Apache is a open source HTTP Server management software and is probably the most popular web server automation program. It is developed and maintained by a large community of developers with the help of the Apache Software Foundation. The Apache is available for Unix, GNU, FreeBSD, Linux, Solaris, Novell, Mac OS X, Microsoft Windows  and other operating systems.

MySQL is a relational database management system (RDBMS), which when run on a server, provides multi-user access to a number of databases. There are more than 10 million servers that run MySQL.

PHP is a programming language designed for producing dynamic web pages and is used mainly in server-side application software. Perl and Python are also programing languages.

Linux OS and Linux based servers are very popular because of the open source software collaboration, which allows the source code to be used, modified and redistributed from anyone. The distribution could be commercial or non-commercial under the GNU General Public License. The Linux OS is packaged in a format known as a Linux distribution. Some of the most popular Linux distributions used on web servers are Red Hat Enterprice Linux, CentOS, Debian, (Ubuntu), Fedora and openSUSE.

Often the term Linux Hosting refers to L.A.M.P Hosting service.

The term Cloud Hosting can be also associated with another one – Clustered hosting. Despite that as of May 2011 the term Cloud Hosting is pretty broad term which is not precisely defined yet, we can consider any hosting service as a “Cloud” if it is delivered from a fully-redundant, multi-server system, in which the resources are dynamically scalable and often virtualized.

Virtual Private Server (VPS or VPS Hosting) is a broadly used term which refers to a virtual machine (VM). The virtual machines or VPS are functionally equivalent to a any physical server (dedicated server). Another term – Virtual Dedicated Server (VDS) – also refers to a virtual instance, however it is usually used to explain a virtual server result of different concept of virtualization – Full virtualization.

Any physical dedicated server runs a hypervisor which creates, destroys, and manages the resources of “guest” operating systems or virtual machines. The guest OS are allocated a percentage of resources of the physical machine. The Guest system or VPS may be fully virtualized, paravirtualized, or a hybrid of these two.

In a fully virtualized server, the guest represents an emulated or virtualized set of hardware. It is unaware that this hardware is not strictly physical. The hypervisor translates, maps, and converts requests from the VPS into the appropriate resource requests on the host, resulting in significant overhead.

In a paravirtualized (Paravirtualization) server, the VPS is aware of the hypervisor and interfaces directly with the underlying physical server’s resources. In this virtualization technique the hypervisor implements real-time access control and resource allocation. This results in near-native performance since the VPS sees the same hardware as the physical machine and can thus communicate with it natively. Linux OS supports this method of virtualization.

Advantages of Virtual Private Servers

• Owners and server administrators have full root access to the virtual machine
• Any VPS account is isolated from others accounts on the same physical server
• The VPS owner does not need to deal with hardware or to deal with any replacements or physical upgrades, because the web hosting provider is responsible for the management of the underlying physical server
• From user’s perspective the VPS are easy to be scaled up and down and used on a per demand basis
• A VPS is cheaper than a physical server with similar amount of resources

Disadvantages of Virtual Private Servers

• Compared to any form of Virtual Hosting (Shared Hosting) the VPS are hard to manage, because they require someone to do a system administration and maintenance, OS and applications’ installation, etc.
• Unlike physical dedicated servers, the CPU, RAM, HDD space, disk I/O and other computing resources are still shared between different users of the same underlying physical server. However in some forms of virtualization like Full virtualization, we can not say that the resources are shared.

Reseller Account holder usually act as sellers of Shared Hosting Accounts. The most popular REseller Hosting management interface is cPanel’s WHM.

Shared Hosting services is either name-based or IP-based. In IP-based virtual hosting each Shared account uses a dedicated IP address. The host server is configured with multiple physical network interfaces, or virtual network interfaces on the same physical interface. In name-based virtual hosting all Shared accounts on the server share a single IP address. In name-based hosting Web browsers request a resource from the web server of the host server using HTTP/1.1 which includes a certain hostname as part of the request. The host server uses this information to determine which web site to show the visitor.

Please note that term “Virtual Hosting” has nothing to do with “Virtual Private Server Hosting” (VPS, VPS Hosting, Virtual Servers ).

The most widely used types of name servers are those of the Domain Name System (DNS). The most important function of the DNS servers is to translate (resolve) of domain names and hostnames into Internet Protocol (IP) addresses, which are the second principal Internet name space, used to identify and locate network device, server or computer on the Internet.

The Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating name servers for each domain. Name servers are responsible for their particular domains. The are DNS distributed and fault tolerant. This makes possible for the WWW to avoid keeping everything in a single central register which has to be continually consulted and updated.

Domain Name System also stores information about the list of mail servers that accept email for web addresses. Domain Name System is a very important component of the Internet as we know it because it provides a distributed keyword-based redirection service.

A Domain name is also hostname which identifies Internet Protocol (IP) resources such as web sites. Domain names are formed by the rules and procedures of the Domain Name System (DNS). They are used in various networking contexts and application-specific naming and addressing purposes. Domains are organized in subordinate levels (subdomains) of the DNS root domain, which is nameless.

The first-level set of domain names are the Top-level domains (TLDs), including the generic top-level domains (gTLDs), such as .COM, .NET and .ORG, and the country code Top-level domains (ccTLDs).

There are second-level and third-level domain names in the DNS hierarchy which are open for reservation by end-users as well.