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If you're not familiar with the functions of a server, but have heard the term in passing, you may think of a server as some mystical computer beast that performs amazing tasks and generally is a hands-off system. Before we delve into the inner-workings of a server,
let's start by dispelling that "mystical" thing. From a hardware perspective, a server is simply a computer on your
network that is configured to share
its resources or run applications for the other computers on the network.
You may have a server in place to handle
file or
database sharing between
all users on your network, or have a server configured to allow all users to
share a printer, rather than having a printer hooked up to each individual
computer in your organization.
What makes the term server doubly confusing is that it can refer to both hardware and software. That is, it can be used to describe a
specific software package running on a computer or the computer on which that
software is running. The type of server and the software you would use depends
on the type of network.
LANs and
WANs for example are going to use file and
print servers while the Internet would use
Web servers.
In this article we provide an overview on some of the more common types of
servers such as application servers, database servers, mail servers, and
Web servers.
Application
Server [a
Webopedia definition]
Also called an appserver. A
program that handles all
application
operations between users and an organization's backend business applications or
databases.
Application servers are typically used for complex transaction-based
applications. To support high-end needs, an application server has to have
built-in redundancy, monitors for high-availability, high-performance
distributed application services and support for complex database access.
Print
Server Print servers are set up on a network to route print requests from other
computer workstations on the network. The server handles the print file request
and sends the file to the requested printer where it is spooled. A print server
allows multiple users on a network to share the printer.
Database
Server A database server is an application that is based on the
client/server architecture model. The application
is divided into two parts: a front-end running on a workstation (where users
collect and display the database information) and the back-end running on a
server where the tasks such as data analysis and storage are performed.
Mail Server
[a
Webopedia definition]
Almost as ubiquitous and crucial as
Web servers, mail servers move and store mail over corporate networks (via
LANs
and WANs)
and across the Internet. Today, most people
think of mail servers in terms of the Internet. Mail servers, however, were
originally developed for corporate networks (LANs and WANs).
Web Server
[a
Webopedia definition]
At its core, a Web server serves
static content to a Web
browser by loading
a file from a disk and serving it across the network to a user's Web browser.
This entire exchange is mediated by the browser and server talking to each other
using HTTP. Any
computer can be turned into a Web server by installing server
software and
connecting the machine to the
Internet. There are
many Web server software applications, including public domain software from
NCSA and Apache, and commercial packages from
Microsoft,
Netscape and others.
FTP Server An FTP server is a software application running the
File Transfer
Protocol (FTP), the
protocol for
exchanging files over
the Internet. FTP
works in the same way as HTTP for transferring Web pages from a
server to a user's
browser and SMTP for
transferring electronic
mail across the Internet in that, like these technologies, FTP uses the
Internet's TCP/IP
protocols to enable data transfer. FTP is most commonly used to
download a file from
a server using the Internet or to
upload a file to a
server (e.g., uploading a Web page file to a server).
Proxy Server
[a
Webopedia definition] A
server that sits
between a client
application, such as a Web browser, and a real server. It intercepts all requests to the real
server to see if it can fulfill the requests itself. If not, it forwards the
request to the real server. Proxy servers have two main purposes. Proxy servers
can dramatically improve performance for groups of users. This is because it
saves the results of all requests for a certain amount of time. proxy
servers also Filter Requests to block or disallow specific types of
outgoing or incoming requests to the server.
Different Servers for Different
Jobs
The type of system you would choose for a server depends mainly on its
application within your organization; how much data it will be responsible for
storing and retrieving, the number of
user requests that you expect will be sent
to the server, and how many clients will be accessing the server are all things
you will need to consider before choosing a server
architecture and
software package.
A server is not just one piece of
equipment that has the capability to perform a specific task. From a basic
file/print server, you could be looking at something as common as a Dell PC with
512MB of
memory running
Windows or
Linux and configured to
queue network printing.
An example of midrange server, used for more intensive database storage and
retrieval functions is HP's 900 midrange server with 32
PCI slots and 256GB
of memory to handle the extra workload.
As you can see from this
introduction to the many types and configurations of servers, the term is probably one of
the most ambiguous tech terms you'll ever come across.
Vangie 'Aurora' Beal
Writer, www.Webopedia.com
Last updated: January 28, 2005
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