OS (Operating System)

DOS - Windows - OS/2 - Unix - GNU/Linux - BSD - Solaris - etc.

List of most Operating Systems        OS Links

An Operating System is the software that powers a computer . . . command central.  The OS code normally runs in the background, transparent to the user.  Programs interact with the OS directly by subroutines, functions, calls, and API's (Application Programming Interface).  Users interact with the OS through either a CLI (Command-Line Interface), or a GUI (Graphical User Interface).

All major operating systems have their legions of supporters, who claim their OS is the best.  Due to the infinite complexity of each system, a fair comparison is virtually impossible.  However, it is helpful to know a bit about each OS, it's primary features, it advantages and disadvantages, and most important . . . it's popularity.  Why popularity?  Because this assures that the OS will be solidly supported, maintained, and will undergo continuous refinement.  It also means the OS will be used by the masses !!  The name of the game is connectivity and sharing of data  .  .  .  if an OS is unpopular, there are few resources to connect to, and no real future.

Windows, Unix, and Linux are by far the most popular operating systems.  In the Internet server domain, approx 90% are either Windows 2000-NT or Unix boxes.  As far as workstations, approx 80-90% are Windows.

DOS (Disk Operating System)

PC-DOS by IBM,  and  MS-DOS by Microsoft  -  a command-line OS that powered the original IBM computers and x86 clones (XT, AT, 286, 386, 486, Pentiums, etc), and was the substrate OS for Windows 98 and 98.  Windows 2000 and XP do not boot from DOS but they have DOS emulators included, since there are still many useful DOS programs.  DOS and Windows directory paths use a backslash separator ( \ ), whereas UNIX and Linux and the Internet URL's all use a forward slash ( / ).

OS/2 (Operating System v2) and it's newer version, OS/2 Warp 

IBM's answer to the Windows OS for the x86 workstation.  It had a good run there for a while, but has succumbed to Windows.  Oh, they still load it on IBM PC's, but the buyer usually has an option of either OS/2 or Windows, since only including OS/2 would drive buyers away in droves.

BeOS (Be Operating System)

Produced by Be Inc. - this OS is all but dead now, however, there are a few stragglers supporting it.  Be, Inc. sold its intellectual property assets to Palm, Inc. in late 2001.  OpenBeOS project is trying to rewrite and then extend BeOS. The kernel is based on one created by Travis Geiselbrecht called NewOS.  See also BeBits, a repository of BeOS software and beunited.org for the Open Standards BeOS-compatible Operating System (OSBOS) specification. BeOS has the disntinction of the fastest boot times ever (15 secs), crashproof, and no virus has ever been written for BeOS (since no one ever cared).  Travis Geiselbrecht used to be a Be kernel engineer; he wrote NewOS after he got laid off.

POSIX (formerly IEEE-IX)

This OS is IEEE's version of UNIX, and the support site is www.pasc.com 


Microsoft Windows . . . the most popular OS ever . . .  refers to the wonderfully intuitive GUI, which rocketed it to fame - with it's series of customizable windows.  Windows refers to a series of OSes from Microsoft. Early versions were strictly targeted at low-end home computers, while more recent versions have begun tackling the server market. The Windows family of products is the most commonly used operating system on the planet today. While there are many obvious benefits to this, due to it's reptutation for instability and insecurity, many regard this as something of a curse (although realistically the vast majority of computer users neither know nor care about alternatives, and it is questionable whether the alternatives would fare much better with truly widespread deployment). Early versions were based on DOS underpinnings, although the most recent versions no longer contain any legacy code. The following list roughly outlines the evolution of the operating system from it's earliest, relatively unused versions through the current server-oriented releases:



UNIX, written in "C", was originally called "UNICS (Uniplexed Information and Computing System). UNICS was a pun, taken from the acronym MULTICS (Multiplexed Information & Computing Service).  There is no such word (uniplexed) - but the concept is to identify it as "one" (uni) core operating system.  Unix runs on runs on x86 workstations and servers. SCO and SUN were among the first to develop Unix for workstations (SCO for the x86 machines, and SUN for SPARC workstations).

Unix and Windows had an interesting relationship for many years.  Windows was the snappy graphical OS, that user's loved.  UNIX was the lightning-fast but hard-to-use OS that Engineers and Scientists loved.  The user directly runs programs written in C, avoiding all the special graphics in between that Windows offers, and therefore it is faster.  It has less bells and whistles, and can be frustrating to work with, since you must write complex code, and have to master "shell" programming.  

The UNIX GUI - for years, Unix had no GUI, and users had to run ancient editors to create documents - such as ED (Edlin - the standard text editor), VI, Emacs, etc.  Since that time, many text editors have been written for Unix, but most use ED, VI, or Emacs.  Later, a Windows-like GUI was developed, and has become immensely popular.  Many would argue that it is the savior of UNIX, at least for the end user.  The GUI is called X-Window.  Subsequent GUI interfaces, such as Motif and Open-Look, are based on X-Windows.

UNIX offshoots - many companies and communities have created their own flavors of UNIX.  The corporate UNIX versions, are of course, geared to work with their own line of servers.  The free versions, such as OpenBSD and Linux, are made to work with a wide variety of machines and are very customizable - but they are based on the x86 series of computers.  UNIX offshoots include HP-UX, Irix, AIX, DecUNIX, BSD, Solaris, etc.

UNIX has always been a protected, proprietary product, which frustrated the entire programming community.  Enter . . . GNU and then Linux


GNU is not an OS !!!  However, it is such an integral part of Linux that it must be mentioned here.  Actually, GNU is the OS that couldn't  -  it was planned as an OS for years, but it never came to fruition.  Thanks to Linux, it is, at least - the libraries portion of an OS.

First came the open-source code written by a former MIT Engineer, Richard  Stallman.  It was called GNU, which believe it or not, stands for "GNU's NOT Unix".  Unix was frustrating to programmers because they could not get their hands on the patented code.  Stallman decided to write his own operating system, in C, that would mimic Unix.  He founded the GNU Project.  The plan was to create a library of subroutines with the same functionality of Unix, and then finally, write the most difficult part - the kernel.  As it turned out, although he never admitted it, Stallman and his cohorts were excellent C programmers, but did not have the capability to write microcode, which was needed for the high-speed kernel.

GNU's Copyleft Concept - the goal of GNU was to give users freedom, not just to be popular. So they came up with copyleft (as opposed to copyright).  Copyleft uses copyright law, but flips it over to serve the opposite of its usual purpose: instead of a means of privatizing software, it becomes a means of keeping software free.  The central idea of copyleft is that we give everyone permission to run the program, copy the program, modify the program, and distribute modified versions--but not permission to add restrictions of their own. Thus, the crucial freedoms that define "free software" are guaranteed to everyone who has a copy; they become inalienable rights.

Since each component of the GNU system was implemented on a Unix system, each component could run on Unix systems, long before a complete GNU system existed. Some of these programs became popular, and users began extending them and porting them---to the various incompatible versions of Unix, and sometimes to other systems as well.  The process made these programs much more powerful, and attracted both funds and contributors to the GNU project. 

By 1990, the GNU system was almost complete; the only major missing component was the kernel.  GNU was not ready for production use. Fortunately, in 1991, Linus Torvalds developed a Unix-compatible kernel and called it Linux. Around 1992, combining Linux with the not-quite-complete GNU system resulted in a complete free operating system. GNU would have probably died a slow death if not for Linux.  The system is called GNU/Linux  .  .  .  a huge library of C routines, combined with the Linux kernel.

Linux (GNU/Linux)

See www.linux.org .  The term Linux come from it's inventor, Linus Torvalds and it's roots in UNIX.  The purists insist on calling it GNU/Linux, since it is a combination of GNU C libraries and the kernel from Linus.  Linus Torvalds and teams of developers around the world have created Linux under the GNU General Public License.  The source code for Linux is freely available to everyone, and runs on x86 machines.  Go Here to get Linux.

It has been around for quite a while, but for years it was mostly confined to hobbyists, tinkerers and students.  As a corporate server system, it is still considered the new kid on the block.  Linux is competing ferociously, and has made dramatic gains in popularity - especially among the young programmers.  Since it is an open-source code, it has attracted  millions of developers and even basement gurus working on refinements.  Today, creating and selling Linux distributions is a multi-million dollar business. You can buy a boxed version of Linux from companies such as Red Hat, SuSE, Caldera, MandrakeSoft and others. You can also download Linux from any number of companies and individuals. There are distributions of all types and for practically any kind of computing endeavor.

Several years ago, many thought Linux would take over much of the Windows world.  Well it hasn't happened .  .  .  yet.

Commercial Linux

Although Linux is open-source code, corporations want a support team, as well as continuing R&D with their products, including software.  The two most prominent are Red Hat Enterprise Linux and several versions of UnitedLinux - in particular, SuSE.  Each edition of the popular GNU/Linux operating system has different installation, configuration, and hardware support.

Red Hat Enterprise Linux comes in numerous flavors, ranging from a $179 desktop/workstation edition called Enterprise Linux WS Basic Edition to the Enterprise Linux AS Premium Edition we tested. The premium edition, which costs about $2,500, is distinguished from its siblings by clustering capabilities, additional hardware support and service options.

UnitedLinux is a consortium of product/service vendors, comprising founding Linux operating system distributors SuSE LinuxThe SCO GroupConectiva and TurboLinux, and application vendors such as Oracle , which contributed Oracle 9i to the mix. This consortium is an effort to bring a standard code, feature and configuration set to Linux distributions so that applications developed under UnitedLinux can take advantage of standards in each UnitedLinux product.


BSD (Berkeley Software Design)

BSD (Berkeley Software Design), like Linux, is also Unix-based.  It has the misfortune of being available in several versions (OpenBSD, FreeBSD, NetBSD, etc.).  So if you want to use BSD on a grand scale, it is incumbent upon you to research all versions before making a selection. 

There are three other less well-known BSD versions -  Wind River's BSD/OS, which is a commercial offshoot of 4.4BSD and 386BSD and is not freely available . . . Darwin, which is the heart of Apple's OS X . . . and PicoBSD, a version of FreeBSD that fits on a floppy disk, but has not been updated since 1998.


Solaris is Sun Microsystems' version of UNIX, originally developed to run on Sun's SPARC workstations, but can now run on many workstations from other vendors. Solaris includes the SunOS operating system and a windowing system (either OpenWindows or CDE). Solaris currently supports multithreading, symmetric multiprocessing (SMP), integrated TCP/IP networking, and centralized network administration. A Wabi emulator is available to run Windows applications.

There is a huge installed base of Solaris SPARC servers running Oracle !!

Sun's SPARC hardware platform remains a top choice for companies that want to take advantage of the new 64-bit architecture.  Linux has been trying to make inroads with 64-bit SPARC processors, but they have not been widely used to date.

According to Moffitt, 64-bit processors provide greater scalability and more "future-proof" implementations than 32-bit chips. Because a 64-bit chip can handle up to 8 GB of main memory (vs. 4 GB in a 32-bit system), it can better manage processor-intensive tasks. "If you have a large database system, you want to be able to have as much of that database in memory as possible" so that it can manipulate data faster, he said, adding that this feature allows a degree of expandability that a 32-bit architecture cannot match.

Also, contrary to popular belief, 64-bit servers need not be prohibitively expensive. A single-processor SPARC IIi 1U Sunfire V100 server with Solaris preinstalled costs $995, according to Moffitt.