Language:
SEARCH

internet

From tarred hemp and Indian rubber to optical fibre

Friday, November 20th, 2015

The internet began to emerge in the late 1980s and early 90s. However, the infrastructure supporting it has been around since 1839.

Today most of our Internet traffic is carried via submarine cable systems from Europe and the United States.

A submarine communications cable is a laid on the seabed between land-based stations to carry telecommunication signals across stretches of ocean. Before internet, however, submarine cables were used for other types of communications, for example telephones and telegraph.

After the introduction of the telegraph in 1839, establishing a submarine line across the Atlantic Ocean became the next challenge. Samuel Morse accepted this challenge and in 1842 he succeeded in sending a telegraph through a wire insulated with tarred hemp and Indian rubber, which was submerged in the water of New York Harbour.

Laying-undersea-cable-Cape-Town
Laying an undersea cable in Cape Town (Photo credit: Telkom)

The first submarine cable system in South Africa was launched in on 27 December 1879 and for the first time we were directly connected to Europe. This was done via Durban and Zanzibar to Aden with the East Coast cable of the South African Telegraph Company.

Today’s cables use optical fibre technology to carry digital data, which includes telephone, Internet and private data traffic.

“Modern cables are typically about 25 millimetres in diameter and weigh around 1.4 kilograms per metre for the deep-sea sections which comprise the majority of the run, although larger and heavier cables are used for shallow-water sections near shore.” (https://en.wikipedia.org/wiki/Submarine_communications_cable)

Over the past 15 years four submarine cable systems have been installed in South Africa for telecommunication – SAT-3/WACS, Seacom, WACS, and EASSy.

The most recent addition was made in May 2012 with the West Africa Cable System (WACS). The 17 200 km fibre optic submarine cable starts at Yzerfontein on the west coast and ends in the United Kingdom. (More about the WACS launch)

[SOURCES: www.mybroadband.co.za & https://en.wikipedia.org]

Lower internet rates and faster internet

Wednesday, February 6th, 2013

Thanks to the University’s collaboration with SANREN and the implementation of the new Fortigate firewall, users on campus can now look forward to lower internet rates and faster, more stable internet. Both these projects were necessary if one takes into consideration that the university’s bandwidth usage doubled each year for the past 8 years. In spite of the increase in usage, rates were never increased.

 

RATES FOR INTERNET USAGE FROM 1 JANUARY 2013

Tariff A @R0.02/MB: Monday-Friday: 08h00-23h59

Tariff B @ R0.01/MB : Monday-Friday: 00h00-07h59, as well as Saturdays and Sundays

 

Take note that the relevant tariff is determined by the day and time the download process was completed.

•Example 1: If you start downloading a file of 3 MB at 16:55 on Monday and the download is completed at 17:10 (Monday), the tariff for Monday 17:10 will apply.

•Example 2: If the same file is downloaded from Monday 07:55 to Monday 08:10, the tariff for Monday 08:10 will apply.

 

 

Mirror sites at your disposal

Friday, June 8th, 2012

Did you know there are selected websites you have free access to? These websites are known as mirror sites.

In computing, a mirror is an exact copy of a data set. On the Internet, a mirror site is an exact copy of another Internet site. Mirror sites are most commonly used to provide multiple sources of the same information, and are of particular value as a way of providing reliable access to large downloads. Mirroring is a type of file synchronization and a  live mirror is automatically updated as soon as the original is changed.

But why the need for more than one version of the same website. A few reasons are:

  1. To preserve a website or page, especially when it is closed or is about to be closed.
  2. To allow faster downloads for users at a specific geographical location. For example, a U.S. server could be mirrored in Japan, allowing Japanese Internet users to download content faster from the local Japanese server than from the original American one.
  3. To provide access to otherwise unavailable information. For example, when the popular Google search engine was banned in 2002 by the People’s Republic of China, the mirror elgooG was used as a way of effectively circumventing the ban.
  4. To preserve historic content. Financial constraints and/or bandwidth prevent the maintainers of a server from keeping older and unsupported content available to users who still may desire them; a mirror may be made to prevent this content from disappearing.
  5. To balance load. If one server is extremely popular a mirror may help relieve this load this server may become overloaded with demand. Alternative download points allow the total number of download requests to be spread among several servers, maintaining the availability of the distribution.
  6. As a temporary measure to counterbalance a sudden, temporary increase in traffic.

SOURCE: www.wikipedia.org

Therefore, before you download huge files from an international server and run up an exorbitant internet account, check whether there is a local version available. The following websites are available to you free of charge:

A large amount of software downloads are available at http://support.sun.ac.za

MIT OpenCourse Ware: http://ocw.sun.ac.za

Mirror server for linux: http://ftp.sun.ac.za

Mirror services available for free via TENET: http://www.mirror.ac.za

The most popular Linux distros are available (Ubuntu,Debian, Fedora, Opensuse, Mandriva etc.)

Complete programming language mirrors are availabla at:

CPAN (perl): http://ftp.sun.ac.za/ftp/pub/mirrors/ftp.funet.fi/pub/languages/perl/CPAN/

CTAN (Tex/Latex): http://ftp.sun.ac.za/ftp/pub/mirrors/ftp.dante.de/tex-archive/

Python: http://ftp.sun.ac.za/ftp/pub/mirrors/ftp.python.org/

Mathematical languages:

SageMath: http://ftp.sun.ac.za/ftp/pub/mirrors/www.sagemath.org/

Scilab (http://ftp.sun.ac.za/ftp/pub/mirrors/scilab/www.scilab.org/

http://ftp.sun.ac.za/ftp/pub/mirrors/cran.za.r

Octava http://ftp.sun.ac.za/ftp/pub/mirrors/octave

Opensource software:

sourceware.org: http://ftp.sun.ac.za/ftp/pub/mirrors/sourceware.org/pub/

Free Office packages:

LibreOffice: http://ftp.sun.ac.za/ftp/pub/mirrors/libreoffice/

OpenOffice: http://ftp.sun.ac.za/ftp/pub/mirrors/openoffice/

Downloadable antivirus updates:

Mcafee: http://ftp.sun.ac.za/ftp/pub/mirrors/ftp.nai.com/

Symantec: http://ftp.sun.ac.za/ftp/pub/mirrors/ftp.symantec.com
/public/english_us_canada/antivirus_definitions/norton_antivirus/

Adobe Reader: http://ftp.sun.ac.za/ftp/pub/mirrors/ftp.adobe.com/

SOURCE:  www.wikipedia.org

Too many line options to choose from?

Thursday, June 7th, 2012

Nowadays we’re fortunate (depending on our budgets of course) to have internet access at home. We can quickly Google a recipe instead of scurrying to find the right cookbook or piece of paper you wrote the recipe down on somewhere. Or quickly look up the name of that actor whose name is on the tip of your tongue and you’re convinced your husband has the wrong one.

Unfortunately being spoilt for choice also brings more confusion at times. On top of having to choose the right service provider, you can also choose your line speed.  iAfrica  explained it for us in simple terms.

SOURCE: www.iafrica.com

Broadband or Big Mac?

Friday, May 25th, 2012

Broadband prices plummeted over the last decade, but the same cannot be said for many other products. Rudolph Muller from www.mybroadband.co.za investigated and stumbled upon a few interesting numbers.

ADSL and mobile data prices have plunged over the last decade. The total cost of an ADSL service dropped by over 50% since it was launched in 2002 while mobile data costs decreased by 96% over the last 10 years.

In 2002 a basic 512 Kbps ADSL service cost residential customers R966.72 per month (R67.72 for analogue line rental, R680 for ADSL access and R219 for a 3GB data bundle). In comparison, the price for a 384kbps connection with 5GB of data is now priced at R358.97 (R219.00 + R139.97).

Even more significant price cuts are visible in the mobile data market. In 2002 a 10MB data bundle from Vodacom cost R200 (hence R20 per MB). Today users can buy a 1GB data bundle from the same company for R99 (10c per MB).

Broadband prices have seen price cuts of between 50% and 95% over the last decade. These price reductions were partly fuelled by lower international bandwidth prices made possible by SEACOM.

When compared with products such as petrol and food, broadband stands out as having bucked the trend of price increases.

The following table provides an overview of the price changes of a few products over the last 10 years.

Service 2002 2012 Change

Telkom ADSL

Consumer ADSL access (512kbps/1Mbps) R680 R289 -58%
Business ADSL access (512kbps/1Mbps) R800 R289 -64%
3GB of blended ADSL data R219 R59.4 -73%
Analogue line rental R68 R140 107%

Vodacom mobile data

Out of bundle R45 R2 -96%
MyMeg 10 R200 R9 -96%

MultiChoice pay-TV

DStv premium R349 R590 69%

Fuel

Petrol R4.26 R11.77 176%

Big Mac

McDonald’s Big Mac burger R9.00 R20.95 133%
 

© 2013-2017 Disclaimer: The views and opinions expressed in this page are strictly those of the page author(s) and content contributor(s). The contents of this page have not been reviewed or approved by Stellenbosch University.