What Is A Server
What Is A Server?
In computing, a server is a computer system that provides services to a network of computers. These services can be diverse in nature, such as files and email. The computers that access the services of a server are called clients. Networks using servers are client-server networks used in medium and large (with many machines) and in networks where the security issue plays a major role. The term is widely applied to server computers, complete, although a server can amount to a software or parts of a computer system, or even a machine that is not necessarily a computer.
The story of the servers obviously has to do with computer networks. Networks allow communication between several computers, with their growth, the idea of devoting a few computers to render some service to the network, while others would use these services. The servers would be responsible for the first function.
With the advent of networks, was a growing need for networks having servers and minicomputers, which eventually contributed to the decrease in the use of mainframes.
The growth of networking companies and the growth of Internet use among professionals and hobbyists alike is the great impetus to the development and improvement of technologies for servers.
Types of Servers
There are several types of servers. The best known are:
- Fax Server: Server for automated transmission and reception of faxes over the Internet, also providing the ability to send, receive and distribute faxes at all stations.
- File Server: A server that stores files to many users.
- Web Server: Server responsible for storing pages from a particular site, ordered by clients through Web browsers.
- Server e-mail: server responsible for storing, sending and receiving electronic mail messages.
- Print Server: Server is responsible for controlling requests for printing files of various clients.
- Database Server: Server that owns and manipulates information in a database, for example, a user registration.
- DNS Server: Servers responsible for the conversion of web addresses into IP addresses and vice versa.
- Proxy server: A server that acts as a cache, storing web pages recently visited, increasing the speed of loading these pages to call them again.
- Image Server: Special type of database server, specialized in storing digital images.
- FTP Server: Allows other users to access a hard drive or server. This type of server stores files to give them access to the Internet.
- Webmail server: server for creating e-mails on the web.
- Server virtualization: allows the creation of virtual machines (servers isolated in the same device) through sharing of hardware, means that increase energy efficiency without harming the applications without risk of conflicts of an actual consolidation.
Clients and servers communicate using protocols as well as two or more network computers.
A computer may occasionally provide more than one service simultaneously. Can exist in a network, a computer that acts as a web server and database server, for example, or a computer can act as a file server, mail servers and proxy at the same time. Computers that act as a single type of server is called a dedicated server. Dedicated servers have the advantage of meeting a request from a client more quickly.
Except for the database server (a server type of application), the other servers only store information, being on the client information processing. In server applications, the roles are reversed, with the client receiving the result of processing data from the server machine.
In a heterogeneous network (with various hardware and software) a client can also be a server and a server can thus be “client account” as “server from the server.” For example, a network has a print server and a file, assuming you are on the file server and need to print a sheet of a document you’re writing, when you have printed the sheet Service of the print server will be used , and so the machine you are using, which is the file server, client is the print server because it is using their service. It is very common in fact that file-sharing networks such as bittorrent, because while a host can be a client for downloading a file, can simultaneously be a server, because other computers can download it from there.
Hardware and software server:
Hardware
Dedicated servers which have a high per share data request from clients and acting on critical applications using specialized hardware for servers. Already servers that do not have those performances may use a common computer hardware.
For starters, many servers are based on inputs and outputs of information (mostly recordings and deletions of files), which involves input and output interfaces and hard drives for high performance and reliability. The hard disk type most commonly used features SCSI standard, which allows the interconnection of several devices arranged in RAID arrays.
Due to work with many inputs and outputs of information, servers require high speed processors, sometimes some are multi-processor servers, or have more than one processor. Servers also have available a large amount of RAM, and is generally used for caching data.
Having to operate for a long time (often seamlessly), some servers are connected to electric generators. Others use power supply systems (eg UPS) to continue to feed the server if any voltage drop.
And, to operate for long periods of time, and due to the existence of one or more high speed processors, servers need an efficient system of heat dissipation, which means cooler more expensive, noisier, but more efficient and reliability.
There are other hardware-specific server, especially plates, like hot swapping, which allows the exchange of these while the computer is turned on, which is critical for the network to continue operating.
There is much debate about whether to use a regular PC, the popular Personal Computer (PC) and server and need to or not to acquire a more robust equipment to act as server. The answer to this question depends on the use of the equipment and the “criticality” of the service that the server is running. In a structure is not critical, a computer can be used as a server. Note that the network size does not matter, for example: a company with 3 instructors online on the Internet has three computers and one of them is the server for Internet access. If this server fails the company’s business is stopped.
Anticipating such a need, manufacturers of computer components develop more robust boards, apply a more elaborate ventilation engineering, redundancy of items and expanded capacity expansion, so the server can guarantee service availability and reliability in the same.
Usually the concern is focused on developing servers in large market makers, who have teams and laboratories prepared for this purpose.
Software
To run a client-server network, it is necessary that the server is installed an operating system that recognizes this type of network. The operating systems for client-server networks are:
- Windows NT, Windows 2000, Windows 2003, Windows XP, Windows Vista, Windows 7.
- Unix.
- Linux.
- Solaris.
- FreeBSD.
- Mac OS X.
- Novell Netware.
The operating systems Windows 95, Windows 98 and Windows ME only recognize the networks point-to-point, and the DOS operating system does not support any type of network.
On servers, the Unix-based systems and this (such as Linux and Solaris) systems are commonly used, while the Windows system, are much less used.
Servers on the Internet
The Internet, the largest computer network in the world, uses the client-server model. Many servers around the world are interlinked and process information simultaneously.
Some services offered by Internet servers are: web pages, electronic mail, file transfer, remote access, instant messaging and others. It is interesting to note that any action taken by a user involves the work of several servers around the world.
Study: From Wikipedia, the free encyclopedia. The text is available under the Creative Commons.
