Apache
Apache is the most popular Web serversoftware. It enables a computer to host one or more websites that can be accessed over the Internet using a Web browser. The first version of Apache was released in 1995 by the Apache Group. In 1999, the Apache Group became the Apache Software Foundation, a non-profit organization that currently maintains the development of the Apache Web server software.
Apache's popularity in the Web hosting market is largely because it is open sourceand free to use. Therefore, Web hosting companies can offer Apache-based Web hosting solutions at minimal costs. Other server software, such as Windows Server, requires a commercial license. Apache also supports multiple platforms, including Linux, Windows, and Macintosh operating systems. Since many Linux distributions are also open-source, the Linux/Apache combination has become the most popular Web hosting configuration.
Apache can host static websites, as well as dynamic websites that use server-side scripting languages, such as PHP, Python, or Perl. Support for these and other languages is implemented through modules, or installation packages that are added to the standard Apache installation. Apache also supports other modules, which offer advanced security options, file management tools, and other features. Most Apache installations include a URL rewriting module called "mod_rewrite," which has become a common way for webmasters to create custom URLs.
While the Apache Web server software is commonly referred to as just "Apache," it is technically called "Apache HTTP Server," since the software serves webpages over theHTTP protocol. When Apache is running, its process name is "httpd," which is short for "HTTP daemon."
Applet
An applet is a small application designed to run within another application. While the term "applet" is sometimes used to describe small programs included with a computer's operating system, it usually refers to Java applets, or small applications written in the Java programming language.
Unlike ordinary applications, Java applets cannot be run directly by the operating system. Instead, they must run within the Java Runtime Environment (JRE), or within another program that includes a Java plug-in. If there is no JRE installed, Java applets will not run. Fortunately, Java is freely available for Windows, Mac, and Linux systems, which means you can easily download and install the appropriate JRE for your system. Since Java applets run within the JRE and are not executed by the operating system, they are crossplatform, meaning a single applet can run on Windows, Mac, and Linux systems.
While applets can serve as basic desktop applications, they have limited access to system resources and therefore are not ideal for complex programs. However, their small size and crossplatform nature make them suitable for Web-based applications. Examples of applets designed to run in web browsers include calculators, drawing programs, animations, and video games. Web-based applets can run in any browser on any operating system and long as the Java plug-in is installed.
During the early years of the Web, Java applets provided a way for webmasters to add interactive features that were not possible with basic HTML. However, in recent years, applets have been slowly replaced by newer technologies such as jQuery and HTML 5. Some browsers, like Google Chrome, no longer support the <applet> tag, and others, like Apple Safari, do not even enable Java by default. Since web developers cannot fully rely on Java support from web browsers, applets are no longer a common way to provide interactive content on the Web.
Archie
Archie is a program that allows you to search for files available on one or more FTP servers. It was commonly used in the early 1990s, but has been replaced by standard web-based search engines and peer-to-peer (P2P) file sharing services.
In the early days of the Internet, large files were often available only through FTP servers. In order to download a specific file, users would have to navigate to the appropriate directory and then find the correct file before downloading it. This made it difficult for people to locate files unless they knew exactly where they were stored on the server. Archie made it possible for users to actually search FTP servers rather than browsing through all the directories.
While Archie is rarely used today, some websites still offer an Archie search feature. You can often identify an Archie search engine by a URL that begins with "archie" rather than "www." Most Archie search engines allow you to search for filenames based on either substrings or exact matches. You can also specify if a search should be case sensitive or not. Additionally, you can use boolean operators such as AND and OR to search for multiple filenames at once.
ASP
ASP has two different meanings in the IT world: 1) Application Service Provider, and 2) Active Server Page.
1) Application Service Provider
An Application Service Provider is a company or organization that provides software applications to customers over the Internet. These Internet-based applications are also known as "software as a service" (SaaS) and are often made available on a subscription basis. This means ASP clients often pay a monthly fee to use the software, rather than purchasing a traditional software license. Some SaaS applications can be accessed via a web browser, while others operate over a proprietary secure port.
2) Active Server Page
An Active Server Page, commonly called an "ASP page," is a webpage that may contain scripts as well as standard HTML. The scripts are processed by an ASP interpreter on the web server each time the page is accessed by a visitor. Since the content of an ASP page can be generated on-the-fly, ASP pages are commonly used for creating dynamic websites.
ASP is similar to other scripting platforms, like PHP and JSP, but supports multiple programming languages. While the default ASP language is VBScript, ASP pages can include other programming languages as well, such as C# and JavaScript. However, alternative languages must be defined before the script code using the following declaration:
<%@ Page Language="C#"%>
ASP pages are part of the ASP.NET web application framework developed by Microsoft. Therefore, ASP pages are most often found on Windows-based web servers that run Microsoft Internet Information Services, or IIS. You can tell if you are accessing an ASP page in your browser if the URL has an ".asp" or ".aspx" suffix.
File extensions: .ASP, .ASPX
ASP.NET
ASP.NET is a set of Web development tools offered by Microsoft. Programs like Visual Studio .NET and Visual Web Developer allow Web developers to create dynamic websites using a visual interface. Of course, programmers can write their own code and scripts and incorporate it into ASP.NET websites as well. Though it often seen as a successor to Microsoft's ASP programming technology, ASP.NET also supports Visual Basic.NET, JScript .NET and open-source languages like Python and Perl.
ASP.NET is built on the .NET framework, which provides an application program interface (API) for software programmers. The .NET development tools can be used to create applications for both the Windows operating system and the Web. Programs like Visual Studio .NET provide a visual interface for developers to create their applications, which makes .NET a reasonable choice for designing Web-based interfaces as well.
In order for an ASP.NET website to function correctly, it must be published to a Web server that supports ASP.NET applications. Microsoft's Internet Information Services (IIS) Web server is by far the most common platform for ASP.NET websites. While there are some open-source options available for Linux-based systems, these alternatives often provide less than full support for ASP.NET applications.
ATM
Stands for "Asynchronous Transfer Mode." Most people know of ATMs as automated teller machines -- those friendly boxes that allow you to withdraw cash from your bank or credit account while charging you a ridiculous surcharge for the service. In the computer world, however, ATM has a different meaning. Asynchronous Transfer Mode is a networking technology that transfers data in packets or cells of a fixed size.
ATM uses 53-byte cells (5 bytes for the address header and 48 bytes for the data). These extremely small cells can be processed through an ATM switch (not an automated teller machine) fast enough to maintain data transfer speeds of over 600 mbps. The technology was designed for the high-speed transmission of all forms of media from basic graphics to full-motion video. Because the cells are so small, ATM equipment can transmit large amounts of data over a single connection while ensuring that no single transmission takes up all the bandwidth. It also allows Internet Service Providers (ISPs) to assign limited bandwidth to each customer. While this may seem like a downside for the customer, it actually improves the efficiency of the ISP's Internet connection, causing the overall speed of the connection to be faster for everybody.
Attachment
An attachment, or email attachment, is a file sent with an email message. It may be an image, video, text document, or any other type of file.
Most email clients and webmail systems allow you to send and receive attachments. To send an attachment along with your email, you can use the "Attach" command, then browse to the file you want to attach. In some email interfaces, you can simply drag a file into the message window to attach it. When you receive an attachment, most email programs allow you to view the attachment in place or save it to your local storage device.
While modern email programs make it easy to send and receive attachments, the original email system (SMTP) was actually not designed to handle binary files. Therefore, attachments must be encoded as text in order to be transferred with an email message. The most common encoding type is MIME (Multi-Purpose Internet Mail Extensions). While MIME encoding makes it possible to send messages with emails, it typically increases the file size of the attachment about 30%. That's why when you attach a file to an email message, the file size of the attachment appears larger than the original file.
You can attach multiple files to a single email message. However, the maximum size of the combined attachments is limited by the sending and receiving mail servers. In other words, the size of the attachment(s) after being encoded cannot be larger than the limit of either the outgoing or incoming mail server. In the early days of email, attachments were limited to one megabyte (1 MB). Today, many mail servers allow attachments larger than 20 MB. However, to protect against viruses and malware, many mail servers will not accept executable file types, such as .EXE or .PIF files. If you need to send an executable file to someone, you can compress the file as a .ZIP archive before attaching it to the email message.
NOTE: Even a large amount of text takes up a small amount of space compared to most binary files. Therefore, attaching a document to an email may increase the size substantially. For example, a typical email may only require one kilobyte (1 KB) of disk space. Attaching a single 1 MB file will make the message 1,000 times larger. Therefore, it is best to share large files using another method like FTP or DropBox. Additionally, if you have almost reached your email quota on your mail server, you can free up a lot of space by deleting old attachments.
AUP
Stands for "Acceptable Use Policy." An AUP is list of rules you must follow in order to use a website or Internet service. It is similar to a software license agreement (SLA), but is used specifically for Internet services.
Most well-known, high traffic websites include an AUP, which may also be called Terms of Service (TOS) or Terms of Use (TOU). You can often find a link to the to the website's AUP in the footer of the home page. Many web services, such as cloud applications require you to agree to an AUP in order to use the online service. ISPs often provide an AUP with each account, which states specific guidelines you must follow.
The specifics of an AUP vary depending on the service offered. Even website AUPs may differ greatly based on the purpose of the website and the website's content. However, most AUPs include a list of general dos and don'ts while using the service, such as the following:
Do not violate any federal or state laws.
Do not violate the rights of others.
Do not distribute viruses or other malware.
Do not try to gain access to an unauthorized area or account.
Respect others' copyrights and intellectual property.
Familiarize yourself with the usage guidelines and report violations.
An AUP serves as an agreement between the user and the company offering the online service. Some rules are basic netiquette, while others may have legal ramifications. If you fail to comply with a policy in a AUP, the company has the right to suspend or terminate your account or take legal action if necessary. Therefore, it is wise to familiarize yourself with the AUPs of the Internet services you use.
Autoresponder
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 important to reply to messages even after the autroresponder has sent a esponse. After all, most people like to communicate with other people rather than computers.
Avatar
Generally speaking, an avatar is the embodiment of a person or idea. However, in the computer world, an avatar specifically refers to a character that represents an online user. Avatars are commonly used in multiplayer gaming, online communities, and Web forums.
Online multiplayer role-playing games (MMORPGs) such as World of Warcraft and EverQuest allow users to create custom characters. These characters serve as the players' avatars. For example, a World of Warcraft player may choose a Paladin with blue armor as his avatar. As the player progresses in the game, his character may gain items and experience, which allows the avatar to evolve over time.
Avatars are also used in online communities, such as Second Life and The Sims Online. These avatars can be custom-designed to create a truly unique appearance for each player. Once a user has created an avatar, he or she becomes part of an online community filled with other users' avatars. Players can interact with other avatars and talk to them using text or voice chat. It's no surprise that "Second Life" refers to a virtual life that players live through their avatars.
Finally, avatars may also seen in Web forums. Online discussion boards typically require users to register and provide information about themselves. Many give users the option to select an image file that represents the user's persona. This image, combined with a made-up username, serves as a person's avatar. For example, a user may select a picture of a Pac-Man and choose the name "pac32" for his avatar. This avatar typically appears next to each posting the user contributes in an online forum.
Regardless of the application, avatars allow people to represent themselves online in whatever way they want. They may be considered alter-egos, since users can customize characters that are completely different than their actual personas. Of course, what's the point of having a "second life" if it's the same as reality?
3G
3G is a collection of third generation cellular data technologies. The first generation (1G) was introduced in 1982, while the second generation of cellular data technologies (2G) became standardized in the early 1990s. 3G technologies were introduced as early as 2001, but did not gain widespread use until 2007.
In order to be labeled "3G," a cellular data transfer standard must meet a set of specifications defined by the International Telecommunications Union, known as IMT-2000. For example, all 3G standards must provide a peak data transfer rate of at least 2 Mbps. Most 3G standards, however, provide much faster transfer rates of up to 14.4 Mbps.
While many cell phone companies market phones with "3G technology," there is no single 3G standard. Rather, different companies use their own technologies to achieve similar data transfer rates. For example, AT&T uses a 3G technology based on GSM, while Verizon uses a technology based on CDMA. Additionally, cell phone networks outside the United States use different IMT-2000 compliant standards to achieve 3G data transfer speeds.
3G precedes 4G, the fourth generation of cellular data technologies.
404 Error
A 404 error is a common website error message that indicates a webpage cannot be found. It may be produced when a user clicks an outdated (or "broken") link or when a URL is typed incorrectly in a Web browser's address field. Some websites display custom 404 error pages, which may look similar to other pages on the site. Other websites simply display the Web server's default error message text, which typically begins with "Not Found." Regardless of the appearance, a 404 error means the server is up and running, but the webpage or path to the webpage is not valid.
So why call it a "404 error" instead of simply a "Missing Webpage Error?" The reason is that 404 is an error code produced by the Web server when it cannot find a webpage. This error code is recognized by search engines, which helps prevent search engine crawlers from indexing bad URLs. 404 errors can also be read by Web scripts and website monitoring tools, which can help webmasters locate and fix broken links.
Other common Web server codes are 200, which means a webpage has been found, and 301, which indicates a file has moved to a new location. Like 404 errors, these status messages are not seen directly by users, but they are used by search engines and website monitoring software.
4G
4G is a collection of fourth generation cellular data technologies. It succeeds 3G and is also called "IMT-Advanced," or "International Mobile Telecommunications Advanced." 4G was made available as early as 2005 in South Korea under the name WiMAX and was rolled out in several European countries over the next few years. It became available in the United States in 2009, with Sprint being the first carrier to offer a 4G cellular network.
All 4G standards must conform to a set of specifications created by the International Telecommunications Union. For example, all 4G technologies are required to provide peak data transfer rates of at least 100 Mbps. While actual download and upload speeds may vary based on signal strength and wireless interference, 4G data transfer rates can actually surpass those of cable modem and DSL connections.
Like 3G, there is no single 4G standard. Instead, different cellular providers use different technologies that conform to the 4G requirements. For example, WiMAX is a popular 4G technology used in Asia and Eastern Europe, while LTE (Long Term Evolution) is more popular in Scandinavia and the United states.
Address Bar
An address bar is a text field near the top of a Web browser window that displays the URL of the current webpage. The URL, or web address, reflects the address of the current page and automatically changes whenever you visit a new webpage. Therefore, you can always check the location of the webpage you are currently viewing with the browser's address bar.
While the URL in the address bar updates automatically when you visit a new page, you can also manually enter a web address. Therefore, if you know the URL of a website or specific page you want to visit, you can type the URL in the address bar and press Enter to open the location in your browser.
NOTE: The URL typically begins with "http://", but most browsers will automatically add the HTTP prefix to the beginning of the address if you don't type it in.
The appearance of the address bar varies slightly between browsers, but most browsers display a small 16x16 pixel icon directly to the left of the URL. This icon is called a "favicon" and provides a visual identifier for the current website. Some browsers also display an RSS feed button on the right side of the address bar when you visit a website that offers RSS feeds. In the Safari web browser, the address bar also doubles as a progress bar when pages are loading and includes a refresh button on the right side. Firefox includes a favorites icon on the right side of the address bar that lets you add or edit a bookmark for the current page.
The address bar is sometimes also called an "address field." However, it should not be confused with a browser toolbar, such as the Google or Yahoo! Toolbar. These toolbars typically appear underneath the address bar and may include a search field and several icons.
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