Networking / Beginners

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Microsoft Windows Server

Windows NT Server, the first edition of Microsoft's popular server software, emerged out of the breakup of IBM and Microsoft's shared OS/2 initiative. Although Windows Server OSs offer a fairly simple graphical user interface (GUI), it's a true multitasking, multithreaded NOS.

Since Windows NT was introduced in 1993-1994, Microsoft has weathered a storm of criticism regarding its reliability, scalability, and robustness. To be fair, some of this criticism has been deserved because some releases of the Windows NOS have had a number of flaws. However, Microsoft has persevered and continued to refine its NOS as it passes through product cycles (NT Server 3.5 to NT Server 4 to Windows 2000 Server to Windows Server 2003), up to and including the current iteration, Windows Server 2008.

The most significant change in the Microsoft server products was the upgrade of the Microsoft NOS from NT Server 4 to Windows 2000 Server. Microsoft's flat domain model was replaced by a hierarchical directory service called Active Directory. Active Directory holds all the objects that exist on the network, including domains, servers, users, and groups. Active Directory allowed Microsoft to compete on a level playing field with NetWare's NDS (now eDirectory) and Sun's Network Information Service.

UNIX and Linux

Unlike NetWare or Windows NT, UNIX is not a monolithic OS owned by a single corporation. Instead, it's represented by a plethora of manufacturers with only a few clear standouts. The most common UNIX systems are Sun Microsystems' Solaris, IBM's AIX, and Hewlett-Packard's HP-UX.

In the PC-hardware world, Linux, a UNIX clone, has trumped various UNIX systems, including commercial variants such as Santa Cruz Operation's SCO UNIX, Novell's UNIXWare, and Sun's Solaris for Intel. Linux has also grabbed greater market share than other community-based OS developments such as BSD (Berkeley Standard Distribution), OpenBSD, and FreeBSD.

UNIX and UNIX-like OSs come in many flavors, and some features and commands vary widely between versions. In the end, though, it remains the most widely used high-end server OS in the world.

However, the UNIX world is fragmented by a host of issues that derive from UNIX's basic design: UNIX is open-ended and is available for almost any hardware platform. UNIX has existed for more than 30 years, and its design has been optimized, revised, and improved to the point at which it's quite reliable.

Unfortunately, the availability of UNIX across many different platforms has led to one significant problem that blocks its widespread adoption: Software written for one version of UNIX usually doesn't run on other versions. This lack of compatibility has led to UNIX receiving a dwindling share of the server market except at the very high end where absolute reliability is a must. Linux and the Open Source/GNU movement have ameliorated a good deal of the incompatibility issues by ensuring that the source code for most Linux-based software is available. This means that with a copy of Linux with a C-language compiler, you can compile-that is, translate from source code to machine instructions-a variety of software.

UNIX has a reputation for being difficult to master. It's complex; there's no doubt about that. But after you assimilate the basics (which can prove daunting), UNIX's raw power and versatility make it an attractive server platform.

Interestingly, Linux, which is essentially a UNIX clone, has begun to make a great deal of headway in the server and workstation market. It's begun to put a dent in Microsoft's market share both in the server and desktop OS categories In spite of its complexity, however, any version of UNIX makes for efficient file, print, and application servers. Because of 30 years of refinement, the reliability of a UNIX system is usually a step above that of other platforms. UNIX uses the TCP/IP networking protocol stack natively; TCP/IP was created on and for UNIX systems, and the "port-and-socket" interface that lies under TCP/IP has its fullest expression on UNIX systems.

Most of our discussion will relate to Linux because its open source development makes it an inexpensive and intriguing NOS to explore. Linux has become a cost-effective and viable alternative to some of the standard NOSs, such as NetWare and Microsoft Windows Server.