Operating System is..

An operating system (commonly abbreviated OS and O/S) is the infrastructure software component of a computer system; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer. The operating system acts as a host for applications that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware. This relieves application programs from having to manage these details and makes it easier to write applications. Almost all computers, including handheld computers, desktop computers, supercomputers, and even video game consoles, use an operating system of some type. Some of the oldest models may however use an embedded operating system, that may be contained on a compact disk or other data storage device.

Operating systems offer a number of services to application programs and users. Applications access these services through application programming interfaces (APIs) or system calls. By invoking these interfaces, the application can request a service from the operating system, pass parameters, and receive the results of the operation. Users may also interact with the operating system with some kind of software user interface (UI) like typing commands by using command line interface (CLI) or using a graphical user interface (GUI, commonly pronounced “gooey”). For hand-held and desktop computers, the user interface is generally considered part of the operating system. On large multi-user systems like Unix and Unix-like systems, the user interface is generally implemented as an application program that runs outside the operating system. (Whether the user interface should be included as part of the operating system is a point of contention.)

Common contemporary operating systems include Microsoft Windows, Mac OS, Linux, BSD and Solaris. Microsoft Windows has a significant majority of market share in the desktop and notebook computer markets, while servers generally run on Linux or other Unix-like systems. Embedded device markets are split amongst several operating systems.

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What is Web browser ?

A Web browser is a software application which enables a user to display and interact with text, images, videos, music, games and other information typically located on a Web page at a Web site on the World Wide Web or a local area network. Text and images on a Web page can contain hyperlinks to other Web pages at the same or different Web site. Web browsers allow a user to quickly and easily access information provided on many Web pages at many Web sites by traversing these links. Web browsers format HTML information for display, so the appearance of a Web page may differ between browsers.

Web browsers are the most-commonly-used type of HTTP user agent. Although browsers are typically used to access the World Wide Web, they can also be used to access information provided by Web servers in private networks or content in file systems.

The history of the Web browser dates back to late 1980s, when a variety of technologies laid the foundation for the first Web browser, the WorldWideWeb, by Tim Berners-Lee in 1991. That browser brought together a variety of existing and new software and hardware technologies.

Over the following years, Web browsers were introduced by companies like Mozilla, Netscape, Microsoft, Apple, and Opera. More recently, Google entered the browser market.

Some of the Web browsers currently available for personal computers include Internet Explorer, Mozilla Firefox, Safari, Opera, Avant Browser, Konqueror, Lynx, Google Chrome, Flock, Arachne, Epiphany, K-Meleon and AOL Explorer.

Web browsers communicate with Web servers primarily using Hypertext Transfer Protocol (HTTP) to fetch Web pages. HTTP allows Web browsers to submit information to Web servers as well as fetch Web pages from them. The most-commonly-used version of HTTP is HTTP/1.1, which is fully defined in RFC 2616. HTTP/1.1 has its own required standards that Internet Explorer does not fully support, but most other current-generation Web browsers do.

Pages are located by means of a URL (Uniform Resource Locator, RFC 1738), which is treated as an address, beginning with http: for HTTP transmission. Many browsers also support a variety of other URL types and their corresponding protocols, such as gopher: for Gopher (a hierarchical hyperlinking protocol), ftp: for File Transfer Protocol (FTP), rtsp: for Real-time Streaming Protocol (RTSP), and https: for HTTPS (HTTP Secure, which is HTTP augmented by Secure Sockets Layer or Transport Layer Security).

The file format for a Web page is usually HTML (HyperText Markup Language) and is identified in the HTTP protocol using a MIME content type. Most browsers natively support a variety of formats in addition to HTML, such as the JPEG, PNG and GIF image formats, and can be extended to support more through the use of plugins. The combination of HTTP content type and URL protocol specification allows Web-page designers to embed images, animations, video, sound, and streaming media into a Web page, or to make them accessible through the Web page.

Early Web browsers supported only a very simple version of HTML. The rapid development of proprietary Web browsers led to the development of non-standard dialects of HTML, leading to problems with Web interoperability. Modern Web browsers support a combination of standards-based and de facto HTML and XHTML, which should be rendered in the same way by all browsers. No browser fully supports HTML 4.01, XHTML 1.x or CSS 2.1 yet. Many sites are designed using WYSIWYG HTML-generation programs such as Adobe Dreamweaver or Microsoft FrontPage. Microsoft FrontPage often generates non-standard HTML by default, hindering the work of the W3C in promulgating standards, specifically with XHTML and Cascading Style Sheets (CSS), which are used for page layout. Dreamweaver and other more modern Microsoft HTML development tools such as Microsoft Expression Web and Microsoft Visual Studio conform to the W3C standards.

Some of the more popular browsers include additional components to support Usenet news, Internet Relay Chat (IRC), and e-mail. Protocols supported may include Network News Transfer Protocol (NNTP), Simple Mail Transfer Protocol (SMTP), Internet Message Access Protocol (IMAP), and Post Office Protocol (POP). These browsers are often referred to as "Internet suites" or "application suites" rather than merely Web browsers.

Resource : www.en.wikipedia.org

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Google Disputes Physicist's Energy Usage Claim

by Ainsley Jones

Google issued a retort on its Official blog to a Times of London piece where Harvard physicist Alex Wissner-Gross alleges that every two Google searches generates the same amount of carbon dioxide as boiling a kettle of water, about 15g.

According to the Times report, users conduct about 200 million searches a day globally via Google. The article’s authors say the waste comes in the method Google’s search engine operates. A user’s search request is delivered by the server that produces the fastest answer, causing servers thousands of miles apart to compete against one another and use more energy.

Google claims that it has the most energy-efficient data centers in the industry, which minimizes the energy used per Google search and says that its searches are equivalent to only 0.2 grams of carbon dioxide. The company claims on its blog that during the time it takes to conduct a Google search, an individual’s PC uses more energy than does Google in producing the result.

This TechCrunch.com item via The Washington Post attempts to shed a bit of light on the argument. A 500-page book has a carbon footprint of 2,500 grams, compared to the 7.5 or 0.2 grams a single Google search produces. In addition, a person can conduct a Google search in lieu of traveling somewhere to seek out the information. While the author admits Google can probably become more energy efficient, he believes the tone of the Times article to be alarmist.

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Dealing with computer virus

by : y3dips

A computer virus is a computer program that can copy itself and infect a computer without the permission or knowledge of the user. The term "virus" is also commonly but erroneously used to refer to other types of malware, adware and spyware programs that do not have the reproductive ability. I think all of you know about that, so this is some way to avoid the virus infected computer:
1. Use Antivirus that you believe with always update, regardless of any kind is always provided in the update, and automatically switched protection
2. Always scan all external storage media that will be in use, this may be making a bit but if you Autoprotect anti-virus work then the procedure can be missed
3. If you connect directly to the Internet to try to combine with your Antivirus Firewalls, Anti spamming, etc.

If your computer has been infected with the virus, then do :
1. Detection and determine where some of the virus. whether the floppy disks, network, email? etc., if you are connected to the network then it's good you isolate your first computer (either with cable release or disable the connection)
2. Identification and classifying the type of virus that attacks your computer, the following manner:
- Symptoms that arise, for example: the message, the file is missing or corrupt etc.
- Scan with your antivirus, if you are exposed to when running Autoprotectvius in the definition means that you do not have a computer virus this data, try to manually update or to download a virus definitionnya you install. If the virus to block efforts to update then, strived to use other media (computer) with antivirus update.
3. Clean, after you successfully detect it and then try to seek immediate removal or how to destroy the sites that provide information of the virus. This latest update antivirus if you do not succeed destroy it.
4. The worst, if not all of the above is successfully re-format your computer.

resorce: www.echo.or.id

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