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Upcoming day, World Day of Social Justice, 20 February. 2020 Theme: "Closing the Inequalities Gap to Achieve Social Justice!"


Inform       Today is Tuesday, February 18, 2020 and day 049 of the year.

Dec 25, 2019 at 02:44 PM

የነገውን የከፊል የጸሃይ ግርዶሽን ለመከታተል የሚረዳ ካሜራ በቤትዎ ይስሩ

Informer : Askwala

የነገውን የከፊል የጸሃይ ግርዶሽን ለመከታተል ይህን ቀላል ፒን ሆል ካሜራ በመኖሪያ ቤታችን በሚገኙ ቁሳቁሶች መስራት ይቻላል:: \\r\\nለበለጠ መረጃ ከታች ያለውን የዩቱብ ሊንክ ይጫኑ\\r\\nIn order to view the upcoming partial solar eclipse, we can construct a pin hole camera with materials that are easily available at home 

Info source: Ethiopian Space Science Society

Nov 18, 2019 at 10:22 AM

Body mass index

Informer : Space

Get to know about your body mass index and weight status 

Info source: askwala

Jun 11, 2019 at 03:29 PM

Call for Thematic Research Proposals

Informer : Space

The Office of the Director for Research hereby announces the 7th round call for thematic research proposals for possible funding.

The thematic research proposal:

1. should be in line with the new research priority areas of the university
2. need to address a national problem with an overarching goal;
3. should be multi-disciplinary, extending across more than one college / department /institute/school;
4. should incorporate at least three sub-theme/research components addressing different aspects of a common problem;
5. should involve a minimum of two academic staff in one sub-theme;
6. should extend from knowledge to usable technology creation and have components that address the dissemination of outcomes of the research,
7. should be problem solving, inclusive of stakeholders, industry and end-users and;
8. should incorporate PhD and/or Master’s thesis topics.
Please note that the proposals will be reviewed by panel of experts and those proposals which attain grades above cut of point will be notified.

The last date for submission is July 30, 2019. Please submit your application package using AAU CONVERIS at research portal. For any technical assistance please communicate Mr. Biniyam Amsalu (ICT Business Application Development and Administration Team Leader) at or +251-912077039. 

Info source: Addis Ababa University

May 22, 2019 at 09:55 AM

What is World Wide Web (WWW)?

Informer : Wegen

TheWorld Wide Web(WWWor theWeb) is often confused with the Internet.
While the precursor to the Internet was originally created during the Cold War as
a way to link sections of the country together during an emergency, the actual term
“Internet” wasn’t used until the early 1970s. At that time, academic research institutions
developed the Internet to create better communication and to share resources. Later,
universities and research facilities throughout the world began using the Internet. In the
early 1990s, Tim Berners-Lee created a set of technologies that allowed information
on the Internet to be linked together through the use oflinks, or connections, in
documents. The language component of these technologies is Hypertext Markup
Language (HTML). A good source of information on the history of the Internet is
The Web was mostly text based until Marc Andreessen created the first graphical
Web browser in 1993, called Mosaic. This paved the way for video, sound, and photos
on the Web.
As a large group of interconnected computers all over the world, the Internet comprises
not only the Web, but also things likenewsgroups(online bulletin boards) and e-mail.
Many people think of the Web as the graphical or illustrated part of the Internet. 

Info source: HTML a Beginners Guide

May 22, 2019 at 09:49 AM

The Anatomy of a Web Site

Informer : Wegen

1. URLs
The fancy word for “Web address” isuniform resource locator, also referenced by its acronym
URL(pronounced either by the letters U-R-L or as a single word, “url,” which rhymes with
“girl”). If you haven’t heard a Web address referred to as a URL, you have probably seen one—
URLs start with http://, and they usually end with .com, .org, .edu, or .net. (Other possibilities
include .tv, .biz, and .info. For more information,
Every Web site has a URL. An example is The following
illustration shows another example of a URL, as it appears in a Netscape browser.
One part of a URL is thedomain name, which helps identify and locate computers on
the Internet. To avoid confusion, each domain name is unique. You can think of the domain
name as a label or a shortcut. Behind that shortcut is a series of numbers, called anIP Address,
which gives the specific address of where the site you are looking for is located on the Internet.
To draw an analogy, if the domain name is the word “Emergency” written next to the first aid
symbol on your speed dial, the IP Address is 9-1-1.
Businesses typically register domain names ending in a .com (which signifies a commercial
venture) that are similar to their business or product name. Domain registration is like renting
office space on the Internet. Once you register a domain name, you have the right to publish a
Web site under that name on the Internet for as long as you pay the rental fees.

2. Web Servers
Every Web site and Web page also needs a Web server. Quite simply, aWeb server
is a computer, running special software, which is always connected to the Internet.
When you type a URL into your Web browser or click a link in a Web page, you send a
request to the server that houses that information. It’s similar to the process that occurs when
you dial a phone number with your telephone. Your request “calls” the computer that contains
all the files necessary to show you the Web page you requested. The computer then “serves”
and displays all the pages to you, usually in your Web browser.

3. Sites
A URL is commonly associated with a Web site. You have seen plenty of examples on
billboards and in television the URL for Yahoo!’s Web
site; the URL for CBS’s Web site.
Most commonly, these sites are located in directories or folders on the server, just as you
might have your C: drive on your personal computer. Then, within this main site, there may be
several folders, which house other sections of the Web site.
For example, Chop Point is a summer camp and K-12 school in Maine. It has several main
sections of its Web site, but the most notable are “camp” and “school.” If you look at the URL
for Chop Point’s camp section, you can see the name of the folder after the site name: If you were to look at the main page for the school, the URL changes to:

4. Pages
When you visit a Web site, you look at pages on the site that contain all the text, graphics,
sound, and video content. Even though a Web page is not the same size or format as a printed
page, the word “page” is used to help us differentiate between pages, folders, and sites. Just
as many pages and chapters can be within a single book, many pages and folders (or sections)
can also be within a Web site.
Most Web servers are set up to look automatically for a page called “index” as the main
page in any folder. So, if you were to type in the URL used in the previous example, the server
would look for the index page in the “camp” folder.
If you want to look for a different page in the camp folder, you could type the name of
that page after the site and folder names, keeping in mind that HTML pages usually end with

7 Comment(s)

Info source: HTML a Beginners Guide

May 11, 2019 at 05:19 PM

Building an Easy-to-Maintain Web Site with Free Tools

Informer : Wegen

You need to set up a small web site and are willing to sacrifice some customization options in favor of saving money and getting it online quickly.

Employ a combination of free or inexpensive resources available on the Web to build a low-cost site that\'s easy to maintain. The ingredients for this Recipe are:

1. A domain parked at a registrar that allows you to forward requests for the domain to another URL

2. A small amount of free hosting space provided by your internet service provider, school, employer, or other reliable web server operator

3. One or more blogs hosted by Blogger (or another free blogging service)

4. A free Flickr account for storing and sharing images you want to display on your site

5. A free account for managing links on the site, including its navigation

6. A Google-based site search form

web sites start with a domain name. Expect to pay $5 to $10 for a one-year registration, although you may find a cheaper deal for a domain in one of the newer top-level domains (such as .info or .biz) if you shop around. For this Recipe, I registered the domain at ( When choosing a registrar for the site, make sure you can "park" the domain on their DNS servers for free (or a nominal fee) and forward requests for the domain to another URL. In addition to free parking and forwarding, GoDaddy also lets registrants "mask" the forwarded domain, which means that the browser location window will always display the domain name (, even though the pages themselves will be served from another URL.

Next, you\'ll need to find a small amount of hosting space for the site. I found mine through my internet service providerSBCwho, through a partnership with Yahoo!, gives its customers a free GeoCities account with 15MB of disk space. The GeoCities control panel also has a web-based file manager for uploading and editing web pages stored on the account. In my GoDaddy control panel, I set to forward to Because I also instructed GoDaddy to mask the domain, visitors to the site will never see the GeoCities address.
A free Blogger account solves the content management problem. With its user-friendly web-based writing and editing interface, Blogger\'s blogging tools circumvent the need for your less computer-savvy site contributors to set up an FTP client and understand the process of uploading files to the web server. Blogger also offers a variety of design templates for displaying your blog at an address on their server (i.e., But for this site, you will self-syndicate an RSS feed from your blog and display it on a page that you upload just once to your free hosting space.
Self-syndication will be the key to adding navigation and images to the site, and free accounts with and Flickr will provide the tools for doing so. As darlings of the Web 2.0 movement, Flickr and are leading the way in opening the web to new ways of managing images and links on the web. The tagging features of both servicesdubbed folksonomy for their grass-roots inversion of traditional top-down categorization, or taxonomy, of online resourcesenable novel and inspiring ways of communal publishing and sharing with the web.

At the most basic level, is an online bookmark storage service. With it, you can ditch the bookmark list that your browser saves on your PC\'s hard drive and have access to your favorite sites from any browser on any computer that you use. You also can define your own system for categorizing your bookmarks with one or more tags that you assign to each bookmark you add to your account. Flickr works in a similar way, but with images. A free Flickr account provides 20 MB of image-upload storage each month, as well as tools for tagging individual images, generating code for displaying them on another web site, uploading images automatically from your cell phone\'s camera, and posting the images with a short description to a blog hosted by another service (including Blogger).

Best of all for your fast, cheap, and under control site, both and Flickr generate RSS feeds for each tag that you define. So in my account I defined two tags for the links I want to display on the site: "sitenav" for the internal links and "sitelinks" for other web sites that I want to link to from Then, I plugged in the self-syndication code for the two tag feeds into the pages where I want those links to appear: "sitenav" in the sidebar of every page and "sitelinks" on my Links page.


Info source: Web site cookbook

May 04, 2019 at 04:11 PM

Meeting Some Differences between British and American English

Informer : Wegen

Many words differ between American and British English. George Bernard
Shaw said: ‘England and America are two countries divided by a common language.’ He was partially correct, particularly with reference to some vocabulary and some different uses of tenses. For example, British English often
uses the present perfect tense to describe a recently completed action, while
American English uses the past simple. Imagine that you’ve just finished breakfast. A British English speaker would ask ‘Have you finished breakfast yet?’. An American English speaker, on the other hand, is more likely to ask
‘Did you finish breakfast yet?’. 

Info source: Learning English as foreign language

May 04, 2019 at 03:28 PM

Writing Strings That Include Quotes or Special Characters in MySQL

Informer : Wegen

You want to write a quoted string, but it contains quote characters or other special characters, and MySQL rejects it.

4.2.2 Solution
Learn the syntax rules that govern the interpretation of strings in queries.

4.2.3 Discussion
To write a string in a SQL statement, surround it with quote characters:

mysql> SELECT \'hello, world\';
| hello, world |
| hello, world |
But sometimes you need to write a string that includes a quote character, and if you just put the quote into the string as is, a syntax error results:

mysql> SELECT \'I\'m asleep\';
ERROR 1064 at line 1: You have an error in your SQL syntax near \'asleep\'\'
at line 1
You can deal with this several ways:

MySQL, unlike some SQL engines, allows you to quote strings with either single quotes or double quotes, so you can enclose a string containing single quotes within double quotes:

mysql> SELECT "I\'m asleep";
| I\'m asleep |
| I\'m asleep |
This works in reverse, too; a string containing double quotes can be enclosed within single quotes:

mysql> SELECT \'He said, "Boo!"\';
| He said, "Boo!" |
| He said, "Boo!" |
To include a quote character within a string that is quoted by the same kind of quote, either double the quote or precede it with a backslash. When MySQL reads the query string, it will strip off the extra quote or the backslash:

mysql> SELECT \'I\'\'m asleep\', \'I\\\'m wide awake\';
| I\'m asleep | I\'m wide awake |
| I\'m asleep | I\'m wide awake |
1 row in set (0.00 sec)
mysql> SELECT "He said, ""Boo!""", "And I said, \\"Yikes!\\"";
| He said, "Boo!" | And I said, "Yikes!" |
| He said, "Boo!" | And I said, "Yikes!" |
A backslash turns off the special meaning of the following character. (It causes a temporary escape from normal string processing rules, so sequences such as \\\' and \\" are called escape sequences.) This means that backslash itself is special, so to write a literal backslash within a string, you must double it:

mysql> SELECT \'Install MySQL in C:\\\\mysql on Windows\';
| Install MySQL in C:\\mysql on Windows |
| Install MySQL in C:\\mysql on Windows |
Other escape sequences recognized by MySQL are \\b (backspace), \\n (newline, also called linefeed), \\r (carriage return), \\t (tab), and \\0 (ASCII NUL).  

Info source: O\'Reilly MySQL cookbook

May 04, 2019 at 03:16 PM

The Meaning of localhost in MySQL

Informer : Wegen

One of the parameters you specify when connecting to a MySQL server is the host where the server is running. Most programs treat the hostname localhost and the IP address as synonymous. Under Unix, MySQL programs behave differently; by convention, they treat the hostname localhost specially and attempt to connect to the server using a Unix domain socket file. To force a TCP/IP connection to the local host, use the IP address rather than the hostname localhost. (Under Windows, localhost and are treated the same, because Windows doesn\'t have Unix domain sockets.)

The default port is 3306 for TCP/IP connections. The pathname for the Unix domain socket varies, although it\'s often /tmp/mysql.sock. The recipes indicate how to specify the socket file pathname or TCP/IP port number explicitly if you don\'t want to use the default.  

Info source: O\'Reilly MySQL cookbook

May 04, 2019 at 03:07 PM

Using mysql as a Calculator

Informer : Wegen

You need a quick way to evaluate an expression.

1.32.2 Solution
Use mysql as a calculator. MySQL doesn\'t require every SELECT statement to refer to a table, so you can select the results of arbitrary expressions.

SELECT statements typically refer to some table or tables from which you\'re retrieving rows. However, in MySQL, SELECT need not reference any table at all, which means that you can use the mysql program as a calculator for evaluating an expression:

mysql> SELECT (17 + 23) / SQRT(64);
| (17 + 23) / SQRT(64) |
| 5.00000000 |
This is also useful for checking how a comparison works. For example, to determine whether or not string comparisons are case sensitive, try the following query:

mysql> SELECT \'ABC\' = \'abc\';
| \'ABC\' = \'abc\' |
| 1 |
The result of this comparison is 1 (meaning "true"; in general, nonzero values are true). This tells you that string comparisons are not case sensitive by default. Expressions that evaluate to false return zero:

mysql> SELECT \'ABC\' = \'abcd\';
| \'ABC\' = \'abcd\' |
| 0 |
If the value of an expression cannot be determined, the result is NULL:

mysql> SELECT 1/0;
| 1/0 |
| NULL |
SQL variables may be used to store the results of intermediate calculations. The following statements use variables this way to compute the total cost of a hotel bill:

mysql> SET @daily_room_charge = 100.00;
mysql> SET @num_of_nights = 3;
mysql> SET @tax_percent = 8;
mysql> SET @total_room_charge = @daily_room_charge * @num_of_nights;
mysql> SET @tax = (@total_room_charge * @tax_percent) / 100;
mysql> SET @total = @total_room_charge + @tax;
mysql> SELECT @total;
| @total |
| 324 |

Info source: O\'Reilly MySQL cookbook

May 02, 2019 at 02:47 PM

Turning Your Website Skills into Cash

Informer : Wegen

1. Becoming a Paid Website Designer

2. Putting Ads on Your Site
. Although a few doom-and-gloom types insist web advertising is dead, online ads are indeed alive and well and making people money. You may as well be one of them.
. If you want to attract more traffic to your site, choose a banner exchange network; if you have a reasonable amount of traffic, sign up with an ad network to start making money on your site right away.
. To get the most out of Google AdSense, place your ads in high-focus areas, avoid banners, and make your ad units resemble the rest of your page content.

3. Working With Affiliate Programs
. An affiliate program is a CPA-based advertising program where you partner with a selling site by setting up product links and receiving a percentage of each sale.
* cost-per-action (CPA) is where you get paid each time someone clicks an ad and performs some action, such as purchasing a product, filling in a form, registering with the site, and so on.
. Before signing up with an affiliate program, do some homework. Study commission rates and learn how commissions are generated, when you get paid, and what restrictions the program insists upon.
. Choose a program that fits in with the content of your site, encourage visitors to buy the products, and make your store an attractive place to shop.

4. Selling Stuff on Your Site 

Info source: The complete idiot\'s guide to creating a website

May 02, 2019 at 02:03 PM

Common error codes

Informer : Wegen

Code Meaning
200 OK, the request has succeeded
401 Unauthorized, the request requires authorization
403 Forbidden, the request was refused
404 Not found
500 Internal server error 

Info source: O\'Reilly website cookbook

May 02, 2019 at 01:55 PM

Monitoring Web Server Activity

Informer : Wegen

You want to see programs your web server is running and user requests for web pages.

Use command-line tools to get a real-time snapshot of web server activity:

1. tail
Returns the last part of a file, such as most recent connection entries from the web server logfile
2. grep
Searches for a pattern in a file, such as specific filenames or error codes from the web server logfile

3. ps
Reports on the status of web server processes


Almost any decent web hosting account will record connections to your web site in log files that you can view and process. A good hosting provider may even help you automate the task of purging the connection records or log rolling so the files do not consume your account\'s disk quota, and give you access to web site statistics software, such as Analog or Urchin, that will generate easy-to-read reports about activity on your web site.

If you\'re serious about your web site, then you should take advantage of the tools available to you and review web site traffic reports often to understand how visitors get to your site, what\'s popular, and what\'s working (or not working).

The access and error logs that provide the raw material for traffic reports are constantly updated. Traffic reports themselves, on the other hand, are usually generated less frequently daily, or even weekly, in some cases. A situation may arise when you can\'t wait for the next traffic report to be created. You need to get an up-to-the-minute picture of the who, what, and how many of your web site\'s current activity. Here are some command-line tools you can use to take your web site\'s pulse.

Using tail to track web site requests in real time:

First, you\'ll need to find your Apache access and error log files. They are usually saved in a separate logs directory and have names like access_log, access.log, or apache.access_log. The error log should be in the same directory with the access log, so once you\'ve found the logs, Telnet into your web server and switch to the logfiles directory.

Now you can watch connections to your web site as they\'re handled by Apache with the Unix utility tail. Assuming your access log is named access_log, type this command at your Telnet prompt:

tail -f access_log
Your shell window should be filled with several lines, like this: - - [14/May/2005:12:49:26 -0500] "GET
/swgr/index.php HTTP/1.1" 200 29070
"" "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)" - - [14/May/2005:12:49:30 -0500] "GET
/case_studies/cs01.html HTTP/1.0" 200 19604 "-" "Mozilla/4.0
(compatible; MSIE 5.01; Windows NT; .NET CLR 1.1.4322)" - - [14/May/2005:12:49:33 -0500] "GET
/clients/index.html HTTP/1.1" 301 255 "-" "Mozilla/4.0 (compatible;
MSIE 6.0; Windows NT 5.1; SV1)"

Each line indicates the IP number, file requested, and status of each unique connection, or hit, to your web site. The -f flag on the command tells tail to show the last 10 lines in the access log, and to echo new lines to the shell window as they are appended to the file. See for yourself: open a browser window and, with your shell window still visible, hit a page on your web site. Your request should be duly noted by tail. 

Info source: O\'Reilly website cookbook

Apr 30, 2019 at 05:13 PM

Managing and Protecting a Domain Name

Informer : Wegen Fantu

You need to protect the investment you made in a domain name for your web site.

Learn how the domain registration system works and keep your domain from being neglected or stolen by:

1. Knowing the expiration date

2. Keeping contact information up to date

3. Enabling domain security features

4. Choosing a strong domain management password

5. Registering your domain name as a trademark

6. Reading every email your registrar sends to you carefully

7. Consolidating multiple domains

8. Registering domain name variants

9. Using a domain-name monitoring service

10. Planning ahead if you move your domain to another host

11. Setting up a third-party, backup DNS service

Here are some important techniques for domain management that can prevent the inadvertent loss of your domain name:

1. Keep track of the expiration date.
Put the date on your calendar and keep a print-out of your whois record listing the administrative, billing, technical contacts, and expiration date in your files. Use the buddy system: make sure at least one other person with an interest in protecting the domain knows the expiration date and whois record information. Choose a registration term that won\'t exceed the institutional memory of the domain name owners. Although many registrars offer domain-name periods of up to 10 years, I prefer to keep mine for two or three years. That way, I get a chance every so often to review the value of the domain and even choose a new registrar if I want and I was never very good at that "Where will you be in five years?" interview question either.

2. Make sure the contact information is up to date.

The whois listing should have your correct contact data and list the proper owner: either the administrative contact, billing contact, or both. Make sure that you give your registrar, as well as your hosting company, an email address that\'s not in case there are problems with your domain name or account that make your email inoperable.

3. Enable any and all security features that your registrar offers.

A new ICANN domain transfer policy went into effect in the second half of 2004 that cut the time between a transfer request and its taking place to as little as five days. Basically, it allows anyone to request a domain transfer and the registrar to authorize the transfer if the current owner does not object. When this policy went into effect, one pithy online forum poster quipped that it spelled the end of week-long, internet-free vacations for web builders everywhere. You can prevent this form of hijacking by enabling a registration lock on your domain. Only unlocked domains can fall victim to the new quick transfer procedure, and only the owner of the domain can unlock it. Other security features vary among registrars, so familiarize yourself with those that are available on your domain and use them to protect it.

4. Choose a complex, hard-to-guess domain management password.

Don\'t email this password to anyone. Most good registrars offer web-based tools for managing your domain, so you\'ll need to create a secure password for accessing your account. Choose one that contains at least eight characters, including both upper and lowercase letters and one numeral. Don\'t base it on a real word, or any other bit of personal information that could be guessed by other means, such as your birthday, address, or phone number. If you need to give the password to a colleague or web designer, do not send it by email. Email can be intercepted and read by someone you can\'t trust en route to its intended recipient. When sharing sensitive passwords, deliver them in person, over the phone, or by fax, provided the receiving fax machine is in a trusted location. If you forget your password and your registrar emails it to you, log in and change the password immediately. Many registrars use a better method of resetting a forgotten password and requiring the domain owner to verify the change by logging in to their account. In either case, don\'t forget to make a note of your new password.

5. Register your domain name as a trademark, if possible.

If your web site address identifies a distinctive product or service that your business provides, then you might consider applying for trademark protection through the U.S. Patent and Trademark Office, and other national trademark offices as necessary. Trademark protection can be a potential weapon on your side, should a dispute over your domain name arise. Bear in mind, however, that the most insidious domain hijackers may re-register your domain in a country that does not have the same high regard for U.S. trademarks as you do. In that case, prepare for a long, costly and usually fruitless effort to reclaim your stolen domain. For more resources on handling domain disputes, refer to the organizations listed under "See Also" at the end of this section.

6. Read every email your registrar sends you carefully and skeptically.

ICANN now requires registrars to contact domain name owners annually to verify contact information. Unscrupulous domain name speculators also will try to contact you with an email that appears to come from your registrar, in an attempt to trick you into providing information to them that they can use to hijack your domain. If you\'re unsure about any communication you get regarding your domain, call your registrar or report the fraudulent email to them immediately.

7. Consolidate multiple domains with one registrar and common expiration date.

It\'s tempting to shop around for the best deal when registering a new domain name, but before you know it you\'ve got nearly as many domain management accounts with various registrars as you have domains under your control. The potential to lose one or more of your domains is an order of magnitude greater in this situation. Find the registrar with the best balance of features, prices and management tools that meet your needs, and stick with that registrar. Move domains at other registrars over to your preferred registrar when they\'re up for renewal. The little bit of extra money you will spend will be worth it for peace of mind.

8. Register as many variants of your domain as your budget will allow.

Often, the appearance of a hijacked domain can be more likely and more damaging than the hijacking itself. Take the case of a hypothetical nonprofit that registers only the dot-org (.org) variation of its name. A group with opposing views or just a penchant for mischief can set up a web site using the dot-com (.com) domain, leaving visitors who don\'t know any better confused about which site truly speaks for the organization.

9. Use a domain name monitoring service such as SnapNames or NameProtect.

SnapNames and NameProtect allow you to get alerts about potentially unwanted changes to domains you own and registration opportunities for domains you don\'t own but want to own.

10. Plan ahead if you move your domain to another host.

One of the services your web-hosting company will provide for you is DNS on its domain name servers. The DNS system functions as the address book of the world wide web, matching up the internet protocol (IP) numbers by which network traffic gets routed with alphabetical domain names that are easier for humans to remember. Just as previous residents at your home address may periodically get letters in your mailbox, the DNS system of web site addresses does not get updated instantaneously when you move your site and domain to a new web hosting service. That\'s because when you move your site, the domain name remains the same but the IP number associated with it changes, and propagation of the new IP number associated with your domain name to the thousands of DNS servers around the world takes anywhere from 24 to 72 hours.

When moving your site, follow these steps in order or risk your site disappearing from the web temporarily while information about your move spreads throughout the DNS system:

1. Set up your new hosting account.
2. Copy all your web site files to the new account when you have confirmation that the account is set up (usually within 24 hours).
3. Place a hidden tag of comment text that distinguishes it from the file on the old web server on your home page file saved on the new web server, like this:

<!-- new host -->
4. Preview how the site will look by connecting to it with your web browser using the IP number of the new web server or a preview URL provided by the hosting company (e.g.,
5. Notify your domain registrar that you want to change the DNS server information for your domain to those maintained by your new hosting company when you\'re satisfied that the site on the new host\'s servers looks and behaves like the site on the current host\'s servers. (They should give the IP numbers and/or hostnames of their DNS servers when you sign up.)

Usually, you can update your DNS information via your registrar\'s web-based control panel for your account. At this point, the waiting period for the DNS change begins, so any changes you make to your site during this period must be made to files on both the old and new hosting account. I prefer to pull the trigger on DNS changes on a Friday, let the propagation occur over the weekend, and then check the site on Monday. Viewing source and finding the hidden tag confirms that the propagation is almost, if not entirely, done. By the middle of the week, you can cancel your old hosting account.

11. Consider setting up a third-party, backup DNS service.

This allows you to respond to web site outages quickly. If your hosting provider\'s DNS server goes down, then your web site will be down, too. For a nominal fee, you can set up a backup DNS listing through a company such as Ultra DNS to avoid this situation. 

Info source: O\'Reilly website cookbook

Apr 30, 2019 at 04:48 PM

Registering a Domain Name

Informer : Wegen Fantu

Registering a Domain Name
You need to register a new domain name for your web site.

Choose the right domain name and registrar for your web site after weighing factors such as budget and goals for organizational identity.

Choosing a new domain name for a web site can often seem like shopping on the last day of an end-of-season sale at a popular clothing store. The best choices were long ago snapped up by the early shoppers. Like a picked-over pile of extra-small beige golf shirts, the remaining choices may not be a perfect fit for your planned web site.

Check the registrar of your choice to see if the domain name you want is already registered. Assuming for a minute that you will not be able to acquire your first choice (or second, or even third), here are some guidelines to consider when registering a brand new domain name:

Consider using your company or organization\'s short branding message or marketing slogan as your domain name. For example, if Wal-Mart\'s deep pockets and legions of lawyers were not able to wrest ownership of from a hypothetical cyber squatter, they might consider an acceptable alternative.

Try to come up with an action-oriented phrase or common aphorism that dovetails with the mission of your web site, and build your web site around that domain. For example, a site that promotes good health through good diet might register

Try adding your city, state, or other local identifier to your already-taken first or second choice to find an acceptable alternative that you can claim for your own, such as or

Avoid using hyphens and long acronyms in your domain name. You might be tempted to register an alternative domain name by tweaking your already-taken first choice with hyphens between key words, or by reducing your business name to an alphabet-soup acronym of unrelated letters. Don\'t do it. A fair share of your potential site visitors will trip over these grammatical stumbling blocks, leaving your web site lost in cyberspace. For example, works; does not.

Consider registering a domain name from the ever-growing list of new top-level domains (TLDs)(see Table 1-1).

Top-level domains: past, present, and future
May be registered by anyone; operated by VeriSign Global Registry. Available since 1995.
May be registered by anyone; operated by VeriSign Global Registry. Available since 1995.
May be registered by anyone; operated by Public Interest Registry. Available since 1995.
Reserved for U.S. educational institutions, such as universities or high schools. Operated by EDUCAUSE. Available since 1995.
Reserved for U.S. government use since 1995.
Reserved for U.S. military use since 1995.
Other sponsored top-level domains (sTLDs)
Sponsored by the Societe Internationale de Telecommunications Aeronautiques SC (SITA) and restricted to organizations within the air transport industry. Available since 2001.
Operated by NeuLevel, a joint venture between NeuStar, a Virginia-based telecommunications company, and Melbourne IT, an Australian domain name registration service. Must be used by businesses for commercial purposes. Available since 2001.
Sponsored by Dot Cooperation LLC and the National Cooperative Business Association, based in Washington, D.C. It is restricted to cooperative organizations. Available since 2001.
Operated by Afilias Limited, a consortium of 19 major domain name registrars including VeriSign,, and Tucows. Anyone may register a .info domain name. Available since 2001.
Registrants must be an intergovernmental organization. Operated by the Internet Assigned Numbers Authority (IANA). Available since 1998.
Sponsored and administered by the Museum Domain Management Association, a nonprofit organization founded by the International Counsel of Museums and the J. Paul Getty Trust. Restricted to accredited museums worldwide. Available since 2001.
Offered to individuals for personal web sites and email addresses; operated by Global Name Registry. Available since 2001.
Marketed to professionals, such as accountants, doctors, lawyers, and engineers. Operated exclusively by RegistryPro. Available since 2002.
Proposed by DotAsia Organisation Ltd. in early 2004.
Approved by ICANN in September 2005, but it is not for feline aficionados. From the applicant\'s web site: "Why do we want .cat? Because the Catalan language and culture are a community that wants to be identified with its own domain on the internet." Who\'s next? Klingons?
Sponsored by the Society for Human Resource Management (SHRM); approved by ICANN in late 2004.
Proposed by the Spamhaus Project and others as an antidote to spam.
Sponsored by Mobi JV, a consortium of Microsoft, Nokia, and Vodafone and other heavy-weight multinational corporations. Geared toward web sites to be viewed on mobile devices, such as PDAs and cell phones. Approved by ICANN in July 2005.
Sponsored by the Switzerland-based Universal Postal Union; approved by ICANN in late 2004.
ICANN approved Telnic\'s application to run a TLO for managing corporate and individual contact information in July 2005.
Sponsored by the Travel Partnership Corporation; approved by ICANN in late 2004.

In August 2005, the Bush administration expressed its opposition to the creation of a new TLD specifically for the porn industry.
Originally for use by the eastern European Republic of Moldova; now marketed to physicians.
Administered by the .tv Corporation, a subsidiary of VeriSign. This TLD hit the free market in 2000 thanks to the South Pacific island nation of Tuvalu.
Commonly used for city, county, and state web sites in the United States, now sold for commercial use to web sites with domains in every other TLD.
Proposed to ICANN by EURid for use by businesses and individuals in the European Union.
With your domain name chosen, it\'s time to claim it as your own by registering it. To make sense of the often complex and overlapping roles of domain name registrars and web site hosting providers, consider this great analogy (related on numerous sites on the Web) that recasts the process as one that should be familiar to car owners everywhere.

Imagine for a minute that your web site is an automobilesay, a red Lexus RX 330and its domain name is a personalized license plate. To get a license plate for your Lexus, you register it with your local department of motor vehicles; to get a domain name for your web site, you must register it with an accredited domain name registrar. The Internet Corporation for Assigned Names and Numbers (ICANN) keeps a list of accredited registrars on its web site ( If the registrar you want to use is not on the list, they are likely a reseller of an approved registrar\'s services. Many web hosting companies (more on them later) offer domain name registration in this way.

Most Lexus owners, it\'s safe to assume, keep their cars in a garage, be it semi-detached in a suburban subdivision or underground in spot C219. After you have registered your domain name, you have to find a place to keep it. Web hosting companies typically provide domain name service (DNS) and disk space on a web server where web site designers "park" their web sites.

But where the rubber meets the road, so to speak, is where you as the web designer draw the line between registration and web hosting. Manyif not mostregistrars can host your site, and a growing number of hosting companies can register your domain name when you sign up for one of their hosting plans. But few Lexus owners would grant the clerks at the DMV the dual role of parking attendant for one of their most valuable assets (their car). For your domain name and web site, you would be wise to abide by the same separation-of-powers principle, choosing one company to handle your domain registration and a different one to do the hosting.

Why? Here are some gotchas to beware of and avoid when choosing a registrar and host for your domain name and web site:

. Hosting companies that offer to register your domain name have been known to list themselves as the owner of your domain name. Although this practice is less common than it once was, and by no means widespread, clearing up this administrative wrinkle in your DNS record can be a real headache if or when the time comes to relocate your web site to a new hosting provider. Bottom line: if you choose to register and host with the same company, read the fine print in your service agreement.

.Registrars that offer no-cost, or low-cost, registration in exchange for you also choosing them as your hosting provider may be doing so in hopes of collecting high fees when your domain comes up for renewal. Expect to pay $10 to $35 for a one-year registration. Bottom line: assume that you\'re getting what you pay for and make sure you know who\'s responsible for what.

Info source: Web site cookbook

Apr 30, 2019 at 04:25 PM

Matching a Valid Email Address, Regular expression, PHP

Informer : Wegen Fantu

You want to check if an email address is valid.

This is a popular question and everyone has a different answer, depending on their definition of valid. If valid means a mailbox belonging to a legitimate user at an existing hostname, the real answer is that you can\'t do it correctly, so don\'t even bother. However, sometimes a regular expression can help weed out some simple typos and obvious bogus attempts. That said, our favorite pattern that doesn\'t require maintenance is:

If the IMAP extension is enabled, you can also use imap_rfc822_parse_adrlist( ) :

$parsed = imap_rfc822_parse_adrlist($email_address, $default_host)
if (\'INVALID_ADDRESS\' == $parsed[\'mailbox\']) {
// bad address
Ironically, because this function is so RFC-compliant, it may not give the results you expect.  

Info source: O\'Reilly PHP Cookbook

Apr 24, 2019 at 05:05 PM

Computer Security

Informer : Wegen Fantu

Computer Security, techniques developed to safeguard information and information systems stored on computers. Potential threats include the destruction of computer hardware and software and the loss, modification, theft, unauthorized use, observation, or disclosure of computer data.
Computers and the information they contain are often considered confidential systems because their use is typically restricted to a limited number of users. This confidentiality can be compromised in a variety of ways. For example, computers and computer data can be harmed by people who spread computer viruses and worms. A computer virus is a set of computer program instructions that attaches itself to programs in other computers. The viruses are often parts of documents that are transmitted as attachments to e-mail messages. A worm is similar to a virus but is a self-contained program that transports itself from one computer to another through networks. Thousands of viruses and worms exist and can quickly contaminate millions of computers.
People who intentionally create viruses are computer experts often known as hackers. Hackers also violate confidentiality by observing computer monitor screens and by impersonating authorized users of computers in order to gain access to the users’ computers. They invade computer databases to steal the identities of other people by obtaining private, identifying information about them. Hackers also engage in software piracy and deface Web sites on the Internet. For example, they may insert malicious or unwanted messages on a Web site, or alter graphics on the site. They gain access to Web sites by impersonating Web site managers.
Malicious hackers are increasingly developing powerful software crime tools such as automatic computer virus generators, Internet eavesdropping sniffers, password guessers, vulnerability testers, and computer service saturators. For example, an Internet eavesdropping sniffer intercepts Internet messages sent to other computers. A password guesser tries millions of combinations of characters in an effort to guess a computer’s password. Vulnerability testers look for software weaknesses. These crime tools are also valuable security tools used for testing the security of computers and networks.
An increasingly common hacker tool that has gained widespread public attention is the computer service saturator, used in denial-of-service attacks, which can shut down a selected or targeted computer on the Internet by bombarding the computer with more requests than it can handle. This tool first searches for vulnerable computers on the Internet where it can install its own software program. Once installed, the compromised computers act like “zombies” sending usage requests to the target computer. If thousands of computers become infected with the software, then all would be sending usage requests to the target computer, overwhelming its ability to handle the requests for service.
A variety of simple techniques can help prevent computer crimes, such as protecting computer screens from observation, keeping printed information and computers in locked facilities, backing up copies of data files and software, and clearing desktops of sensitive information and materials. Increasingly, however, more sophisticated methods are needed to prevent computer crimes. These include using encryption techniques, establishing software usage permissions, mandating passwords, and installing firewalls and intrusion detection systems. In addition, controls within application systems and disaster recovery plans are also necessary.

Storing backup copies of software and data and having backup computer and communication capabilities are important basic safeguards because the data can then be restored if it was altered or destroyed by a computer crime or accident. Computer data should be backed up frequently and should be stored nearby in secure locations in case of damage at the primary site. Transporting sensitive data to storage locations should also be done securely.

Another technique to protect confidential information is encryption. Computer users can scramble information to prevent unauthorized users from accessing it. Authorized users can unscramble the information when needed by using a secret code called a key. Without the key the scrambled information would be impossible or very difficult to unscramble. A more complex form of encryption uses two keys, called the public key and the private key, and a system of double encryption. Each participant possesses a secret, private key and a public key that is known to potential recipients. Both keys are used to encrypt, and matching keys are used to decrypt the message. However, the advantage over the single-key method lies with the private keys, which are never shared and so cannot be intercepted. The public key verifies that the sender is the one who transmitted it. The keys are modified periodically, further hampering unauthorized unscrambling and making the encrypted information more difficult to decipher.

Another technique to help prevent abuse and misuse of computer data is to limit the use of computers and data files to approved persons. Security software can verify the identity of computer users and limit their privileges to use, view, and alter files. The software also securely records their actions to establish accountability. Military organizations give access rights to classified, confidential, secret, or top-secret information according to the corresponding security clearance level of the user. Other types of organizations also classify information and specify different degrees of protection.

Passwords are confidential sequences of characters that allow approved persons to make use of specified computers, software, or information. To be effective, passwords must be difficult to guess and should not be found in dictionaries. Effective passwords contain a variety of characters and symbols that are not part of the alphabet. To thwart imposters, computer systems usually limit the number of attempts and restrict the time it takes to enter the correct password.
A more secure method is to require possession and use of tamper-resistant plastic cards with microprocessor chips, known as “smart cards,” which contain a stored password that automatically changes after each use. When a user logs on, the computer reads the card\'s password, as well as another password entered by the user, and matches these two respectively to an identical card password generated by the computer and the user\'s password stored in the computer in encrypted form. Use of passwords and \'smart cards\' is beginning to be reinforced by biometrics, identification methods that use unique personal characteristics, such as fingerprints, retinal patterns, facial characteristics, or voice recordings.

Computers connected to communication networks, such as the Internet, are particularly vulnerable to electronic attack because so many people have access to them. These computers can be protected by using firewall computers or software placed between the networked computers and the network. The firewall examines, filters, and reports on all information passing through the network to ensure its appropriateness. These functions help prevent saturation of input capabilities that otherwise might deny usage to legitimate users, and they ensure that information received from an outside source is expected and does not contain computer viruses.

Security software called intrusion detection systems may be used in computers to detect unusual and suspicious activity and, in some cases, stop a variety of harmful actions by authorized or unauthorized persons. Abuse and misuse of sensitive system and application programs and data such as password, inventory, financial, engineering, and personnel files can be detected by these systems.

The most serious threats to the integrity and authenticity of computer information come from those who have been entrusted with usage privileges and yet commit computer fraud. For example, authorized persons may secretly transfer money in financial networks, alter credit histories, sabotage information, or commit bill payment or payroll fraud. Modifying, removing, or misrepresenting existing data threatens the integrity and authenticity of computer information. For example, omitting sections of a bad credit history so that only the good credit history remains violates the integrity of the document. Entering false data to complete a fraudulent transfer or withdrawal of money violates the authenticity of banking information. These crimes can be prevented by using a variety of techniques. One such technique is checksumming. Checksumming sums the numerically coded word contents of a file before and after it is used. If the sums are different, then the file has been altered. Other techniques include authenticating the sources of messages, confirming transactions with those who initiate them, segregating and limiting job assignments to make it necessary for more than one person to be involved in committing a crime, and limiting the amount of money that can be transferred through a computer.

Organizations and businesses that rely on computers need to institute disaster recovery plans that are periodically tested and upgraded. This is because computers and storage components such as diskettes or hard disks are easy to damage. A computer\'s memory can be erased or flooding, fire, or other forms of destruction can damage the computer’s hardware. Computers, computer data, and components should be installed in safe and locked facilities.  

Info source: Microsoft student

Apr 24, 2019 at 04:40 PM

Virus-like compute programs

Informer : Wegen

There are other harmful computer programs that can be part of a virus but are not considered viruses because they do not have the ability to replicate. These programs fall into three categories: Trojan horses, logic bombs, and deliberately harmful or malicious software programs that run within a Web browser, an application program such as Internet Explorer and Netscape that displays Web sites.
A Trojan horse is a program that pretends to be something else. A Trojan horse may appear to be something interesting and harmless, such as a game, but when it runs it may have harmful effects. The term comes from the classic Greek story of the Trojan horse found in Homer’s Iliad.
A logic bomb infects a computer’s memory, but unlike a virus, it does not replicate itself. A logic bomb delivers its instructions when it is triggered by a specific condition, such as when a particular date or time is reached or when a combination of letters is typed on a keyboard. A logic bomb has the ability to erase a hard drive or delete certain files.
Malicious software programs that run within a Web browser often appear in Java applets and ActiveX controls. Although these applets and controls improve the usefulness of Web sites, they also increase a vandal’s ability to interfere with unprotected systems. Because those controls and applets require that certain components be downloaded to a user’s personal computer (PC), activating an applet or control might actually download malicious code. 

Info source: Microsoft ® Encarta

Apr 24, 2019 at 04:33 PM


Informer : Wegen Fantu

A. Preparation and Prevention
Computer users can prepare for a viral infection by creating backups of legitimate original software and data files regularly so that the computer system can be restored if necessary. Viral infection can be prevented by obtaining software from legitimate sources or by using a quarantined computer—that is, a computer not connected to any network—to test new software. Plus, users should regularly install operating system (OS) patches, software updates that mend the sort of flaws, or holes, in the OS often exploited by viruses. Patches can be downloaded from the Web site of the operating system’s developer. However, the best prevention may be the installation of current and well-designed antiviral software. Such software can prevent a viral infection and thereby help stop its spread.

B. Virus Detection
Several types of antiviral software can be used to detect the presence of a virus. Scanning software can recognize the characteristics of a virus\'s computer code and look for these characteristics in the computer\'s files. Because new viruses must be analyzed as they appear, scanning software must be updated periodically to be effective. Other scanners search for common features of viral programs and are usually less reliable. Most antiviral software uses both on-demand and on-access scanners. On-demand scanners are launched only when the user activates them. On-access scanners, on the other hand, are constantly monitoring the computer for viruses but are always in the background and are not visible to the user. The on-access scanners are seen as the proactive part of an antivirus package and the on-demand scanners are seen as reactive. On-demand scanners usually detect a virus only after the infection has occurred and that is why they are considered reactive.
Antivirus software is usually sold as packages containing many different software programs that are independent of one another and perform different functions. When installed or packaged together, antiviral packages provide complete protection against viruses. Within most antiviral packages, several methods are used to detect viruses. Checksumming, for example, uses mathematical calculations to compare the state of executable programs before and after they are run. If the checksum has not changed, then the system is uninfected. Checksumming software can detect an infection only after it has occurred, however. As this technology is dated and some viruses can evade it, checksumming is rarely used today.
Most antivirus packages also use heuristics (problem-solving by trial and error) to detect new viruses. This technology observes a program’s behavior and evaluates how closely it resembles a virus. It relies on experience with previous viruses to predict the likelihood that a suspicious file is an as-yet unidentified or unclassified new virus.
Other types of antiviral software include monitoring software and integrity-shell software. Monitoring software is different from scanning software. It detects illegal or potentially damaging viral activities such as overwriting computer files or reformatting the computer\'s hard drive. Integrity-shell software establishes layers through which any command to run a program must pass. Checksumming is performed automatically within the integrity shell, and infected programs, if detected, are not allowed to run.

C. Containment and Recovery
Once a viral infection has been detected, it can be contained by immediately isolating computers on networks, halting the exchange of files, and using only write-protected disks. In order for a computer system to recover from a viral infection, the virus must first be eliminated. Some antivirus software attempts to remove detected viruses, but sometimes with unsatisfactory results. More reliable results are obtained by turning off the infected computer; restarting it from a write-protected floppy disk; deleting infected files and replacing them with legitimate files from backup disks; and erasing any viruses on the boot sector.


Info source: Microsoft ® Encarta

Apr 19, 2019 at 01:53 PM

Interview Template, Informational Interview

Informer : Wegen Fantu

Request an informational interview with a potential employer:

[Your Name]
[Street Address]
[City, ST ZIP Code]
April 19, 2019

[Recipient Name]
[Company Name]
[Street Address]
[City, ST ZIP Code]

Dear [Recipient Name]:

I am currently researching positions in the field of [industry or job field] and [Name of Person Referring You] suggested that you would be an excellent source of information. I would like to learn more about the types of jobs available in this field and the skills required for them.
As you will see from the enclosed resume, my education and work experience are in [job field]. I hope to transfer the skills that I’ve acquired over the years to a job in [industry or job field].
I hope that you can find 30 minutes to meet with me before the end of the month. I will contact you the week of [date] to set up an appointment. If you have questions, please contact me by phone at [phone number] or by e-mail at [e-mail address]. I appreciate your time in considering my request.


[Your Name]


Info source: Microsoft student Microsoft ® Encarta

Apr 17, 2019 at 11:45 AM

Emergency numbers

Informer : Wegen

Ethio telecom: 994
ፌደራል ፖሊስ ዋና መስሪያ ቤት
ስልክ ቁጥር፡+251115512744
Emergency: 911
Addis Ababa police +251.11 1559122
Traffic Police +251.11 5528222
Emergency: 945.
Ethiopian Electric Power Corporation (EEPCo)
South Addis Abeba 0114-431478
North Addis Abeba 0112-595657
West Addis Abeba 0113-490585
East Addis Abeba 0116-465144
Central Addis Ababa 0111-262105
Red Cross society: 907
Ambulance - 907;
Fire Accident Emergency Number: 902
Tel: 011-663-0373903 

Info source: Different sources


Online E-books, Textbooks and related materials.