Mac OS X Server

Mac OS X Server is Apple's Unix server operating system. At its core, OS X Server shares a number of components with FreeBSD, and most Linux or xBSD apps can be recompiled fairly easily to run on OS X. According to Apple, Mac OS X Server's full Unix conformance ensures compatibility with existing server and application software.

Based on the same architecture as Mac OS X, Mac OS X Server includes additional services, applications, and administration tools for managing and deploying servers. It's commonly found in small business, education, and large organizations.

Mac OS X Server includes services and applications for cross-platform file sharing, standards-based directory and authentication services, networking and security services, calendaring and scheduling, Web hosting, e-mail services, secure instant messaging, Web-based collaboration, system imaging, live video broadcasting and on-demand video streaming, podcast encode and delivery, client management, and distributed computing. OS X Server 10.6, the Snow Leopard version, features a full 64-bit operating system.

Mac OS X Server 10.6 retails for $999 with an unlimited-client license and $499 for a 10-client license.

Windows Small Business Server 2008

Microsoft's Windows Small Business Server is an integrated server suite that runs the network infrastructure of companies that have fewer than 75 workstations or users. Application server technologies are tightly integrated to enable small businesses with targeted solutions and offer management benefits such as e-mail, Internet connectivity, internal Web sites, remote access, support for mobile devices, file and printer sharing, backup, and restore.

Launched in November, SBS 2008, previously code-named Cougar, comes in two flavors: Standard ($1,089) and Premium ($1,899), the latter of which adds the small-business version of SQL Server 2008 and several other technologies drawn from Windows Server 2008.

The 2008 version is updated to use 64-bit Server 2008 and Exchange 2007. Companies that purchase SBS 2008 will pay 30% to 35% less for the bundle than if they'd bought à la carte software, said Steven VanRoekel, senior director of Windows Server Solutions, who added that companies also will save through utilizing the software to create Web pages or performing IT duties.

Meanwhile, for midsize businesses with more sophisticated IT needs, Windows Essential Business Server 2008, previously code-named Centro, offers a range of additional messaging, management, and security tools. Like SBS 2008, EBS 2008 comes in two editions: Standard is $5,472, and Premium is $7,163.

Linux

There isn't one Linux operating system -- rather, you can buy a boxed version of Linux from a company or download it from a company or an individual. Most Linux server distros run the same Linux kernel but differ considerably in terms of software packages and licensing/support models. Prices range considerably, as well, from free to a couple thousand dollars, which is what the Red Hat server OS tops out at.

The server edition of Ubuntu Linux is free. Backed by the well-funded, for-profit company Canonical, Ubuntu Linux has emerged from relative obscurity to join the top tier of business Linux options. As bMighty's Matthew McKenzie said, "Ubuntu has worked hard to position itself as a good choice for smaller companies that want to minimize their up-front costs without sacrificing the ability to get professional service and support when they need it." He adds that subscription-based distros are an option for companies that will probably heavily rely on a vendor's service and support. Subscription-based distros might also provide a safety net for IT departments that need to "sell" a Linux deployment to risk-averse, non-IT decision makers.

And then there's the "green" aspect of Linux ...

FreeBSD

FreeBSD is developed and maintained by a team of people. It's derived from BSD, a version of Unix. You can check out this article for help choosing a FreeBSD version appropriate for your business. And, obviously, FreeBSD is free.

The open source FreeBSD has been touted as being ideal for high-performance network applications as well as being easy to use. It's the free OS listed most often in Netcraft's list of the 50 Web servers with the longest uptime (meaning no crashes have occurred and no kernel updates have been deemed needed, since installing a new kernel requires a reboot, resetting the uptime counter of the system).

FreeBSD 7 is on version 7.1, released in January. New features include SCTP, UFS journaling, an experimental port of Sun's ZFS file system, GCC4, improved support for the ARM architecture, jemalloc (a memory allocator optimized for parallel computation, which was ported to Firefox 3), and major updates and optimizations relating to network, audio, and SMP performance. Version 8.0 is expected in the third quarter of this year.

Solaris

Sun Microsystems has heavily marketed Solaris for use with its own x64 workstations and servers based on AMD Opteron and Intel Xeon processors, as well as x86 systems manufactured by companies such as Dell, Hewlett-Packard, Intel, Fujitsu Siemens, and IBM. The latest Solaris OS, version 10, added paravirtualization support for when it's used as a guest OS in Xen-based environments such as Sun xVM Server.

The OpenSolaris operating system is a free, open source release that offers a range of support options for businesses. The latest enhancements to OpenSolaris include ZFS, Solaris Containers, and Predictive Self Healing.

Sun began aggressively courting the small- and midsize-business market last year by making available a portfolio of its server, storage, and software products that includes its entry-level Sparc processor-based servers and StorageTek arrays; operating systems including Solaris 10, Windows, and Linux; and its MySQL open source database.

Recently, it was reported that Sun archrival Hewlett-Packard will distribute Solaris 10 on its best-selling ProLiant servers. HP will also sell one- and three-year standard and premium subscriptions for Solaris.