Hosting Terms and Definitions

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Address
Unique identifier of a web page. URL (Uniformed Resource Locator) is more frequently used for this purpose.

Apache
Apache is an open-source (source code is freely available and can be shared) HTTP Web server software. According to Netcraft survey, it is currently the most popular web server on the Net. It is usually run on Unix operating system versions like Linux or BSD, but it can also be run on Windows. It is a full-featured server with many powerful add-ons freely available. Apache's major competitor is Microsoft's IIS.

Archive
Archives are large files containing valuable data. Archives are often compressed to save space.

ASP
Active Server Pages. ASP is Microsoft's server-side scripting technology. An Active Server Page has an .asp extension and it mixes HTML and scripting code that can be written in VBScript or JScript. ASP is distributed with Microsoft's IIS web server, so most host using IIS will also offer ASP for dynamic web programming. ASP.NET is the next version of ASP. Other popular server-side scripting languages are Perl, PHP, ColdFusion, TCL, Python, and JSP.

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Backbone
Main high-speed network connection composing the Internet. Backbones are operated by major telecommunications companies like Sprint, MCI, or AT&T.

Bandwidth
Bandwidth is the amount of data that can be transferred over the network in a fixed amount of time. On the Net, it is usually expressed in bits per second (bps) or in higher units like Mbps (millions of bits per second). 28.8 modem can deliver 28,800 bps, a T1 line is about 1.5 Mbps. Newer technology is allowing DSL

Bot
An automated piece of software that can be used in chat rooms or to crawl the web.

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C/C++
Popular programming languages (C++ includes objects) that can be used to create server programs that run after compilation. C and C++ were not designed specifically for web programming, but they can still be useful, especially because mature compilers producing very fast code and large code libraries already exist.

Cable Internet
Cable Internet takes advantage of technologies to provide digital data transmission over the cable television infrastructure. Cable modems are primarily used to deliver broadband Internet access in the form of cable internet, taking advantage of the high bandwidth of a cable television network. They are commonly found in Australia, New Zealand, Canada, Europe, Costa Rica, and the United States. In the USA alone there were 22.5 million cable modem users during the first quarter of 2005, up from 17.4 million in the first quarter of 2004.

Cable Internet connections are as much as 100 times faster than a dial-up Internet connection, sometimes running at an ultra-fast speed of 5 million bits per second (mbps).

Cascading Style Sheets (CSS)
A style-sheet determines how the HTML document is displayed by the browser. The current version of CSS is version 2 (CSS2).

Certificate
Digital ID used for SSL transactions. It includes owner's public key, the name of the owner, the issuer, hostname, and the expiration date.

CGI
Common Gateway Interface. A standard for interfacing web servers with an executable application. A CGI program can be written in any language like Perl or C/C++ and it is often stored in a special directory like /cgi-bin. CGI is often used to process data from HTML forms.

CGI-Bin
A directory on the server where the executable CGI scripts reside.

Clustering
Connecting many computers and making them appear as one machine. This is done to increase reliability and performance. A perfect example is the World Community Grid.

Co-location
Putting a web server in a dedicated facility that provides high-speed Internet connection, security, environment, backup power, and technical support. Unlike the dedicated server, the client controls both hardware and software.

Cobalt RaQ
Server appliance made by Cobalt specifically for hosting companies. Newest RaQs are Linux-based and provide an easy-to-use interface. RaQs have no features that can't be had in a regular Linux box but they offer pre-installed programs and Cobalt's support.

ColdFusion
ColdFusion is an easy to use server-side scripting language developed by Allaire. It comes with ColdFusion Studio, a visual IDE. Other popular server-side scripting languages are ASP. Perl, PHP, TCL, Python, and JSP.

Control Panel
Control panel included in web hosting packages is an online web-based application that allows you to easily manage different aspects of your account. Most control panels will let you upload files, add email accounts, change contact information, set up shopping carts or databases, view usage statistics, etc.

CPU
Central Processing Unit. The most important part of the computer.

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Data transfer
In Web hosting, the total size of files transferred by an account. Sites with a lots of graphics, downloads, or streaming audio or video and a lot of visitors will require plans with more available transfer.

Database
Data in a structured format stored on a web server. Most popular type is a relational database. The most common query (information retrieval) language for relational databases is SQL. Linux-based hosts most commonly include MySQL database and Windows NT-based hosts usually include Access or MS SQL databases.

Dedicated Server
Similar to co-location, except that you lease or rent hardware from a Web host. The main advantage over co-location is easier upgrade and usually better support. Getting a dedicated server or co-locating is necessary for sites that outgrow shared servers because they use a lot of bandwidth and resources or they require total control over software environment.

DNS
Domain Name System. Internet service that maps Internet domains into corresponding IP addresses. DNS database is distributed and replicated among many DNS servers, so when you change your domain's IP address, the changes take a while to propagate and update around the world.

Domain name
Domain name is an easy-to-remember address that can be translated by DNS into server's IP address. Domain names are hierarchical. Domain's suffix indicates which TLD (top level domain) it belongs to, for example .com, .gov, .org, .net, or .jp. Recently ICANN (Internet Corporation for Assigned Names and Numbers) added several new TLDs, like .biz, .pro., and .museum.

DSL Internet
DSL or xDSL, is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop, although in recent years, the term digital subscriber line has been widely adopted as a more marketing-friendly term for ADSL, which is the most popular version of consumer-ready DSL. DSL can be used at the same time and on the same telephone line with regular telephone, as it uses high frequency, while regular telephone uses low frequency.

DSL typically works by dividing the frequencies used in a single phone line into two primary "bands". The ISP data is carried over the high-frequency band (25 kHz and above) whereas the voice is carried over the lower-frequency band (4 kHz and below). The user typically installs a DSL filter on each phone. This filters out the high frequencies from the phone line, so that the phone only sends or receives the lower frequencies (the human voice). The DSL modem and the normal telephone equipment can be used simultaneously on the line without interference from each other.

Typically, the download speed of consumer DSL services ranges from 256 kilobits per second (kbit/s) to 24,000 kbit/s, depending on DSL technology, line conditions and service level implemented. Typically, upload speed is lower than download speed for Asymmetric Digital Subscriber Line (ADSL) and equal to download speed for the rarer Symmetric Digital Subscriber Line (SDSL).

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Firewall
Firewall refers to either software-only or separate software and hardware combination that serves to protect an internal network or a computer from attacks and unauthorized access by sitting between the Internet and the internal network.

FrontPage Extensions
Microsoft's server-side applications that lets users of FrontPage Web site creation tool to incorporate "web-bots" that perform pre-packaged function like full-text Web site searching or adding a hit counter. FrontPage extensions are also available for Unix-based operating systems but some hosts refuse to use them because of potential security holes.

FTP
File Transfer Protocol. The Internet protocol defining how to download and upload files between a client and an FTP server. Popular client FTP programs are CuteFTP and WS_FTP. Major browser also have FTP capability.

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GIF
Graphics Interchange Format. A graphic file format invented by Compuserve. One of the most widely used formats for internet and web. Uses a lossless compression method, thus ensuring that the quality of the image is not lowered.

Gigabyte
1024 Megabytes.

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Hit
In the WWW world "hit" is used to describe a single request made by a web browser. The data transmitted by the web server in response to the request is a text file or a binary file (images, audio, video, executables and other data).

Home Page
Main web page owned by a company, organization or an individual. This is the page that is initially displayed when user makes a request for a particular domain name.

Host
A networked computer dedicated to providing a certain kind of service. Usually refers to a computer that stores the website files and has a web server running on it.

HTML
HyperText Markup Language. It is the language in which web pages are written. It allows the images to be combined with text and offers wide range of formatting capabilities. One of the most important features of HTML is hypertext, that allows web pages to be liked one to each other. HTML relies on tags, which have the following form: Hyperlink. A part of the web page that links to another web page. By clicking on a hyperlink user redirects the browser to another page. The word hyperlink is sometimes shortened to just "link".

HTTP
Hypertext Transfer Protocol is a communications protocol used to transfer or convey information on intranets and the World Wide Web. Its original purpose was to provide a way to publish and retrieve hypertext pages. Development of HTTP was coordinated by the W3C (World Wide Web Consortium) and the IETF (Internet Engineering Task Force), culminating in the publication of a series of RFCs, most notably RFC 2616 (June 1999), which defines HTTP/1.1, the version of HTTP in common use today.

HTTP is a request/response protocol between a client and a server. The client making an HTTP request - such as a web browser, spider, or other end-user tool - is referred to as the user agent. The responding server - which stores or creates resources such as HTML files and images - is called the origin server. In between the user agent and origin server may be several intermediaries, such as proxies, gateways, and tunnels. HTTP is not constrained to using TCP/IP and its supporting layers, although this is its most popular application on the Internet. Indeed HTTP can be "implemented on top of any other protocol on the Internet, or on other networks. HTTP only presumes a reliable transport; any protocol that provides such guarantees can be used."

Typically, an HTTP client initiates a request by establishing a Transmission Control Protocol (TCP) connection to a particular port on a host (port 80 by default; see List of TCP and UDP port numbers). An HTTP server listening on that port waits for the client to send a request message.

Upon receiving the request, the server sends back a status line, such as "HTTP/1.1 200 OK", and a message of its own, the body of which is perhaps the requested file, an error message, or some other information.

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ICANN
The Internet Corporation for Assigned Names and Numbers (ICANN) is the authority that coordinates the assignment of unique identifiers on the Internet, including domain names, Internet Protocol (IP) addresses, and protocol port and parameter numbers. A globally unified namespace (i.e., a system of names in which there is at most one holder for each possible name) is essential for the Internet to function. ICANN is headquartered in Marina del Rey, California, but is overseen by an international board of directors drawn from across the Internet technical, business, academic, and non-commercial communities. The US government continues to have the primary role in approving changes to the root zone file that lies at the heart of the domain name system. Because the Internet is a distributed network comprising many voluntarily interconnected networks, the Internet, as such, has no governing body. ICANN's role in coordinating the assignment of unique identifiers distinguishes it as perhaps the only central coordinating body on the global Internet, but the scope of its authority extends only to the Internet's systems of domain names, IP addresses, protocol ports and parameter numbers.

Image Map
An image displayed on the webpage that has different areas that are hyperlinks. By clicking on different parts of the image browser can be redirected to another webpage, or can display modified version of the current one.

IMAP
Internet Message Access Protocol. A method allowing a client email program to access remote messages stored on a mail server. The protocol includes operations for creating, deleting, and renaming mailboxes, checking for new messages, message parsing, searching, and setting and clearing flags. IMAP was originally developed in 1986 at Stanford.

InterNIC
The organization that handles domain name registrations. See http://www.internic.net.

Internet
The Internet of today is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked web pages and other resources of the World Wide Web (WWW).

In 1973, the U.S. Defense Advanced Research Projects Agency (DARPA) initiated a research program to investigate techniques and technologies for interlinking packet networks of various kinds. The objective was to develop communication protocols which would allow networked computers to communicate transparently across multiple, linked packet networks. This was called the Internetting Project and the system of networks which emerged from the research was known as the "Internet." The system of protocols which was developed over the course of this research effort became known as the TCP/IP Protocol Suite, after the two initial protocols developed: Transmission Control Protocol (TCP) and Internet Protocol (IP).

In 1986, the U.S. National Science Foundation (NSF) initiated the development of the NSFNET which, today, provides a major backbone communication service for the Internet. With its 45 megabit per second facilities, the NSFNET carries on the order of 12 billion packets per month between the networks it links. The National Aeronautics and Space Administration (NASA) and the U.S. Department of Energy contributed additional backbone facilities in the form of the NSINET and ESNET respectively.

Intranet
A part of an organization's network that is private. Only authorized individuals have access to the Intranet. An Intranet is very similar to the Internet in a sense that it offers the same services and uses the same protocols.

IP
Internet Protocol is the main protocol used on the Internet.

IP Address
Internet Protocol Address. A unique number identifying all devices connected to the Internet. This number is usually shown in four groups of numbers from 0 to 255, separated by periods, for example 207.46.230.218.

ISP
An Internet Service Provider (ISP) provides the hardware, and sometimes software, to allow someone to connect with the Internet. Options include dial up (AOL or Earthlink), DSL (Qwest or Verizon), and cable (Comcast or Time-Warner).

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Java
Sun's popular programming language. Java is a platform-independent (at least in theory), crash-protected, object-oriented language that can be used to write applets that run in a browser, servlets that run server-side, or independent programs. Java's syntax is similar to that of C++.

JavaScript
Simple, client-side programming language created by Sun and Netscape. JavaScript can be embedded in HTML pages to create interactive effects and do tasks like validate form data. JavaScript is a separate language from Java. All popular modern browsers support JavaScript. A few hosts support server-side JavaScript.

JPEG
Joint Photographic Experts Group. A image compression format designed for the Internet. Uses lossy compression, meaning that the quality of the image can be lowered.

JSP
Java Server Pages. Extension of Java Servlet technology for combining Java server-side programs and HTML. JSP pages have an extension .jsp.

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Kbps
Kilobits per second. 1Kbps = 1024bps.

Kilobyte
1024 bytes.

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LAN
Local Area Network. A network of devices (computers, printers, hubs) occupying a small area. Usually LANs do not span more than one building. LANs are very fast compared to WANs.

Linux
A free UNIX-like operating system developed by Linus Torvalds. Linux and FreeBSD are very often used by hosting companies as their operating systems.

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MBps
MegaBytes (MB) per second, 1 MB = 1,048,576 bytes.

Mbps
Megabits (Mb) per second, 1Mb = 1,048,576 bits.

Megabyte
1MB = 1024 KiloBytes = 1,048,576 bytes.

MHz
MegaHertz = 1,000,000 Hertz.

MPEG
Motion Picture Experts Group video compression format for movies or animations.

MySQL
Most popular open-source relational database. Many Unix-based plans allow MySQL databases.

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Operating system
A software heart of the computer. It is a set of programs that manage the hardware resources of a computer, and provide the environment for application programs to run and provide the user interface. Most known operating systems are: different flavors of Unix (SunOs, HP-UX, Irix, FreeBSD, Linux,...), Mac OS and Windows XP and the new Windows Vista.

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Perl
Open source CGI scripting programming language. Written in 1987. Still one of the most popular web programming languages mostly due to its powerful text-manipulation facilities. A huge number of Perl scripts are available for download.

PHP
PHP is an free, open-source server-side scripting language. PHP code can be embedded in HTML. PHP files usually have extensions like .php or .php3. PHP language style is similar to C and Java. Other popular server-side scripting languages are ASP, Perl, ColdFusion, TCL, Python, and JSP.

POP
Post Office Protocol. Popular but inflexible email retrieval standard. All messages are downloaded at the name time and can only be manipulated on a client machine. Current version is POP3.

Port
A socket on the computer or other network device used to connect it to the network.

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RAID
Redundant Array of Independent (or Inexpensive) Disks. Type of disk, often used on servers, where several physical disks are combined into an array for better speed and fault tolerance.

• Level 0 implements data striping where file blocks are written to separate drives. Does not provide fault tolerance, because failure of one drive will result in data loss.
• Level 1 implements data mirroring. Data is duplicated on two drives either through software or hardware. Provides faster read performance than a single drive.
• Level 2 - not used in practice. Data is split at bit level at written to multiple drives.
• Level 3 - requires at least 3 drives. Data block is striped at byte level across drives and error correction codes (parity info) is recorder on another drive. Provides fault tolerance but slower writing performance.
• Level 4 - Similar to Level 3 but provides faster performance because it uses blocks for striping.
• Level 5 - Similar to Level 4 but improves performance but also striping parity info across multiple drives.
• Level 6 - Similar to Level 5 but also uses second parity scheme for better fault tolerance.
• Level 7 - Proprietary RAID design by Storage Computer Corporation. Faster than other levels because it uses multiple levels of cache and asynchronous I/O transfers.

In addition multiple RAID levels can be combined to improve performance or reliability.

Raw Logs
Raw access data updated in real-time that can be downloaded and used by any statistics program. Typically each line show the user's IP, date and time of the access, what kind of request was done, which document was requested, HTTP status code, bytes transferred, referrer, and user agent info. If a host doesn't have statistics, you'll need access to raw logs to identify who your site's visitors are. Analyzing raw logs can also provide more detailed look at site accesses than stats.

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Server
A networked computer that handles client requests for Web pages.

Setup fee
Initial fee charged by a host to set up your hosting account.

Shopping Cart
Software that allows users to select products from a Web catalog, modify their choices, calculate prices, review their choices, and order them. Many hosts with e-commerce plans offer installed shopping carts, but you can always get a shopping cart of your choice instead.

SQL
Structured Query Language. Limited programming language used for updating and performing queries on relational databases. All databases share a common subset of SQL. Most popular SQL databases available with hosting plans are MySQL and MSSQL.

SSH
Secure Shell. Developed by SSH Communications Security, it is a standard for encrypted terminal Internet connections. SSH programs provide strong authentication and encrypted communications, replacing less secure access methods like telnet.

SSI
Server-Side Include. Instructs the server to include some dynamic information in a Web page before it is sent to a client. This dynamic information could be current date, an opinion poll, etc. Many hosts require that SSI pages have .shtml extension to reduce the load on servers by not having to parse non-SSI pages.

SSL
Secure Sockets Layer. Protocol developed by Netscape to provide encryption for commercial transactions data that should be protected while traveling over the Internet, like credit card numbers. SSL uses https protocol. Before using SSL in commerce, you'll also need to get is a certificate from a Certificate Authority.

Static IP
If a host offers a static IP, it means that your site will be assigned a unique and unchanging IP address.

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T1
Dedicated telecommunications line providing 1.5 Mbps of bandwidth. Consists of 24 individual channels, 64 Kbps each, that can be configured for voice or data transmission. T1 lines are normally leased by businesses requiring a dedicated Net connection with higher reliability than a DSL and a faster connection speed than an ISDN line.

T3
Dedicated telecommunications line providing 44 Mbps of bandwidth. T3 lines are often used by ISPs to connect to the Internet backbone.

TCP/IP
Transmission Control Protocol/Internet Protocol. This protocol suite is the de facto standard for today's Internet. TCP is a higher level protocol that runs on top of the IP protocol.

Telnet
Character-based protocol for connecting with remote systems. Still popular among hosts, but it is being replaced by much more secure SSH access.

Terabyte
1024 gigabytes.

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Unix
A family of multi-user operating systems, first developed by AT&T Bell Laboratories in the 1970s and then licensed to many universities. A basis for Linux, a very popular operating system among web hosts.

UPS
Uninterruptible Power Supply. UPS keeps the server running on a battery for several minutes after a power outage, allowing for a clean shutdown for the server or computer without loss of data. UPS can also shield the server from line voltage spikes and drops.

URL
Uniform Resource Locator is a way of addressing used for world wide web. An URL consist of the type of service (protocol), then the host name and then the file on the host.

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VPN
A Virtual Private Network (VPN) is a catchall phrase for a variety of networking schemes that allow businesses to use public Internet lines to create a virtual network. There is no standard model for a VPN, but in general it uses public Internet lines in one of several unique fashions to create a virtual private network. The VPN can operate between branches, regional centers and field representatives via a set of software and hardware protocols that authenticate users and encrypt traffic.

A few types of VPN security include:

• Encrypted tunneling: utilizes SSL (Secure Socket Layer) encryption to authenticate users and send information between the remote client(s) and server(s).
• IP Security (IPsec): encrypts IP packets like SSL, but can also encrypt UDP (user datagram protocol) traffic, one layer deeper in the network model. UDP traffic accounts for only a small percentage of network traffic, but is used in some key applications like streaming media, and Voice over IP (VoIP).
• Point-to-point Protocol (PTPP): Microsoft's VPN protocol, not considered as secure as some others, including IPsec.

Other VPN models include "trusted VPNs," which rely on the third party services of an established network provider. The provider handles all network traffic and guarantees the security of VPN communications. Trusted network structures might use multi-protocol label switching (MPLS), layer-2 forwarding (L2F), layer 2 tunneling protocol (L2TP), or later versions of these protocols, such as L2TP version 3.

A VPN differs from a WAN (wide area network) in that the latter uses leased network lines, thus restricting all traffic to corporate business only. This is effective but costly, particularly when the network must span large distances. Some companies use intranets or extranets to facilitate 'private' communication. These protocols involve password-protected pages or sites that, ideally, only employees and authorized personnel can access. However, connections between remote users and host servers are not always encrypted, and intranets and extranets are not technically private networks. The alternate answer is a VPN.

A VPN is expandable, much more cost-effective than a traditional WAN, connects field operators, international offices, affiliated partners or clients, and improves productivity. Assuming care is taken to build a secure VPN, it is a highly beneficial step that can be a tremendous asset to any company with networking needs.

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WAN
A Wide Area Network (WAN) is a network that spans a large geographical area, the most common example being the Internet. A WAN is contrasted to smaller local area networks (LANs) and metropolitan area networks (MANs). LANs are home or office networks, while a MAN might encompass a campus or service residents of a city, such as in a citywide wireless or WiFi network.

WAV
An audio file format. Very accurate, but offers no compression, resulting in very large files.

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ZIP
A popular file compression utility.

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