mainframe

Mainframe is an industry term for a large computer, typically manufactured by a large company such as IBM for the commercial applications of Fortune 1000 businesses and other large-scale computing purposes. Historically, a mainframe is associated with centralized rather than distributed computing. Today, IBM refers to its larger processors as large servers and emphasizes that they can be used to serve distributed users and smaller servers in a computing network.

client server

Client/server describes the relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request. Although the client/server idea can be used by programs within a single computer, it is a more important idea in a network. In a network, the client/server model provides a convenient way to interconnect programs that are distributed efficiently across different locations. Computer transactions using the client/server model are very common. For example, to check your bank account from your computer, a client program in your computer forwards your request to a server program at the bank. That program may in turn forward the request to its own client program that sends a request to a database server at another bank computer to retrieve your account balance. The balance is returned back to the bank data client, which in turn serves it back to the client in your personal computer, which displays the information for you. The client/server model has become one of the central ideas of network computing. Most business applications being written today use the client/server model. So does the Internet's main program, TCP/IP. In marketing, the term has been used to distinguish distributed computing by smaller dispersed computers from the "monolithic" centralized computing of mainframe computers. But this distinction has largely disappeared as mainframes and their applications have also turned to the client/server model and become part of network computing.
In the usual client/server model, one server, sometimes called a daemon, is activated and awaits client requests. Typically, multiple client programs share the services of a common server program. Both client programs and server programs are often part of a larger program or application. Relative to the Internet, your Web browser is a client program that requests services (the sending of Web pages or files) from a Web server (which technically is called a Hypertext Transport Protocol or HTTP server) in another computer somewhere on the Internet. Similarly, your computer with TCP/IP installed allows you to make client requests for files from File Transfer Protocol (FTP) servers in other computers on the Internet.

Other program relationship models included master/slave, with one program being in charge of all other programs, and peer-to-peer, with either of two programs able to initiate a transaction.

Web server

A Web server is a program that, using the client/server model and the World Wide Web's Hypertext Transfer Protocol (HTTP), serves the files that form Web pages to Web users (whose computers contain HTTP clients that forward their requests). Every computer on the Internet that contains a Web site must have a Web server program.

Two leading Web servers are Apache, the most widely-installed Web server, and Microsoft's Internet Information Server (IIS). Other Web servers include Novell's Web Server for users of its NetWare operating system and IBM's family of Lotus Domino servers, primarily for IBM's OS/390 and AS/400 customers. Web servers often come as part of a larger package of Internet- and intranet-related programs for serving e-mail, downloading requests for File Transfer Protocol (FTP) files, and building and publishing Web pages.

Considerations in choosing a Web server include how well it works with the operating system and other servers, its ability to handle server-side programming, security characteristics, and publishing, search engine, and site building tools that may come with it.

server

1) In information technology, a server is a computer program that provides services to other computer programs (and their users) in the same or other computers. 2) The computer that a server program runs in is also frequently referred to as a server (though it may be used for other purposes as well).


3) In the client/server programming model, a server is a program that awaits and fulfills requests from client programs in the same or other computers. A given application in a computer may function as a client with requests for services from other programs and also as a server of requests from other programs.


Specific to the Web, a Web server is the computer program (housed in a computer) that serves requested HTML pages or files. A Web client is the requesting program associated with the user. The Web browser in your computer is a client that requests HTML files from Web servers.

hosting

Hosting (also known as Web site hosting, Web hosting, and Webhosting) is the business of housing, serving, and maintaining files for one or more Web sites. More important than the computer space that is provided for Web site files is the fast connection to the Internet. Most hosting services offer connections on T-carrier system lines. Typically, an individual business hosting its own site would require a similar connection and it would be expensive. Using a hosting service lets many companies share the cost of a fast Internet connection for serving files. A number of Internet access providers, such as America Online, offer subscribers free space for a small Web site that is hosted by one of their computers. Geocities is a Web site that offers registered visitors similar free space for a Web site. While these services are free, they are also very basic.

A number of hosting companies describe their services as virtual hosting. Virtual hosting usually implies that their services will be transparent and that each Web site will have its own domain name and set of e-mail addresses. In most usages, hosting and virtual hosting are synonyms. Some hosting companies let you have your own virtual server, the appearance that you are controlling a server that is dedicated entirely to your site.

Dedicated hosting is the provision of a dedicated server machine that is dedicated to the traffic to your Web site. Only very busy sites require dedicated hosting. Many companies purchase their own servers and place them on a site that provides fast access to the Internet. This practice is called colocation.

Dedicated Server

In the Web hosting business, a dedicated server refers to the rental and exclusive use of a computer that includes a Web server, related software, and connection to the Internet, housed in the Web hosting company's premises. A dedicated server is usually needed for a Web site (or set of related company sites) that may develop a considerable amount of traffic - for example, a site that must handle up to 35 million hits a day. The server can usually be configured and operated remotely from the client company. Web hosting companies claim that the use of a dedicated server on their premises saves router, Internet connection, security system, and network administration costs.


In renting a dedicated server, the client company may be required to use a specified computer system or may be offered a choice of several systems. Some host providers allow a client company to purchase and install its own computer server at the host provider's location, a service known as colocation.


Typically, a dedicated server is rented that provides a stated amount of memory, hard disk space, and bandwidth ( here meaning the number of gigabytes of data that can be delivered each month). Some hosting companies allow the renter of a dedicated server to do virtual hosting, in turn renting services on the server to third parties for their Web sites. domain name system, e-mail, and File Transfer Protocol (FTP) capabilities are typically included and some companies provide an easy-to-use control interface.

Managed Hosting - What's it all about?

Do You Need It?

A new trend, appearing in the Web Hosting industry, is the concept of Managed Web Hosting. Web hosts have been offering dedicated servers for a while now, however, because dedicated servers can be difficult to operate technically, there has been a demand for web hosts to provide extra services such as: reporting and monitoring; managed load balancing; managed security; managed storage; and, managed databases.

These extra services are referred to as 'managed hosting'. Do you need it? Before you think about managed hosting you will first need to decide whether or not you need a dedicated server.

You will need a dedicated server if you have a high-traffic web site. If you only have a small web site with low traffic levels then a shared hosting arrangement should be fine. A dedicated server is more expensive to rent and more difficult to operate than a shared hosting solution but if your business depends on a steady service then you should seriously consider renting a dedicated server.

The only disadvantage with dedicated web hosting is that you will have to do a lot of the server administration yourself, and to do this you will need to possess some technical skills; hence the demand for managed hosting.

If you fall into this category of needing a dedicated server but you need your host to provide system administration services such as security, firewalls, monitoring and reporting services, and data backup then most likely you will need managed hosting.