Compare the strengths of Linux, Unix, Solaris, NT

By Barry NanceSpecial to GCNWhat's to choose from in an operating system?It depends what you want or need most: scalability or a good price, security or application support. Consider the differences between the various versions of Microsoft Windows NT, Unix and Linux.You can think of Linux as an incarnation of Unix. Linux source code, written and maintained by scores of collaborating programmers around the world, is available for free. Red Hat Inc. and Caldera Inc. add value to Linux in the form of extra software.To the basic Linux kernel, for example, Caldera's OpenLinux adds the X Window System, developer tools, Apache Web Server, Java Development Kit, Netscape Gold, Netscape FastTrack Web server and Hypertext Markup Language editing tools. Netscape FastTrack Server 2.0 is an entry-level Web server that's great for publishing static Web pages but less than useful for serious dynamic HTML work or three-tier Web applications.Linux is simple and about as robust as NT. In my tests, it terminated rather clumsily when confronted with nontrivial processor, memory and hardware failures. It also lacks the breadth of application tools, such as word processor and spreadsheet programs, that are common to the leading office suites.SunSoft Solaris and Hewlett-Packard's HP-UX are more forgiving of hardware problems. Solaris detects most such problems automatically and sends an e-mail note or problem message to a technician. HP-UX goes a step further, automatically configuring the computer to avoid the failed hardware component and, for most failures, lets the technician repair the problematic component without powering off the computer.Installation and administration of OpenLinux is almost wholly manual compared with other versions of Unix. For instance, OpenLinux requires that you manually create the swap and primary Linux partitions. You'll also likely have to manually fine-tune your monitor, video card and mouse settings before you can start the X Window server.Solaris is the most popular version of Unix among government users, and the latest version has several new features for Internet and intranet use. It also integrates well with NT Server for file sharing. Solaris is more scalable, reliable and secure than NT. On the other hand, computers built with Intel Corp. chips are much cheaper than Sun Microsystems Inc.'s Sparc machines.Agencies migrating to Solaris 7 include research groups run by the Commerce and Energy departments; meanwhile, the Defense Department is using it for its DOD-wide travel system. Solaris 7 is also available on the Navy's Tactical Advanced Computer Joint Workstation blanket purchasing agreement and NASA's Scientific and Engineering Workstation Procurement II contracts.For running Common Gateway Interface Web applications'those with form statements embedded in HTML'Solaris is a fast performer. Solaris' task- and process-management functions are quicker and more efficient than those of other operating systems. This is an important because CGI places a heavy burden on an OS' ability to launch programs.Solaris, not surprisingly, has superior Java support. Sun offers Solaris for Intel and Sparc CPUs, a strategy that lets the company scale Solaris down for use on inexpensive desktop machines.Solaris is easy to configure, and its ability to perform most administrative tasks remotely over a network is a big plus. I tested both Sun's command-line utilities and Web Start browser interface to manage system resources, including partition sizes, available sockets, maximum threads per user and other parameters. The Java configuration utilities are generally intuitive and, because of the effectiveness of Sun's Just In Time compiler, highly responsive.Version 7 is faster than previous Solaris versions. Sun improved the OS' disk input/output and the TCP/IP protocol stack drivers.Security is an area in which Solaris needs improvement. Version 7 can use Plug-In Authentication Modules, as well as the General Security Service-Application Programming Interface standard, and the OS offers Virtual Private Network security. But Solaris lacks transport layer security and the ability to restrict access for specified hours of operation. It is much easier to batten down the hatches on HP-UX than Solaris.NT Server is an OS with myriad uses and features, such as Active Server Page Web scripting, file serving, transaction processing monitoring via Transaction Server and the Microsoft Management Console.NT has a remote Web management interface and a Basic-like language for scripting configuration changes. It also has the widest range of third-party development tools among OSes.Unfortunately, too many kinds of NT configuration changes require rebooting. NT is unable to gracefully survive machine checks, disk space exhaustion and its own rare OS bugs, so you must keep a watchful eye on its day-to-day operation.NT is eminently suitable for running distributed or Web apps, as long as they don't require around-the-clock uptime.SCO UnixWare 7 is the latest result of Santa Cruz Operation Inc.'s efforts to unify and consolidate its Unix products. The new UnixWare release, which is based on the Unix System V Release 5 kernel, exhibits a number of improvements that provide better performance and reliability.The improvements indicate that SCO, the current holder of the AT&T System V source code, might produce the first 64-bit Unix for Intel chips when Intel releases its Merced processor later this year.The SCO UnixWare kernel has a rewritten networking subsystem that handles LAN traffic quickly and efficiently. It integrates nonuniform memory architecture with support for up to 16G of main memory, 2T file systems and up to 512 disks. Maximum process size is 3.75G, and a single file can use up to 1T.