ANTIVIRUS(PC SOFTWARE)

Antivirus (or anti-virus) software is used to prevent, detect, and remove malware, including computer viruses, worms, and trojan horses. Such programs may also prevent and remove adware, spyware, and other forms of malware.

A variety of strategies are typically employed. Signature-based detection involves searching for known malicious patterns in executable code. However, it is possible for a user to be infected with new malware in which no signature exists yet. To counter such so-called zero-day threats, heuristics can be used. One type of heuristic approach, generic signatures, can identify new viruses or variants of existing viruses by looking for known malicious code (or slight variations of such code) in files. Some antivirus software can also predict what a file will do if opened/run by emulating it in a sandbox and analyzing what it does to see if it performs any malicious actions. If it does, this could mean the file is malicious.

However, no matter how useful antivirus software is, it can sometimes have drawbacks. Antivirus software can degrade computer performance if it is not designed efficiently. Inexperienced users may have trouble understanding the prompts and decisions that antivirus software presents them with. An incorrect decision may lead to a security breach. If the antivirus software employs heuristic detection (of any kind), success depends on achieving the right balance between false positives and false negatives. False positives can be as destructive as false negatives. In one case, a faulty virus signature issued by Symantec mistakenly removed essential operating system files, leaving thousands of PCs unable to boot.[1] Finally, antivirus software generally runs at the highly trusted kernel level of the operating system, creating a potential avenue of attack.[2]

In addition to the drawbacks mentioned above, the effectiveness of antivirus software has also been researched and debated. One study found that the detection success of major antivirus software dropped over a one-year period.[3].

INTERNET

The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private and public, academic, business, and government networks of local to global scope that are linked by a broad array of electronic and optical networking technologies. The Internet carries a vast array of informationresources and services, most notably the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to supportelectronic mail.

Most traditional communications media, such as telephone and television services, are reshaped or redefined using the technologies of the Internet, giving rise to services such asVoice over Internet Protocol (VoIP) and IPTV. Newspaper publishing has been reshaped into Web sites, blogging, and web feeds. The Internet has enabled or accelerated the creation of new forms of human interactions through instant messaging,Internet forums, and social networking sites.

The origins of the Internet reach back to the 1960s when the United States funded research projects of its military agencies to build robust, fault-tolerant and distributed computer networks. This research and a period of civilian funding of a new U.S. backbone by the National Science Foundation spawned worldwide participation in the development of new networking technologies and led to thecommercialization of an international network in the mid 1990s, and resulted in the following popularization of countless applications in virtually every aspect of modern human life. As of 2009, an estimated quarter of Earth's population uses the services of the Internet.

The Internet has no centralized governance in either technological implementation or policies for access and usage; each constituent network sets its own standards. Only the overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address space and the Domain Name System, are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN). The technical underpinning and standardization of the core protocols (IPv4 and IPv6) is an activity of the Internet Engineering Task Force (IETF), a non-profit organization of loosely-affiliated international participants that anyone may associate with by contributing technical expertise.

WEBSITE

A website (also spelled web site) is a collection of related web pages, images, videos or other digital assets that are addressed with a common domain name or IP address in an Internet Protocol-based network. A web site is hosted on at least one web server, accessible via a network such as the Internetor a private local area network.

A web page is a document, typically written in plain text interspersed with formatting instructions ofHypertext Markup Language (HTML, XHTML). A web page may incorporate elements from other websites with suitable markup anchors.

Web pages are accessed and transported with the Hypertext Transfer Protocol (HTTP), which may optionally employ encryption (HTTP Secure, HTTPS) to provide security and privacy for the user of the web page content. The user's application, often a web browser, renders the page content according to its HTML markup instructions onto a display terminal.

All publicly accessible websites collectively constitute the World Wide Web.

The pages of a website can usually be accessed from a simple Uniform Resource Locator (URL) called the homepage. The URLs of the pages organize them into a hierarchy, although hyperlinking between them conveys the reader's perceived site structure and guides the reader's navigation of the site.

Some websites require a subscription to access some or all of their content. Examples of subscription sites include many business sites, parts of many news sites, academic journal sites, gaming sites,message boards, web-based e-mail, services, social networking websites, and sites providing real-timestock market data.

computer softwares

Computer software, or just software is a general term primarily used for digitally stored data such ascomputer programs and other kinds of information read and written by computers. Today, this includes data that has not traditionally been associated with computers, such as film, tapes and records.^[1] The term was coined in order to contrast to the old term hardware (meaning physical devices); in contrast to hardware, software is intangible, meaning it "cannot be touched".^[2] . Software is also sometimes used in a more narrow sense, meaning application software only.

COMPUTER NETWORKING

A computer network is a group of computers that are connected to each other for the purpose of communication. Networks may be classified according to a wide variety of characteristics. This article provides a general overview of types and categories and also presents the basic components of a network.

data tape

HP SDLT storage media is ideally suited for data centre and departmental backups where capacity, performance and cost are critical. SDLT technology offers up to 160 GB of storage capacity and a 16MB/sec sustained data transfer rate (native mode).2nd generation Super DLT II 600GB Data Cartridge offers high capacity and low cost per GB for customers with prior investments in DLT backup technology. Super DLTtape II cartridges support DLTSage for improved media and drive diagnostics. High-performance: up to 32MB/sec compressed transfer rate Comprehensive: read-backwards compatible with DLTtape High-capacity: supports capacities up to 320GB Reliable: combines the best of proven optical and magnetic technologies to offer users improvements in capacity and performance HP SDLT cleaning cartridges: provide 20 cleans With 600GB capacity and 72MB/sec transfer rate, HP SDLT II 600GB Data Cartridges offer high capacity and low cost per GB for customers with prior investments in DLT backup technology. Super DLTtape II uses a new Super PET (S-PET) base film enabling an overall thickness reduction of 10%. This results in a longer tape with more capacity versus a Super DLTtape I cartridge. Optical servo guide information is coded on the rear of the media, increasing the number of recording tracks on the data-bearing media surface. This enables higher capacity tape cartridges like Super DLT II.

VGA CABLE

A VGA connector (also RGB connector, D-sub15, mini sub D15, and mini D15 connector), is a three-row 15-pin DE-15 connector, of which there are four versions: (i) the original VGA15 pinout connector, (ii) DDC2 pinouts, (iii) the older, less flexible DE-9 connector, and (iv) the Mini-VGA used for laptop computers.

The 15-pin VGA connector is common to most video cards, computer monitors, and high definition television sets that support VGA-connector devices. It usually is known as an “HD-15” (High Density 15) or “DE-15”, distinguishing it from connectors of like form factor, but with only 2 rows of pins. Occasionally, this connector is incorrectly referred to as a “DB-15” or as an “HDB-15”.^{[citation needed]} VGA connectors and cables are used solely to carry analog componentRGBHV (red - green - blue - horizontal sync - vertical sync) video signals, a Display data channel (DDC2) digital clock, and data. When device size is a spatial constraint (i.e. laptop computers), a mini-VGA port occasionally is in place of the full-sized VGA connector.