Computer Tutorial Hub

This is a server that all computers on the local network have to go through before accessing information on the Internet.  By using a proxy server, an organization can improve the network performance and filter what users connected to the network can access. While your Web browser might save recently viewed items on your computer, a proxy server stores in cache everything accessed from the network.  That means if Arun views a news story at cnn.com at 12:00 and Anitha views the same page at 12:03, she'll most likely get the page straight from the proxy server's cache. Though this means super-fast access to Web pages, it also means users might not be seeing the latest update of each Web page. The other main purpose a proxy server is to filter what is allowed into the network. While HTTP, FTP, and Secure protocols can all be filtered by a proxy server, HTTP is the most common.  The proxy server can limit what Web sites users on the network can access....

 Canvio Connect is  a portable USB 3.0 hard drive that enables personal cloud storage. The Canvio Connect comes preinstalled with software that turns the  p ortable drive into an online file server when it is plugged into a Windows or Mac computer.  As long as the Canvio Connect is connected to an Internet-enabled PC that is powered on, users will have complete access to files, photos, music and movies from any device. The Canvio Connect serves as a portable hard drive but can also be used to back up images and other files from mobile devices.  Toshiba has announced 10-GB of free cloud storage available to Canvio Connect users (via the Pogoplus service). Canvio Connect was announced  on April 30, 2013 by Toshiba's Digital Products Division (DPD), a division of Toshiba America Information Systems, Inc.

A torrent is a file sent via the BitTorrent protocol . It can be just about any type of file, such as a movie, song, game, or application.  During the transmission, the file is incomplete and therefore is referred to as a torrent. Torrent download that have been paused or stopped cannot be opened as regular files, since they do not contain all the necessary data. However, they can often be resumed using a BitTorrent client, as long as the file is available from another server. Torrents are different from regular downloads in that they are usually downloaded from more than one server at a time. The BitTorrent protocol uses multiple computers to transfer a single file, thereby reducing the bandwidth required by each server. When a torrent download is started, the BitTorrent system locates multiple computers with the file and downloads different parts of the file from each computer. Likewise, when sending a torrent, the server may send the file to mu...

A cron job is a script that runs on a web server to perform maintenance tasks on regularly scheduled intervals. web servers need to do weekly, daily, or even hourly, maintenance tasks. This helps them stay tartar free. Cron jobs can do all sort of things. They can backup files or databases, they can clean up data, they can send emails, they can transfer data from one place to another, they can update information from external sources. One of the most common cron jobs is a script that regularly logs onto the Internet and downloads all your email. The only thing that all cron jobs share is that they are scripts that are run automatically on a set schedule.

A technique for  mystifying  the true origin of packets on an IP network in order to preserve privacy and shield a user's online activities from monitoring by government, corporate or other entities.  Onion routing hides online activity by sending p ackets  through a distributed network  of randomly selected  proxy servers  before they are delivered to their final destination. Onion -routed packets are securely encrypted , with the packets unwrapped by a symmetric encryption  key at each server, peeling off the layers of the message a server at a time.  Onion routing was originally developed by the U.S. Navy, and the Navy has financed the development of a second-generation onion routing project known as Tor .

A phrase used to describe a half-smartphone and half-tablet mobile device (a phone/tablet hybrid).  A phablet is a small pocket-sized mobile device that is a bit larger than the size of an average smartphone, with a touch screen ranging in size from 5 inches (e.g. the Sony Xperia Z) to 6.1 inches (e.g. the Huawei Ascend Mate device).  While larger than a smartphone, the phablet is much smaller than most tablets and can be held and used in one hand. Phablets typically use 3G or 4G networks for cellular calls and are Wi-Fi-enabled devices.

A form of DoS attack known as a degradation -of-service attack, as opposed to a denial -of-service attack. Unlike a regular zombie that paralyzes a system by inundating it with a steady stream of attack traffic, the pulsing zombie attacks with irregular small bursts of attack traffic from multiple sources on a single target over an extended period of time. Pulsing zombie attacks are more difficult to detect and trace because since they are slow and gradual they do not immediately appear as malicious.

Abbreviated WSoD, the White Screen of Death or simply "White Death" refers to an error or issue with an operating system that causes the computer or device to stop working and display only a white screen. The White Screen of Death most often refers to an Apple iPod or iPhone that has locked up due to the device being severely dropped, a hardware component failing, or an attempted operating system or application upgrade that fails to successfully update.  iPod, iPad or iPhone users with a WSoD will see either a completely blank white screen or a frozen display that shows only the Apple logo. How to Fix the White Screen of Death As with the more widely known blue screen of death (BSoD) that affects computers running Windows, the white screen of death generally requires a reboot in order to operate properly again. If restarting the device fails to correct the issue, the White Screen of Death might be resolved by trying one or more of the following: hard re...

Trolls are typically thought of as scary creatures that live underneath bridges. While these mythical creatures may only exist in legend, "Internet trolls" are real and cause real problems.  In computing, the term "troll" refers to a person who posts offensive, incendiary, or off topic comments online.  These comments may appear in Web forums, on Facebook walls, after news articles or blog entries, or in online chat rooms. The action of posting obscene or inflammatory comments is often called "trolling."  This activity is highly discouraged and may actually a violation of online community's user agreement. Fortunately, webmasters  and forum moderators typically have the power to remove offensive or off topic posts and even terminate accounts if needed.

  Graymail describes email messages that are generally unwanted, but do not fit the definition of  spam . Unlike spam, graymail includes messages from mailing lists and newsletters that you have legitimately signed up to receive. Over time, these messages can begin to clutter your  inbox  and can easily be mistaken for spam. The term "graymail" was coined by the Microsoft Hotmail team in 2011, when the company introduced new methods of filtering incoming messages. Graymail differs from spam in the following ways: The email is solicited.  You request to receive graymail by opting in, either directly or indirectly. For example, a direct method is subscribing to a mailing list. An indirect method is providing your email address when you register with an e-commerce. The email is legitimate.  Graymail messages are sent by reputable sources who value their relationship with the recipient. The messages usually contain an unsubscribe ...

A file sharing feature from Apple available on mobile devices running the iOS 7 (and later) mobile operation system as well as laptops and desktops running Mac OS X 10.7 Lion and later.  Photos and videos can be shared with AirDrop, as well as notes, URLs, Passbook passes, contact cards, iTunes Radio stations, app listings and more. AirDrop utilizes a combination of Bluetooth 4.0 and Wi-Fi technology when sharing files between devices, with Bluetooth responsible for device discovery and secure connections, and Wi-Fi used for handling the actual transfer of files for faster performance. AirDrop debuted with the release of Mac OS X Lion, and iOS 7 brought the feature to all iPhone 5 models, the iPod touch 5th generation, the iPad 2 and later releases, and the iPad Mini.  It's important to note though that at this time AirDrop cannot be used across the Mac OS X and iOS 7 platforms.

On many blogs including Typepad, Blogger, Live Journal, Moveable Type, and Wordpress, the words "Digg This" may appear below a blog post as a hyperlink which readers can click to submit the post to the Digg Web site.

A collection of malware developed to create a sophisticated network of botnets that can distribute spam, redirect Web traffic and infect users' computers with malware, all while keeping the location of the cyber criminals perpetrating the attacks a secret. Operation Windigo is believed to have been growing behind the scenes for the past three years. It gained public attention in March 2014, when software security firm ESET revealed it was responsible for compromising more than 25,000 Linux servers.  At one point during this time the Windigo network was sending 35 million daily spam messages and redirecting more than 500,000 web visitors to exploits kits each day, according to ESET. Operation Windigo primarily relies on two Linux backdoors, Linux/Ebury and Linux/Cdorked, to steal login credentials, compromise Web servers and redirect traffic. Notable victims of Operation Windigo have included cPanel, a popular web hosting control panel platform, and ker...

The app that lets you chat WITHOUT an internet or phone connection: FireChat uses hidden iOS feature to relay messages The iOS 7 feature is called Multipeer Connectivity Framework (MCF) It creates what's called a wireless mesh, or peer-to-peer, network Instead of sending messages using a mobile signal, the free app creates its own network where each mobile on it becomes a 'node' This means people in close proximity can message other nodes Messages are also sent over long distance by relaying data from one node to another anonymously The FireChat app was developed by the crowdsourced firm Open Garden. When a user opens the app, they can pick a screen name to start sending messages. Within the app there are 'chatrooms' with 'Everyone' and 'Nearby' options. The former will search for all users, while the latter option applies to people within Bluetooth and Wi-Fi range who are also using the app. This is particularly useful wh...

A Web ring is a way of interlinking related Web sites so that people can visit many similar Web sites by just following the "Web ring" link on each page.  Most Web rings allow people to browse backwards or forwards through the sites in   the ring, or choose to visit individual sites from a list.  The rings are typically run from a main site which uses a Web scripting application to select random sites and keep the ring up to date. This includes getting rid of outdated pages and links, and adding new ones.  There are tens of thousands of Web rings for topics like football, cars, celebrities, computers, TV shows, etc. You can tell if a Web page is part of Web ring if on the bottom of the page it has some huge, obtrusive, off-color, button linking to other sites in the ring.

An autoresponder is a program or script on a mail server that automatically replies to e-mails. Though it is run from the mail server, an autoresponder can usually be set up by the user through a Web-based interface.  For example, a company might set up an autoresponder for their support e-mail address to let users know they have received their support requests.  The automated reply might read something like, "Thank you, we have received your message. One of our technicians will attempt to answer your question after he finishes his dart game in the lobby." Individuals may also use autoresponders to let people know when they are away from their computer and won't be able to respond to any e-mails for awhile. For example, you might set up an autoresponder for your personal e-mail address to say, "Sorry, I am on vacation in the Bahamas indefinitely. I'll respond to your message whenever I decide to come back." Of course, it is...

Del.icio.us , pronounced simply "delicious," is a community bookmarking website in which users can save Web pages they find and share them with other users.  Because users' bookmarks are made public and viewable by other users, other people often bookmark Web pages that they find within other users' bookmarks.  Del.icio.us keeps track of how many people bookmark each site and posts the most popular websites on its home page. Common Web pages bookmarked by Del.icio.us users include news stories, online learning resources, and tech support pages. Since other users add useful pages to their bookmarks, the best Web pages eventually rise to the top of the popularity chain. The result is a collection of Web pages that are helpful and worthwhile visiting. Users can either browse or search the database of bookmarks on Del.icio.us . When a user saves a bookmark, he or she can add a description and tags (keywords) that are pertinent to the Web page. ...

The term "firewall" originally referred to fireproof walls that were designed to prevent the spread of fire from one room or building to the next.  They were typically made of brick, steel, or another type of inflammable material that would effectively limit the spread of the fire.  In the IT world, firewalls do not involve any fire or pyrotechnics, but they serve a similar purpose.  A computer firewall limits the data that can pass through it and protects a networked server or client machine from damage by unauthorized users. Firewalls can be either hardware or software-based.  A router is a good example of a hardware device that has a built-in firewall.  Most routers can be configured to limit traffic from certain IP addresses or block requests based on other criteria.  Software programs that monitor and restrict external access to a computer or network can also serve as firewalls.   A network firewall only all...

Definition - What does  Short Code  mean? Short codes are special numbers that are shorter than telephone numbers and are mainly used for short message service and MMS. A short code is a shorter  Definition - What does  Short Code  mean? Short codes are special numbers that are shorter than telephone numbers and are mainly used for short message service and MMS. A short code is a shorter number to which an SMS or text message can be sent. Short codes are widely used in automated services. They are considered the fastest and most convenient way for businesses to send and receive short message service. They are mostly used for value-added services. Short codes are also known as short numbers. explaination   Short Code Short codes are most commonly used in marketing campaigns or as a simple way for customers to communicate with companies that serve them. For example, following the earthquake in Haiti in 2010, people were able t...

A spider is a software program that travels the Web (hence the name "spider"), locating and indexing websites for search engines. All the major search engines, such as Google and Yahoo!, use spiders to build and update their indexes. These programs constantly browse the Web, traveling from one hyperlink to another. For example , when a spider visits a website's home page, there may be 30 links on the page. The spider will follow each of the links, adding all the pages it finds to the search engine's index. Of course, the new pages that the spider finds may also have links, which the spider continues to follow. Some of these links may point to pages within the same website (internal links), while others may lead to different sites (external links). The external links will cause the spider to jump to new sites, indexing even more pages. Because of the interwoven nature of website links, spiders often return to websites that have already been...

Many websites that host online communities allow you to create you own personal URL within the website. This custom URL typically serves as the Web address of your profile page and can be shared and bookmarked by other users. Personal URLs are also called purls, personalized URLs, or custom Web addresses.  They are different from personal home pages, which are created and published on a user's own website. Examples of websites that allow you to choose a personal URL include social networking sites like Facebook, photo sharing sites like Flickr, and various Web forums.  Users can choose a custom name, which will then become part of their personal URL. For example, a personal URL on Facebook may be  http://www.facebook.com/ username . The username might be a made up name, such as "pinkbunny77" or your actual name, such as "john.johnson." If you have an account on a website that allows you to select a personal URL, but have not c...

Emoji  are the  ideograms  or  smileys  used in  Japanese  electronic messages and  webpages , the use of which is spreading outside Japan.   Originally meaning  pictograph ,  the word  emoji  literally means "picture" ( e ) + "character" ( moji ) .  The characters are used much like  ASCII   emoticons  or  kaomoj i , but a wider range is provided, and the icons are standardized and built into the handsets.  Some emoji are very specific to Japanese culture, such as  bowing  businessman, a face wearing a  face mask , a white flower used to denote "brilliant homework," or a group of emoji representing popular foods:  ramen  noodles,  dango , on igiri ,  Japanese curry , and  sushi .  The three main Japanese mobile operators,  NTT DoCoMo ,  au , and  SoftBank Mobile  (formerly  Vodafone ), have each defined ...

salami attack n . A series of minor computer crimes—slices of a larger crime—that are difficult to detect and trace. In the salami technique, cyber criminals steal money or resources a bit at a time. The key here is to make the alteration so insignificant that in a single case it would go completely unnoticed.  E.g. a bank employee inserts a program, into the bank's servers, that deducts a small amount of money (say Rs. 5 a month) from the account of every customer. No account holder will probably notice this unauthorized debit, but the cyber criminal will make a sizable amount of money every month.

A framework is a collection of code libraries that are used to accomplish common tasks when building web applications. Think about it as if you were building a house. Your house may be incredibly unique, but it’s still going to share some things in common with your neighbors house: you probably want a bathroom, a foundation, a roof, and maybe even some support beams. A house building framework might provide you with those house building essentials, plus a handful of useful tools, and maybe even some structure that would make it easy to build that awesome, totally unique house that you have planned. Similarly, no matter how unique your web application is, chances are it will share some commonalities with other websites. For example, most web apps require web servers, databases, the application code itself, and some kind of user interface. If a developer set out to build an application without a framework, she would need to write every single feature from scratch. ...

 An Internet tool for locating people on other sites.  Finger can also be used to give access to non-personal information, but the most common use is to see if a person has an account at a particular site.  Finger was one of the first computer network applications. It enabled people to see who else was using the computer system as well as find basic information on that user.  To find information about a specific user, it was necessary to know that person's email address.  For example, in response to the command Finger atstarr@unix.amherst.edu a computer running the Finger program would respond with the following information: Login name: atstarr             In real life: Andrew Starr Office: Kansas City             Home phone:  555-5555 Last login Mon Nov  8 13:22 on tt...

  A three dimensional (3D) animation technology/format creataed by the Macromedia company. Macromedia Director producess Shockwave files, which can be viewed through a Shockwave player, a  browser"plug-in" computer program or other multimedia applications that access the player.   Shockwave can be used to create more sophisticated animations than the Macromedia Flash format. Shockwave uses the .dir  file extension for source files and .dcr extension for Shockwave "movies."  

Ergonomics is the study of how humans interact with manmade objects. The goal of ergonomics is to create an environment that is well-suited to a user's physical needs. While ergonomics is relevant in many areas, it is commonly applied to the workplace environment.  For example, ergonomics is often used to create comfortable w orkstations  for employees. This may involve choosing customized desks and chairs that fit each individual's body type.  I t may also include providing employees with ergonomick eyboards  and wrist rests that provide better typing posture. Keyboards, mice and other devices that are developed using ergonomics are said to have "ergonomic design." This type of design is produced by ergonomics studies that help engineers better understand the way people use devices.   For example, an ergonomic chair may help support your lower back and prevent you from slouching. An ergonomic desk may adjust to the appropriate height...

A mashup describes a web application that combines multiple services into a single application.  For example , a Web forum may contain a mashup that uses Google Maps to display what parts of the world the users are posting from.  Yahoo offers a mashup called Yahoo! Pipes that aggregates RSS feeds into a single page that can be navigated using a graphical interface. The primary purpose of most Web mashups is to consolidate information with an easy-to-use interface. Because the combinations of Web applications are limitless, so are the possibilities of mashups.  Therefore, as mashups continue to evolve, don't be surprised to see them popping up on your favorite websites. After all, we can always use new tools that help make information easier to find! Note: The term "mashup" has several meanings. It was originally used to describe songs that meshed two different styles of music into one song.  For example, ...

Stands for "User Generated Content. " In the early years of the Web, most websites were static, meaning each page had fixed content that did not change unless it was updated by the webmaster.  As the Web evolved, dynamic websites, which generate content from a database, became the norm. Now, in the Web 2.0 era, many websites now include UGC, or content created by visitors. Many different types of websites contain user generated content.   One example is a Web forum , which allows users to discuss topics by posting comments online.   Another example is a wiki , which allows users to directly add and edit website content.  Wikipedia, for instance, contains information written and submitted by thousands of authors around the world.  Social networking websites like Facebook and LinkedIn, are also UGC websites that allow users to create personal profiles and share information with each other.  These websites simply create a platf...