About Computer Servers
Computer servers are computers that form the heart of computer networks. Also they provide a whole host of services that many computer users take for granted. This article explains what makes a computer server different from an ordinary workstation.
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History
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Servers have been around since the mid-1960s. Back in those days, servers were very large and complex machines that could only be operated by highly trained personnel. Since then,Local Area Netoworks (LANs) began to flourish in workplaces, and the Internet was born and gained in popularity. The media industry needed more affordable and easy-to-manage servers to run their content-management and distribution systems. None of that would be possible without the development of smaller, easier to use computer servers. Today's servers run at an exponentially faster CPU speed than anything from the '60s. It is what has happened in between which is dramatic, and most of the real development has occurred in the last five years.
Many servers today are simply out-of-the-box PCs that are loaded with easy-to-use server software and stuck in a closet or in some other out-of-the-way place. (See the reference to Opera Unite.) But for really heavy-duty networking purposes, there are specially designed computers that are designed just to be operated as servers.
Types
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Server types are classified by functionality and hardware. With regard to functionality, there are file servers and application servers. With regard to hardware, there are (in addition to PCs set up as servers) rack units and blade servers (which are a third of the thickness of a rack-server unit.)
Servers are further delineated by the different operating systems they can run, such as Windows 2008 Server and Apple's Mac OS X Server. Some of the other operating systems include Windows NT Server, LAN Manager, Novell Netware, ICL VME, OSLAN, and Goldrush.
Server file systems were NTFS (Microsoft's "New Technology File System"), HPFS ("High Performance File System") and NFS ("Network File System," the original UNIX network file system by Sun Microsystems.) Today's major network file systems are somewhat restricted to Microsoft Windows NTFS and UNIX/Linux NFS. Whereas the first file systems had no security layer, now file systems for both UNIX and Windows systems have a layer that manages security down to individual files.
Finally there is the platform the operating system is hosted on, such as UNIX/Linux, Mac OS X, and Microsoft Windows. There are other, more obscure systems such as VMS and AS-400 (an IBM system that runs on that company's 'i-series" hardware.) Earlier systems ran on Microsoft OS/2 and IBM OS/2. Today, there are only a few common server systems that have become the choice for reliability and function-richness. -
Uses and Functions
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Whenever you log into a resource at work or on the Internet, you are exchanging your information with a server in order to be able to access that resource.
Between file servers, application servers, and servers that can host databases, e-mail, pictures, sounds and video, there are "intermediate servers." Some servers are set up to do more routine tasks, many of which are "in the background" such as login and password authentication, a vital part of secure log-ins. Other servers are used in the background for translation of human language, computer language (compilation of programs) and interpretation of other languages that make yet more applications run. These are the machines that run "middleware" to pass data from hand-held devices to back-end database servers.
Some servers are used simply as storage repositories for publicly accessible Internet sites, while others are behind firewalls in closed "intranet" settings, and cannot be accessed from outside of the organization's firewall.
Yet more servers run non-stop applications such as telephony or media streaming systems. Those systems are specially designed never to stop running, so that components that fail can be replaced without ever shutting down the system.
Considerations
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Some things that happen on servers depends on what they are used for. For example, an e-mail server writes enormous amounts of data to a server. So does a database application such as Microsoft SQL or Oracle databases. Servers that are used for dedicated storage require special consideration depending on what is being stored. A Storage Area Network (SAN) requires a different method of hook-up from that of a Network-Attached Storage (NAS). A SAN is a cluster of servers, each of which stores block files, like chunks of databases; an NAS is usually only one server that is specially designed to enable sharing individual files over a network, such as documents, images, video, and sound files. The intended purpose of a server is always an important consideration before designing, and purchasing, a server system.
Future of Servers
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Servers will always have a place in our networks. Right now, we can see a wide diversification in their usage. In the future, they will diversify even more, and adopt an even more important role in the way we work. The whole idea of storing anything on a stand-alone hard-drive on your home PC will probably be bypassed in favor of secure server-side storage. The more networks evolve, the more servers will have to be diversified to accommodate the different types of networks, in terms of speed, capacity and bandwidth capability, all of which will be greatly affected by the design, construction and configuration of servers.
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- Photo Credit All images and Screen Shots by Steve Tuffill
