The server operating system is the "middleware" of the server system. In many cases, the choice of hardware drives the choice of operating system, but some servers allow for many choices. This chapter explores popular operating systems and what factors to consider when choosing an operating system.
The operating system, as the middleware of the server system, is the program or interface between the actual hardware and the application programs. Because the operating system is a key component of the server solution, selecting one wisely is important, and there are several important considerations. The operating system comprises all the tools that allow the server to be configured, maintained, and backed up, as well as the interface that allows the hardware to connect to the intranet. In many cases, the choices are minimized when the hardware has been selected. Other server hardware requires a decision to be made on the operating system. For example, if your server machine is a Sun computer, you likely will be forced to use Solaris, Sun's version of UNIX. On the other hand, if your server is a Pentium-based machine, you have many options from which to choose. In these cases, a well-selected operating system can be almost transparent to the operation of the server.
When deciding which operating system will run on your server,
first turn to your hardware. Some hardware runs only with specific
operating systems, as specified in Table 7.1. For example, SPARC-based
or Macintosh server hardware has specific operating systems written
by the hardware manufacturer. In some ways, these operating systems
are a great choice, because they are designed, engineered, and
supported specifically for the hardware selected. This eliminates
many issues relating to drivers when installing and configuring
the server. On the other hand, if you choose Intel-based server
hardware, it is refreshing to know that you can select from several
operating systems. However, the fact that you can use anything
from a 386-based machine to an SGI minicomputer as your server
makes the server hardware and software choice more difficult.
Operating System | ||||
Windows NT | ||||
Windows 3.1 | ||||
Windows 95 | ||||
Solaris | ||||
UNIX | ||||
Linux | ||||
MacOS | ||||
SUN OS |
One of the important factors to consider is the level of technical competency of the systems administrator or whoever will be tending to the hardware and software needs of your intranet. If your resident techie is a master at troubleshooting MacOS or Windows problems but has never touched a UNIX box, you should consider using a MacOS or Windows version as the operating system for your server. On the other hand, if you have a UNIX specialist on staff, you can get away with a slower server running a version of UNIX, which is much faster than Windows or Mac.
Your operating system choice also is important for the future of your intranet. If you decide later that your intranet is too large to run on your Windows 95 or MacOS machine, it could be tough to translate some of your custom applications to a UNIX machine.
Many veteran intranet server installers swear by UNIX. It is available for just about all types of servers and in many flavors. UNIX has a long history with the Internet, as much of the Internet was first developed and run on UNIX servers. To this day, the majority of servers on the Internet are UNIX-based. UNIX generally includes TCP/IP as an integral part of the operating system. It also can provide significant performance on less powerful server equipment. Many UNIX systems can run on a small Intel-based 486 server, but UNIX also has the flexibility to run on almost every hardware platform.
A key to UNIX's success in the Internet world is that there are so many knowledgeable UNIX professionals. Some good places to find UNIX administrators (usually) are in Usenet newsgroups. For example, in Washington, D.C., there is a proliferation of them lurking on dc.jobs.
Although UNIX is still the leader in Web sites on the Internet, newer revisions of existing operating systems such as MacOS and Windows NT are quite robust for many sites and deserve a good look. Also, the base of knowledgeable staff available for these newer operating systems is continually growing.
The following sections help you narrow your decisions when it comes to choosing an operating system for your intranet.
Solaris was developed by Sun Microsystems as a more open option of SunOS for its SPARC-based servers and workstations. Sun machines are popular, powerful, and expensive computers built for serving information to many PCs or dumb terminals. Their processors are RISC-based and can perform several tasks simultaneously, as shown in Figure 7.1. Many universities and large corporations use Sun machines to serve information on their networks.
Figure 7.1: Solaris's Open Windows is a graphical interface for Sun's brand of UNIX.
Currently, Solaris has the largest share of the Internet market, mostly because Solaris is the most popular version of UNIX, and Sun has aggressively marketed Internet solutions. Sun spun off the group that developed the operating system into a separate group, Sunsoft. Sunsoft also has ported Solaris into the Intel environment, but with little sales success, mainly because it is difficult and confusing to set up and maintain. It is rare that you will see a 486 machine running Solaris except as an administration tool for a Sun machine. The biggest audience for this operating system is a large corporation or organization that plans on heavy traffic on the intranet. Some of the most poplar sites on the Internet reside on Sun servers. Unless you have an enormous number of users performing complicated tasks constantly, you shouldn't have any trouble with your server slowing down. Another potential audience for Solaris-based servers is companies and organizations that already use Sun machines to run a database or some other network application. For example, if your Oracle database already is running on a SPARC-20, it may be a trivial matter to put a Web server on the machine and use that as your server.
SCO UNIX and BSD/OS are the two most popular commercially available UNIX versions for the Intel platform. The Santa Cruz Operation's SCO UNIX started as a Xenix operating system and was developed and upgraded to the current release called OpenDesktop and OpenServer. These latest releases have graphical user interfaces that prove more friendly than the traditional character-based UNIX operating systems. But don't despair; they are still rooted in the UNIX core and still support character-based commands and use, as shown in Figure 7.2. There are many potential users of these operating systems, from the smallest intranet to the most advanced. The typical user is the organization that wants to make the most of its hardware dollars. A bare-bones UNIX will run well on an Intel 386 machine, and you will be surprised at the performance. If your plan is to run a simple Web server and mail for fewer than 20 users, you should have no problem with the performance of a 386, assuming you have at least 12 to 16MB of RAM.
By the same token, if you have a very busy intranet site serving mail to 100 or more users but don't want to bear the added expense of the hardware, software, and administration of using a Sun or SGI minicomputer, you can squeeze more performance out of a Pentium machine running UNIX than one running Windows 95 or Windows NT. Some intranet developers might want to use UNIX because it provides users with some of the Internet features not available with Windows and MacOS servers. Finger, plan, and vacation mail are standard UNIX features you won't see with many operating systems. Also, UNIX allows for users to have a shell account on the server and server space. If you want your mail to reside on the server and users to read it directly from there, UNIX is the only way to go.
Another nice thing about UNIX is that it is the only operating system that can run on almost any computer. Say you build your intranet on a 386, need to expand to a 486 or Pentium the following year, need to upgrade to a DEC Alpha to handle the traffic the next year, and then possibly a SPARC Ultra. You will have no problem picking the site off one machine and plunking it down on the next.
BSD/OS has seen increasing growth since releasing its product in 1993. BSD, developed by Berkeley Software Design, is based on variations made to the UNIX operating system by students and staff at the University of California. The variations are mostly to the user shell and some functionality; you probably won't notice the difference between versions of UNIX unless you are a serious programmer or UNIX specialist. BSD has targeted the Internet and intranet markets and has a product that is now used to support some of the largest and most popular Web sites on the Internet, such as Adobe and Intel. BSD also has released some gateways to allow its servers to interact easily with sites running Novell Netware.
Linux, shown in Figure 7.3, started in early 1991 as a project by Linus Torvalds, a student in Finland, to test the capabilities of the Intel 386 architecture. By the end of that year the operating system was being distributed free on the Internet and is still free today. To find out where to get various versions of Linux, see http://www.linux.org. It has many proponents, including a large technical user base, but it suffers from a lack of commercial backing, mostly because it is free. Some companies are starting to get into the business of packaging various versions of Linux and distributing it free with books and installation guides.
Figure 7.3: Linux is a shareware UNIX platform built especially for Intel-based machines.
Most of Linux's success is due to its amazing flexibility. Users can modify and customize almost anything in Linux. Imagine being able to design your own operating system and customize it so it is perfect for your needs-this is Linux. If you can learn how, you can do almost anything with Linux. If you are looking to put a site online with little cost and have staff knowledgeable in Linux, it might be the perfect answer.
Windows NT, shown in Figure 7.4, has been in development since the late 1980s, when Microsoft decided that the then-recent release of OS/2 wouldn't cut it as the operating system of the 1990s because of its lack of portability: OS/2 was written specifically for the Intel architecture. Microsoft hired a former DEC engineer and started on the road to an object-oriented, portable operating system.
Figure 7.4: Windows NT 4.0 brings Windows 95's easy-to-use interface to NT.
In its early releases, Windows NT didn't live up to Microsoft's marketing hype as the be-all, end-all operating system, but its latest release has been regarded as stable and robust. It also has begun to receive media and market attention. In the past, Windows NT was available only for servers based on the Intel architecture, but with the latest release, Windows NT has been ported to different server architectures, such as the Alpha, which was developed by DEC. This gives the user who wants to use Windows NT as the operating system more hardware choices. This recent attention has moved Windows NT toward the top of the operating system ladder. As its market share has grown, most system manufacturers now provide Windows NT drivers for their products, and a large base of application developers are porting their products to Windows NT.
Like the UNIX operating system, Windows NT breaks its modules down into two modes: kernel and user. This separation allows the operating system to be more stable, as a module or program running in the user mode is not likely to crash the whole system.
Looking toward the future, Microsoft has released Windows NT 4.0, which includes additional tools that specifically benefit its use as an intranet server operating system, such as IIS 2.0 with NT Server. Time will tell if those tools are based on Microsoft's marketing or if they will actually be useful tools.
Windows NT is likely a good fit in medium to large organizations that plan to have medium to large intranets. These organizations may not be interested in having a UNIX specialist on staff to take care of a single machine. Many companies use Windows NT now as a server for their LAN or WAN. If you already have a Windows NT administrator on staff, it certainly makes sense to use NT as the operating system for your intranet.
OS/2 began with high expectations. In 1987 IBM and Microsoft released it to become the successor to MS-DOS. Within a few years, Microsoft had pulled out of the jointly developed product, and IBM took over all development and marketing. In the early 1990s, OS/2 had developed into a fair platform for client-server computing, and some application developers started using some OS/2 features to gain a foothold in the growing client-server market. In its latest release, OS/2 Warp, IBM has delivered a solid operating system with many features, such as networking and name service built in. Although OS/2 Warp hasn't gained market penetration, it remains a strong robust operating system. The only folks likely to use OS/2 are companies or organizations that are already using it on their LANs or WANs.
In the mid-1980s, Apple developed a new operating system focused on its ease of use: MacOS. To this day, arguably, it offers users the easiest interface of all operating systems. MacOS, shown in Figure 7.5, is the second most-used operating system (as discussed in the section "Market Share: Who Uses What?"). As a Web server, MacOS provides some neat features, including easily configured TCP/IP and Web administration tools. The MacOS also has a strong knowledgeable user base. The main reluctance in using MacOS as an intranet server operating system is in its capacity. As a server, it doesn't efficiently handle more than 50 or so simultaneous users. However, if you are starting with a small pilot in an organization that already has strong MacOS knowledge, MacOS is a good choice.
Figure 7.5: The MacOS has a strong, knowledgeable user base.
There are other operating systems that provide the necessary middleware for supporting an intranet server. Most of these choices, however, are good matches only if your environment is specific to their servers. For example, Novell has released some Web server solutions that allow for supporting a Web site on Novell NetWare. This could be a match for a company with a large investment in Novell servers and Novell's underlying network protocol, IPX.
Other choices might be based on the knowledge factor or existing equipment, as discussed in the previous sections. Such choices might include AIX, IBM's UNIX variant, which runs on IBM's RS/6000 line of servers, or HP/UX, Hewlett-Packard's UNIX variant, which runs on Hewlett-Packard's HP9000 line of servers.
For years, Internet servers have been running UNIX almost exclusively. Again, this is because it is available for just about every type of hardware and there is a large base of knowledgeable UNIX administrators, installers, and programmers-more so than any other operating system. In addition, UNIX is the basis of the beginnings of the Internet.
However, recently, while the cost of technology has been continually decreasing, there has been a consistent increase in the use of easy-to-use graphics-based operating systems. These are highlighted by MacOS and Windows NT, which have been growing faster than any other operating system but still lag far behind Solaris and UNIX. The capabilities of these newer operating systems have been growing to the point that the current release of Windows NT can handle the same loads that were previously only handled under UNIX. However, as you can see in Figure 7.6, Sun Solaris has by far the largest market of Internet servers. Over the next few years, expect to see the difference between the top three or four operating systems narrow as features and benefits become similar among the operating systems and in-house knowledge becomes a larger factor in selecting the operating system.
Figure 7.6: Operating system market share according to a 1995 Internet site survey.
This Internet site survey was created by Jim Fetters of Arizona
State University and administered between April and August 1995;
it included more than 600 responses. The 1996 version of this
survey currently is underway and should be available at http://www.mirai.com
by the time this book is published.
Choosing an operating system for its intranet was a fairly easy task for McKeon & Jeffries. Their systems administrator was very familiar with Windows NT, and the accounting firm was using Windows NT to serve files and the
database.
M&J managers believed that, with 150 users, it was unlikely that they would have more traffic than a Pentium-based machine running NT could handle, and if it does increase, they plan to upgrade to a multiprocessor Pentium or a DEC Alpha. Also, because their database was already running on an NT machine, it would be less difficult to create a gateway from the intranet to the database. |
The SGAA had less of a choice in the matter. Because SGAA decided on the Sun SPARC-20 as the server for its intranet, Solaris was the only choice. The association hired a consultant to help its manager of information services
install the machine and customize it, as well as teach the staff the basics of UNIX administration.
Of course, by using a UNIX-based operating system, the SGAA had a wide range of choices for individual applications to run on its system, including freeware and shareware. |
In most cases, the server hardware selected for a system drives the choice of operating system. So, with your hardware in place, begin narrowing your operating system choice based on that hardware and the relevant knowledge base of your current staff; but remember, sometimes this choice should be based on the functionality of the operating system.