Unix Flavors

Of the other network operating systems available, the various forms of Unix are probably the most popular. It is probably also the oldest of the network operating systems. Bell Labs developed Unix, in part, in 1969. I say “in part” because there are now so many iterations, commonly called flavors, of Unix that it is almost a completely different operating system.

Although the basic architecture of all flavors is the same (32-bit kernel, command-line based, capable of having a graphical interface, as in X Window), the subtle details of each make one flavor better in a particular situation than another.

Unix flavors incorporate a kernel, which constitutes the core of the operating system. The kernel can access hardware and communicate with various types of user interfaces. The two most popular user interfaces are the command-line interface (called a shell) and the graphical interface (X Window). The Unix kernel is similar to the core operating system components of Windows NT and NetWare. In Unix, the kernel is typically simple and, therefore, powerful. Additionally, the kernel can be recompiled to include support for more devices. As a matter of fact, some flavors include the source code so that you can create your own flavor of Unix.

Let’s look at a few of the more popular flavors and their subtleties.

Linux

The Unix flavor that has been receiving the most attention lately is Linux. Linux is a fairly easy-to-use (as Unix goes, anyway) flavor developed by Linus Torvalds at the University of Helsinki, Finland. He started his work in 1991 and released version 1 of the Linux kernel in 1994. At the time of this writing, the current Linux kernel is version 2.2. Since Torvalds adds features daily, it’s only a matter of time before a new release.

Linux runs mainly on the Intel platform, although some distributions run on RISC processors such as the MIPS and Alpha. Attempts have been made, successfully, to run the RISC version on other platforms, such as the Macintosh. Linux is easy to install, and most distributions are free and include the source code. Hardware requirements can vary widely with each distribution.

And there are various flavors of Linux. People acquire Linux, come up with a new feature, recompile Linux with the new feature, and then redistribute Linux. According to Linux’s distribution agreement (called the GNU public license), any sale or distribution must include the source code so that others can also develop custom Linux applications.

Most Linux distributions include a full suite of applications, such as a word processor, the X Window graphical interface, and source code compilers. Additionally, most Unix applications that comply with the POSIX standard should run on Linux with little or no modification.

Because Linux is a flavor of Unix, it comes with network support for TCP/ IP. In particular, Caldera’s OpenLinux is making its mark in the networking world. OpenLinux was developed for corporate networking, so it supports multiple protocols (including PPP [Point-to-Point Protocol], AppleTalk, IPX, and SMB). It also includes support for integration with other network operating systems.

Note 

For more detailed information on Linux, as well as locations to download Linux, check out www.linux.org.

Two other distributions of Linux should be noted: Red Hat and Slackware. Red Hat Linux is the most portable version of Linux, with code that runs natively on the Intel, Alpha, and SPARC processors. The Slackware distribution was specifically designed for the Intel platform and, as such, supports many PC hardware devices, including Ethernet and multiple (up to 16) processors.

Note 

For a list of the various English Linux distributions, check out www.linux.org/dist/english.html.

SCO Unix

The Santa Cruz Operation (SCO), in California, makes two main flavors of Unix: OpenServer and UnixWare. OpenServer is considered the Intel Unix flavor of choice because it is robust and scalable. Corporate networks are favorably inclined toward OpenServer because SCO provides excellent support for its product.

In 1997, Novell sold its Unix product, UnixWare, to SCO. The distinguishing feature of this product is its interoperability with Novell-based networks. Additionally, it is easy to install and administer.

Note 

For more information on OpenServer and other SCO products, check out SCO’s home page at www.sco.com.

Solaris Unix

Of the non-Intel Unix flavors, the most popular is probably Solaris, made by Sun Microsystems. This flavor was designed to run primarily on the SPARC family, a RISC platform developed by Sun. Sun sells both the Solaris operating system and the hardware to run it on, which includes both the logic boards and the systems. These computers running Solaris are widely used as Internet servers.

Not to be outdone by Linux and the SCO flavors, Sun released a version of Solaris for the Intel architecture called Solaris for x86 in 1995. It is designed for use on low-end application and Internet servers.

Solaris is based on the original version of Unix that came out of Bell Labs and, as such, is widely compatible with a number of Unix server applications.

Note 

For more information on Solaris, check out Sun Microsystems’s website at www.sun.com.