Sep 18, 2007

BandWidth Explained

This is well written explanation about bandwidth.

Most hosting companies offer a variety of bandwidth options in their plans. So exactly what is bandwidth as it relates to web hosting? Put simply, bandwidth is the amount of traffic that is allowed to occur between your web site and the rest of the internet. The amount of bandwidth a hosting company can provide is determined by their network connections, both internal to their data center and external to the public internet.


Network Connectivity

The internet, in the most simplest of terms, is a group of millions of computers connected by networks. These connections within the internet can be large or small depending upon the cabling and equipment that is used at a particular internet location. It is the size of each network connection that determines how much bandwidth is available. For example, if you use a DSL connection to connect to the internet, you have 1.54 Mega bits (Mb) of bandwidth. Bandwidth therefore is measured in bits (a single 0 or 1). Bits are grouped in bytes which form words, text, and other information that is transferred between your computer and the internet.

If you have a DSL connection to the internet, you have dedicated bandwidth between your computer and your internet provider. But your internet provider may have thousands of DSL connections to their location. All of these connection aggregate at your internet provider who then has their own dedicated connection to the internet (or multiple connections) which is much larger than your single connection. They must have enough bandwidth to serve your computing needs as well as all of their other customers. So while you have a 1.54Mb connection to your internet provider, your internet provider may have a 255Mb connection to the internet so it can accommodate your needs and up to 166 other users (255/1.54).


Traffic

A very simple analogy to use to understand bandwidth and traffic is to think of highways and cars. Bandwidth is the number of lanes on the highway and traffic is the number of cars on the highway. If you are the only car on a highway, you can travel very quickly. If you are stuck in the middle of rush hour, you may travel very slowly since all of the lanes are being used up.

Traffic is simply the number of bits that are transferred on network connections. It is easiest to understand traffic using examples. One Gigabyte is 2 to the 30th power (1,073,741,824) bytes. One gigabyte is equal to 1,024 megabytes. To put this in perspective, it takes one byte to store one character. Imagine 100 file cabinets in a building, each of these cabinets holds 1000 folders. Each folder has 100 papers. Each paper contains 100 characters - A GB is all the characters in the building. An MP3 song is about 4MB, the same song in wav format is about 40MB, a full length movie can be 800MB to 1000MB (1000MB = 1GB).

If you were to transfer this MP3 song from a web site to your computer, you would create 4MB of traffic between the web site you are downloading from and your computer. Depending upon the network connection between the web site and the internet, the transfer may occur very quickly, or it could take time if other people are also downloading files at the same time. If, for example, the web site you download from has a 10MB connection to the internet, and you are the only person accessing that web site to download your MP3, your 4MB file will be the only traffic on that web site. However, if three people are all downloading that same MP at the same time, 12MB (3 x 4MB) of traffic has been created. Because in this example, the host only has 10MB of bandwidth, someone will have to wait. The network equipment at the hosting company will cycle through each person downloading the file and transfer a small portion at a time so each person's file transfer can take place, but the transfer for everyone downloading the file will be slower. If 100 people all came to the site and downloaded the MP3 at the same time, the transfers would be extremely slow. If the host wanted to decrease the time it took to download files simultaneously, it could increase the bandwidth of their internet connection (at a cost due to upgrading equipment).


Hosting Bandwidth

In the example above, we discussed traffic in terms of downloading an MP3 file. However, each time you visit a web site, you are creating traffic, because in order to view that web page on your computer, the web page is first downloaded to your computer (between the web site and you) which is then displayed using your browser software (Internet Explorer, Netscape, etc.) . The page itself is simply a file that creates traffic just like the MP3 file in the example above (however, a web page is usually much smaller than a music file).

A web page may be very small or large depending upon the amount of text and the number and quality of images integrated within the web page. For example, the home page for CNN.com is about 200KB (200 Kilobytes = 200,000 bytes = 1,600,000 bits). This is typically large for a web page. In comparison, Yahoo's home page is about 70KB.


How Much Bandwidth Is Enough?

It depends (don't you hate that answer). But in truth, it does. Since bandwidth is a significant determinant of hosting plan prices, you should take time to determine just how much is right for you. Almost all hosting plans have bandwidth requirements measured in months, so you need to estimate the amount of bandwidth that will be required by your site on a monthly basis

If you do not intend to provide file download capability from your site, the formula for calculating bandwidth is fairly straightforward:

Average Daily Visitors x Average Page Views x Average Page Size x 31 x Fudge Factor

If you intend to allow people to download files from your site, your bandwidth calculation should be:

[(Average Daily Visitors x Average Page Views x Average Page Size) +
(Average Daily File Downloads x Average File Size)] x 31 x Fudge Factor

Let us examine each item in the formula:

Average Daily Visitors - The number of people you expect to visit your site, on average, each day. Depending upon how you market your site, this number could be from 1 to 1,000,000.

Average Page Views - On average, the number of web pages you expect a person to view. If you have 50 web pages in your web site, an average person may only view 5 of those pages each time they visit.

Average Page Size - The average size of your web pages, in Kilobytes (KB). If you have already designed your site, you can calculate this directly.

Average Daily File Downloads - The number of downloads you expect to occur on your site. This is a function of the numbers of visitors and how many times a visitor downloads a file, on average, each day.

Average File Size - Average file size of files that are downloadable from your site. Similar to your web pages, if you already know which files can be downloaded, you can calculate this directly.

Fudge Factor - A number greater than 1. Using 1.5 would be safe, which assumes that your estimate is off by 50%. However, if you were very unsure, you could use 2 or 3 to ensure that your bandwidth requirements are more than met.

Usually, hosting plans offer bandwidth in terms of Gigabytes (GB) per month. This is why our formula takes daily averages and multiplies them by 31.


Summary

Most personal or small business sites will not need more than 1GB of bandwidth per month. If you have a web site that is composed of static web pages and you expect little traffic to your site on a daily basis, go with a low bandwidth plan. If you go over the amount of bandwidth allocated in your plan, your hosting company could charge you over usage fees, so if you think the traffic to your site will be significant, you may want to go through the calculations above to estimate the amount of bandwidth required in a hosting plan.

Sep 11, 2007

Computer Maintenance

You may not realize it, but your computer and your car have something in common: they both need regular maintenance. No, you don't need to change your computer's oil. But you should be updating your software, keeping your antivirus subscription up to date, and checking for spyware. Read on to learn what you can do to help improve your computer's security.


Getting started


Here are some basics maintenance tasks you can do today to start improving your computer's security. Be sure you make these part of your ongoing maintenance as well.

* Sign up for software update e-mail notices. Many software companies will send you e-mail whenever a software update is available. This is particularly important for your operating system (e.g., Microsoft Windows or Macintosh), your antivirus program, and your firewall.

* Register your software. If you still have registration forms for existing software, send them in. And be sure to register new software in the future. This is another way for the software manufacturer to alert you when new updates are available.

* Install software updates immediately.
When you get an update notice, download the update immediately and install it. (Remember, downloading and installing are two separate tasks.)

An ounce of prevention

A few simple steps will help you keep your files safe and clean.


* Step 1: Update your software
* Step 2: Backup your files
* Step 3: Use antivirus software and keep it updated
* Step 4: Change your passwords


Developing ongoing maintenance practices

Now that you've done some ground work, it's time to start moving into longer term maintenance tasks. These are all tasks that you should do today (or as soon as possible) to get started. But for best results, make these a part of a regular maintenance schedule. We recommend setting aside time each week to help keep your computer secure.

* Back up your files. Backing up your files simply means creating a copy of your computer files that you can use in the event the originals are lost. (Accidents can happen.) To learn more read our tips for backing up information.


* Scan your files with up to date antivirus software. Use your antivirus scan tool regularly to search for potential computer viruses and worms. Also, check your antivirus program's user manual to see if you can schedule an automatic scan of your computer. To learn more, read our tips for reducing your virus risk
.
* Change your passwords. Using the same password increases the odds that someone else will discover it. Change all of your passwords regularly (we recommend monthly) to reduce your risk. Also, choose your passwords carefully. To learn more, read our tips for creating stronger passwords
.

Making a schedule

One of the best ways to help protect your computer is to perform maintenance regularly. To help you keep track, we suggest making a regular "appointment" with your computer. Treat it like you would any other appointment. Record it in your datebook or online calendar, and if you cannot make it, reschedule. Remember, you are not only helping to improve your computer, you are also helping to protect your personal information.


Sep 7, 2007

DVD Regions Information

The DVD region code identifies a DVD's compatibility with the players typically sold in a particular region.

The following graphic shows the approximate location of each region.

Region 0 (or "region free") is compatible with DVD players from any region.

The majority of all current titles play only in one specific region unless otherwise noted. DVDs sold by Amazon.co.uk are encoded for Region 2 or Region 0. Region 2 DVDs may not work on DVD players in other countries.

Region 1 DVDs sold by Marketplace sellers

Region 1 discs are intended for use with standard DVD players in North America (Canada and the USA). In most instances they can also be played on compatible "multi-region" DVD players (also known as "chipped" or "region-free" players).

They also require an NTSC-compatible television. NTSC is the standard picture format in North America, and differs from the PAL format adopted in Britain and Europe. Region 1 DVDs are usually presented in NTSC format, so you should ensure that your TV is capable of reading the NTSC signal before purchasing Region 1 DVDs.

Regional Coding Enhancement (RCE)

Regional Coding Enhancement (RCE) has been added by some film studios (specifically Warner and Columbia) to selected Region 1 DVDs, with the intention of preventing these discs from playing on some multi-region DVD players. We are therefore unable to guarantee that all Region 1 discs will be compatible with all multi-region players.

Global DVD region countries

This is not a definitive list and is intended only as a guide.

Region 1 - US, US Territories and Canada

American Samoa, Canada, Guam, Palau, Mariana Islands, Marshall Islands, Puerto Rico, Micronesia, United States, U.S. Virgin Islands

Region 2 - UK, Europe, Japan, South Africa and Middle East

Albania, Andorra, Austria, Bahrain, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Egypt, Finland, France, Germany, Gibraltar, Greece, Greenland, Hungary, Iceland, Iran, Iraq, Ireland, Israel, Italy, Japan, Jordan, Kuwait, Lebanon, Liechtenstein, Luxembourg, Macedonia, Malta, Moldova, Monaco, Netherlands, Norway, Oman, Poland, Portugal, Qatar, Romania, San Marino, Saudi Arabia, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Syria, United Arab Emirates, United Kingdom, Vatican City, Yemen, Yugoslavia

Region 3 - Southeast and East Asia

Cambodia, Hong Kong, Indonesia, Laos, Malaysia, Myanmar, Phillipines, South Korea, Taiwan, Thailand, Vietnam

Region 4 - Australia, New Zealand, Central and South America

Antigua, Argentina, Aruba, Australia, Bahamas, Barbados, Barbuda, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominica, Dominican Republic, Ecuador, El Salvador, Falkland Islands, French Guiana, Grenada, Guatemala, Guyana, Haiti, Honduras, Jamaica, Mexico, New Guinea, New Zealand, Nicaragua, Panama, Paraguay, Peru, Suriname, Trinidad, Tobago, Uruguay

Region 5 - Former Soviet Union, Indian sub-continent, Africa, North Korea and Mongolia

Afghanistan, Algeria, Angola, Bangladesh, Belarus, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Congo, Djibouti, Equatorial Guinea, Eritrea, Estonia, Ethiopia, Gabon, Gambia, Georgia, Ghana, Guinea, Guinea-Bissau, India, Ivory Coast, Kazakhstan, Kenya, Latvia, Lesotho, Liberia, Libya, Lithuania, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mongolia, Morocco, Mozambique, Namibia, Niger, Nigeria, North Korea, Pakistan, Russia, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, Sri Lanka, St. Helena, Sudan, Tanzania, Togo, Tunisia, Turkmenistan, Uganda, Ukraine, Uzbekistan, Zambia, Zimbabwe

Region 6 - China

Region 7 - Reserved for future use

Region 8 - International Territories (ships, planes, etc)
Google