so a huge
number of tall microwave towers had to be built all over the country.
This network of Microwave towers was replaced by C-band and Ku-band
satellites as well as fiber optics lines.
Today the goal is to increase speed enough so that TV can be
transmitted in real time at DVD and recently HD DVD standards as well
as normal web pages, telephone services, etc. This will require fiber
optics directly to the computer, not just via fiber optics to a
distribution line that has a conventional cable leading to each house
or business. This has been done on an experimental basis. When you
consider that over 10 Mbps is needed for DVD quality digital signals,
even more for HD ones, and more bandwith will be required for other
services, it is easy to see that it will be several years before such
services are available in most areas at a price that people will be
willing to pay.
For those who live beyond to reach of broadband now, a service with a
dialup telephone link and a satellite broadband download link is
available all over the US and in other places. Often one located in
areas that broadband does not reach has a small dish or a large dish C
- Ku band antenna for TV that will work without having to buy a new
antenna. Although the service is more expensive that most cable and
DSL delivered broadband, and often is slower in download, if there is
no other choice, many are willing to pay the price. Services with a
satellite link for upload also are available, but these are quite
expensive and are most likely to attract business and news
organization users.
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