Knowledgebase
Glossary from F to L
This is a glossary of terms, phrases and concepts related to web hosting, web applications and the Internet in general.
The glossary is in four parts. This one covers terms that start with the letters from F to L. Here are links to the other parts:
FastCGI - this is a variation of CGI. As the name suggests it's designed to be faster than plain CGI, but it's less stable. With FastCGI the server can process more user requests at the same time. One process can cope with many requests, while with plain CGI a new process is started for each request.
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File permissions - when referring to the files and folders on a hosting account, the permissions of a file/directory specify whether a user can view, edit and execute the file. Each file and folder has a set of three permissions. The first one is for the owner of the file, the second one for the group of people that have access to the account and the third is for all the visitors on your site. The permissions can be expressed either with letters or with numbers. When they are expressed with letters the first three letters are for the owner, the next three are for the group and the last three for all the visitors; for example, rwxr-xr-x stands for read, write, execute for the owner, read and execute for the group, and read and execute for the others. The same permissions expressed with numbers would be 755.
File and folder permissions can be changed on the hosting account with an FTP client, from the control panel or via SSH. For general information on file permissions and how to change them with an FTP client check our tutorial on file permissions and how to change them. For information on how to do this via SSH check our article on how to change file and folder permissions via SSH.
Firewall - a system that improves the security of a computer or a network by monitoring the traffic between a local computer (or a network) and another network such as the Internet. If necessary and there's a potential security risk, it can block that traffic. As the name suggests, it can be viewed as a wall that protects the local computer/network from unauthorized access. Operating systems (e.g. Windows) usually come prepackaged with a firewall. Many anti-virus applications also include a firewall. Network devices such as routers usually have a built-in firewall.
Freeware - software that can be used for free. There may be some restrictions; for example, the freeware may be only for private use, or it can be a version with limited options and capabilities, and a paid upgraded version with more options may be offered.
Freeware doesn't necessarily have to be open source. It may be open source or proprietary (i.e. closed source).
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Front-end - a term used in relation to web applications for building and managing websites. Such applications make the distinction between the front-end of the site, which is the actual site that visitor see, and the administration panel (also called the backend) from which the site is managed.
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FTP (stands for File Transfer Protocol) - an Internet protocol for transferring files between a local computer and a server. This can be done with applications called FTP clients. With an FTP client you can upload files from your computer to your hosting account and download files from your hosting account to your local computer.
FTP client - an application for transferring files via FTP (File Transfer Protocol) between a local computer and a server on the Internet. In addition to transferring files you can also use the FTP client to perform some other tasks with the files on the server (delete, rename, change permissions, etc.). There are many different FTP clients; some popular ones are, for example, FileZilla and CuteFTP.
For information on how to configure different FTP clients you can check out our FTP tutorials.
Gecko - the web-browser engine used in Mozilla Firefox and other Mozilla applications (e.g. Thunderbird, SeaMonkey, etc.). It's also used in web-browsers developed by other companies, and also for other types of applications, not just for web-browsers. Gecko is open source and free.
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GIF (stands for Graphics Interchange Format) - a file format for storing digital images. Images that are saved with the GIF format are compressed to reduce the size of the files, and the compression technique is lossless, which means that the quality is preserved without any losses after the compression.
The color depth that GIF supports is 8 bits per pixel which means that it can display a total of 256 colors. In comparison other image formats (e.g. JPEG, PNG) support many more colors. So GIF is usually not used for pictures but for simpler images with fewer colors such as logos, for example. Files in the GIF format have the file extension .gif (e.g. example_image.gif).
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Grayware - refers to software applications that pose security risks and slow down the performance of the computer. These applications don't contain any viruses or worms, for example, but are considered a nuisance and cause other problems for the user.
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GZIP - refers both to a file format and a software application for compressing and decompressing files. GZIP files have the extension .gz (example_file.gz). Usually it's used to compress tar archives, and in such a case the resulting archive file will have either the extension .tar.gz or .tgz. The GZIP file format is used very often when a bunch of files have to be transferred. For example, when you download an application from the Internet it may be a GZIP archive. Other popular file formats that are used for compression are ZIP and BZIP2.
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GUI (stands for Graphical User Interface) - a term that is used for software applications that have a visual interface with which the user can interact and perform tasks (e.g. by clicking on icons, buttons, etc.). The majority of applications are GUI applications.
There are applications that don't have a graphical interface but a command-line interface (also called console user interface); with such applications tasks are performed by typing commands.
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Hexadecimal - a term used in mathematics and computing. It refers to a system of 16 characters/symbols. Usually the numbers from 0 to 9 and the letters from A to F are used. Hexadecimal digits are mainly used to show binary code in a form which is easier for people to remember; it's more human-friendly. One hexadecimal digit represents four bits.
One example use of hexadecimal digits is for MAC addresses of LAN adapters.
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Honeypot - refers to technologies used to detect unauthorized access to a computer network. A honeypot can be compared to a trap that is set against spammers and intruders. It can be used to protect websites and networks.
It simulates data that abusers think that it may be exploited by them, but it's a controlled environment which is monitored and is separated from the data it protects. It's used to deflect the abuser and gather information about them (e.g. IP address). There are different types of honeypots that are designed to protect against various types of attacks (e.g. spam, malware, SQL injections, etc.).
Hop - when used in relation to the Internet (and networks in general), it refers to one step of the way between the source and the destination device. For example, let's say that you request from your local computer a resource (e.g. a website) that's stored on a server. Your local computer and the server are not connected directly to each other; there are other servers and routers between them. The data that's transferred between the local computer and the server has to pass through these other devices. Each portion of this way is a hop. So the hop count corresponds to the number of devices through which the data has to pass from the source to the destination. If there are ten devices between the local computer and the destination server, then the hop count will be 10.
The hop count can be determined with commands such as ping and tracert/traceroute executed with a command-line tool (e.g. cmd in Windows).
Hop count - the number of devices between the source (e.g. local computer) and destination (e.g. server) through which a request passes in a network.
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Host - a computer connected to a network such as the Internet. It usually provides services to other computers on the network. For example, a web server is an Internet host.
Hosting provider - a company that provides hosting services (e.g. web hosting, email hosting, etc.). Customers can use these services to publish and have their website accessible on the Internet, to send and receive emails, etc.
Hostname - the terms domain name and hostname are often used interchangeably. They are pretty much the same thing, but there's a slight difference. The term hostname is a more general one that can be applied not only to the Internet, but also to other computer networks, while domain names are specifically used for the Internet. A domain name is also considered a hostname if it is associated with an IP address.
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hosts file - a file on the local computer that's used for mapping domain names to IP addresses. Its location depends on the operating system. It's a text file that can be edited by the user. The user can specify a domain name(s) and the IP address to which they want it to be mapped. When there's a request from the computer for the particular domain name, the web browser will send a request for the IP address specified in the hosts file. This can be used for various purposes; for example, harmful websites can be blocked so that they cannot be accessed from the computer.
For more information on the hosts file, how to use it and its location in Windows operating systems check out our article on hosts file and how to use it.
.htaccess file - a configuration file that gives instructions to the server on how to process various aspects of your website. It's a file type that's used by the Apache web-server (All HostKnox servers use Apache). The .htaccess files can be placed in directories on the hosting account; they override the global configuration of the server. This is done by putting directives in the .htaccess file. They can be used for various things: to protect content on your site, to redirect content, to cache content, etc.
For more details on .htaccess files and for information on how to do various things and tricks with .htaccess, check out the articles on .htaccess in our knowledge base.
HTML (stands for HyperText Markup Language) - a markup language for creating hypertext documents, or in other words this is the language for creating web pages. It's not a programming language but rather a descriptive one. It describes the structure of the web page (e.g. which parts are paragraphs, which ones are headings, etc.). This is done with HTML tags. The web-browser reads these tags and displays the page without showing the actual tags.
HTML can also be used to define how the text and elements on the page should look in terms of style, but this is usually done with CSS (Cascading Style Sheets) files.
HTTP (stands for HyperText Transfer Protocol) - one of the main and most widely used Internet protocols. Web pages are requested and transferred through HTTP.
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HTTPS (stands for HyperText Transfer Protocol Secure) - this is the secure version of the HTTP protocol. It's a combination of HTTP and the SSL/TLS security protocol; the HTTP protocol is used over SSL/TLS. In this way the data transfer is encrypted.
Hypertext - text shown by a computer (or another device) that contains hyperlinks to another text(s). Most typically it's used on the Internet for displaying web pages; it makes it possible to easily link to other pages and to share information. It's created with the help of a markup language like the Hypertext Markup Language (HTML).
ICMP (Internet Control Message Protocol) - a network protocol that's used for sending error messages informing that a request on the Internet cannot be completed; for example, when a server can't be reached.
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IETF (stands for Internet Engineering Task Force) - an organization of volunteers which develops and improves various Internet specifications and standards. It deals mostly with the Internet protocol suite (TCP/IP). The documents published by the organization are called Request for Comments (RFC) and are publicly available on the Internet.
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IIS (stands for Internet Information Services) - a web server software developed by Microsoft. HostKnox servers don't use IIS.
ImageMagick - an open-source collection of computer programs for manipulating images. The programs in the suite are with command-line interfaces. HostKnox servers do not support ImageMagick.
IMAP (stands for Internet Message Access Protocol) - an Internet protocol with which email messages are accessed and managed directly on the server. Mailboxes can be accessed via IMAP with an email client (e.g. Mozilla Thunderbird). When IMAP is used there's no need for the messages to be downloaded on the local computer. They can be managed on the server.
The port number through which the server establishes a connection via IMAP is 143. If a secure connection is used (IMAP over SSL/TLS), the port number is 993.
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InnoDB - a type of MySQL database engine (also called store engine). The database engine is the actual software through which the database management system (e.g. MySQL) performs actions with the database (e.g. creates, updates information, etc.). One database management system can support different database engines. InnoDB has become the default database engine for MySQL version 5.5 and newer.
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Internet - a computer network that consists of smaller networks. When people refer to the Internet with a capital letter, this is the biggest network that links all other networks. The Internet is used for various services. One of the most widely used services that functions with the help of the Internet is the World Wide Web. The World Wide Web is a collection of webpages and the Internet provides the infrastructure for them to be interlinked and accessible to users.
The Internet protocol suite (TCP/IP) specifies how connections are established and how data is transferred over the Internet. The standards of the protocols in the suite are developed and maintained by an organization called the Internet Engineering Task Force (IETF).
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Internet protocol suite - usually referred to as just TCP/IP because of the two most important protocols in the suite: TCP (Transmission Control Protocol) and IP (Internet Protocol). This is a set of protocols that specify how data should be transferred over the Internet from one end of the connection to the other. The process and the protocols are organized into layers: link layer, internet layer, transport layer and application layer.
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Intranet - a computer network of an organization that's closed for external access and uses Internet technologies, such as the protocols of the Internet protocol suite (TCP/IP), to function.
IP (stands for Internet Protocol) - one of the two main protocols in the Internet protocol suite. In an Internet connection its function is to transfer data (formatted into packets) from the source end of the connection to the destination. It identifies the hosts in the connection and provides the IP addresses in the data packets.
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IP address - each computer or other device that's connected to a network that uses the TCP/IP protocol suite (such as the Internet) has an IP address with which it's identified. Whether it's a local computer or a server it has an IP address. An IP address consists of numbers, and its form depends on whether the Internet Protocol Version 4 (IPv4) or version 6 is used (IPv6). Predominantly, version 4 is used and with it the IP address consists of four numbers from 0 to 255, each separated from the other with a dot (e.g. 235.51.3.124).
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ISP (stands for Internet Service Provider) - as the name suggests, that's a company that provides access to the Internet.
Java - a computer programming language. One of its primary advantages is that it's designed in such a way so that it can be used on different platforms and operating systems without the need to be changed or recompiled. It's not to be confused with JavaScript; they are different programming languages.
HostKnox servers don't support Java.
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JavaScript - a client-side scripting language, though in rare cases it can also be used for server-side programming. As a client-side scripting language, when the web page contains JavaScript code, it's executed by the web-browser of the user.
JavaScript is not to be confused with Java.
Joomla - a CMS (Content Management System) for building and managing websites. It's designed so that it can be easily used from people who have no programming knowledge whatsoever. It's one of the most popular web applications for creating websites. It's open source and free.
HostKnox provides Joomla hosting services and an ideal environment for running Joomla sites. You can find more information on how to install and use Joomla in our Joomla tutorials and the Joomla articles in our knowledge base.
JPEG (acronym for Joint Photographic Experts Group) - a popular file format for compressing and storing images. It's also called JPG and JFIF. Actually, JPEG is used to compress different image formats but usually they are all just called JPEG. It has a good ratio between compression and the loss of quality, so JPEG images have a small file size and a very good visual quality. This makes JPEG the most widely used image format for photographs and pictures on the Internet. JPEG is less suitable if the image contains graphics and text (images with sudden transitions of colors). This doesn't mean the quality of such images will be bad, but that other image formats such as PNG might be more suitable for the particular image(s).
Since the data compression that JPEG uses leads to some loss of data (worsening of the quality), it is not as suitable as other formats if the image has to be edited frequently.
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JPG - see JPEG
JSP (Java Server Pages) - a server-side technology developed by Sun Microsystems and used for dynamic web pages. It uses the Java scripting language. HostKnox servers do not support JSP and Java.
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Kernel - the central component, the core, of a computer operating system. This is the part of the operating system that makes it possible for the hardware of the computer (e.g. CPU, memory, etc.) to connect and exchange data with the software.
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LAMP - an acronym that stands for Linux, Apache web server, MySQL and PHP (or Perl or Python). This is a set of software solutions (a solution stack) that provide all the elements that are needed for running web applications and websites. It's one of the most popular solution stacks.
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LAN (Local Area Network) - refers to a network of computers in which the connected computers are located on a small area. Usually the computers connected in a LAN are in the same building though the area can be much wider (e.g. a street, a neighborhood).
The most widely used technology for building LANs is Ethernet. With this technology the computers are connected with a cable. A common technology for creating wireless LANs is Wi-Fi.
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LAN adapter - see NIC (Network Interface Controller)
Linux - a free, open-source computer operating system. It can be used on servers, personal computers and other devices. When it comes to servers it's one of the most popular and widely used operating systems. There are many different Linux distributions (e.g. Debian, Ubuntu, etc.). A Linux distribution is an operating system that includes the Linux kernel and a package of software applications. It can have either a graphical or a command-line interface. Those for personal computers usually have a graphical interface, but a command-line can also be used.
HostKnox servers run on Debian Linux.
Local - when used in relation to web hosting and the Internet, local is used to refer to the computer with which the user accesses the Internet and everything that runs on that computer.
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Lossless data compression - refers to methods for compressing data with which the data is compressed in such a way so that when it's uncompressed there's no loss of data, and it's identical to the original. Examples of file formats that use such data compression are ZIP and PNG (for images).
Lossy data compression - refers to algorithms for compressing data with which there's some loss of data in the compressed file as compared to the original. Such compression methods are usually used for compressing images, audio and video. The result of using lossy compression for multimedia is that the compressed file has a quality that's worse than the original. The advantage is that the size of the file is smaller than that of the original. Examples of file formats that use lossy data compression are JPEG (images), MP3 (audio), MPEG (video).
There are also lossless data compression methods with which the data is compressed in a way so that it's preserved exactly as the original. However files compressed with lossless data compression are bigger than those compressed with lossy data compression.