What is a Server?

What is a Server?

Definition

1. A computer software that manages resources and provides services to users, typically divided into file servers (which allow users to access files on other computers), database servers, and application servers.
2. The computer that runs the above software.

Sometimes, these two definitions can cause confusion, as with web servers. It may refer to the computer used for webpages, or to software like Apache that runs on such a computer to manage webpage components and respond to requests from web browsers.

Server (Computer)

As hardware, a server typically refers to computers that have higher computing power and can provide services to multiple users. There are many differences between servers and PCs, such as PCs usually serving only one user at a time. Servers differ from hosts, as hosts are used through terminals by users, while servers are accessed by client users over the network.

Based on different computing capabilities, servers can be classified into workgroup servers, departmental servers, and enterprise servers. Server operating systems refer to the operating systems that run on server hardware. Server operating systems need to manage and fully utilize the computing power of server hardware and provide it for use by software on the server hardware.

Currently, there are many operating systems designed for servers available in the market. Unix-like operating systems, being descendants of Unix, generally possess better features for serving as server platforms. Common Unix-like server operating systems include AIX, HP-UX, IRIX, Linux, FreeBSD, Solaris, Mac OS X Server, OpenBSD, NetBSD, and SCO OpenServer. Microsoft has also released Microsoft Windows Server versions, such as the earlier Windows NT Server, later Windows 2000 Server, Windows Server 2003, and the current Windows Server 2012.

Server Software

The definition of server software, as previously mentioned, works in a client-server or browser-server manner, with many forms of servers commonly used, including:

• File Server - like Novell's NetWare
• Database Server - like Oracle Database Server, MySQL, PostgreSQL, Microsoft SQL Server, etc.
• Mail Server - Sendmail, Postfix, Qmail, Microsoft Exchange, Lotus Domino, etc.
• Web Server - like Apache, thttpd, Microsoft IIS, etc.
• FTP Server - Pureftpd, Proftpd, WU-ftpd, Serv-U, etc.
• DNS Server - like Bind9, etc.
• Application Server - like Bea's WebLogic, JBoss, Sun's GlassFish
• Proxy Server - like Squid cache
• Computer Name Resolution Server - like Microsoft's WINS server