Linux
What is Linux?
Linux is a free implementation of a UNIX like operating system for Intel PCs, Alpha, Sparc, PowerPC and other platforms. It has all the features you'd expect from a full featured commercial UNIX system. For more information, visit the Linuc home page.
What can I do with Linux?
Quite a lot. Linux is quite popular in the hobbyist community for a variety of applications, and it's starting to be taken seriously by businesses too. Some of the things Linux can be used for include:
ISP's. As a matter of fact, Quest APANA Public Access Site, where this page is hosted runs Linux. Linux supports all the main Internet services, most "out of the box".
File Servers - Linux supports Windows networking, Novell Netware, Appleshare, and, of course, NFS (native UNIX file sharing). Linux can also mount Windows and Novell shared resources.
Networking - Linux supports TCP/IP, IPX, Appletalk, Amateur Radio AX.25 and others over a wide variety of interfaces, including Ethernet, Token Ring, SLIP, PPP, various radio based devices, PLIP (parallel line IP) and more. With Linux, an old 386 or 486 can be converted into a low cost, full featured router. I use such a 486 running Linux for my PPP link. For those who use an ordinary single user dialup account, Linux, with its IP masquerading feature can be utilised to share that connection among several machines on your Local Area Network. A sophisticated packet filter can be compiled into the kernel (great for protecting your Windows boxes from WinNukes and other nasty attacks), and Virtual Private Networking is also possible, using the inbuilt IP tunneling driver. In short, if it exists, then there's every chance you'll be able to do it with Linux. :-)
X Windows System - X is a distributed graphical user interface for UNIX, and a free implementation, XFree86, is shipped with most Linux distributions. X has a lot of features not found in other well known graphical systems (e.g. Microsoft Windows, OS/2 Warp, MacOS). With X, you can run a program on one machine, and have it display on another system elsewhere on the network. For example, my Linux machine only has a CGA adaptor. I run X applications on the system remotely from a Windows machine running a Windows based X server, saving on hardware costs for the Linux box and RAM on the Windows machine. There are many applications for X under Linux. Some of the more well known ones include: Netscape, Star Office (an office suite), Applixware (another office suite) and Word Perfect 7.
Linux can also run many DOS applications, via the DOSemu DOS emulator. A Windows emulator for X, WINE, is under development as well.
How does it stack up against other operating systems?
Without the right test equipment, I can't do a truly objective evaluation, but from my experience, Linux stands very well alongside more well known systems.
On the desktop, Windows is by far the most popular OS, and looks like remaining that way for some time. However, Linux is far more stable than any version of Windows (including NT), and it's a lot less resource hungry. On the downside, Windows is still easier for the new user to use (though Linux is catching up fast), and Windows has by far the widest range of applications available, especially in the business/office field. It's worth remembering that UNIX, which Linux was modelled after, wasn't originally intended as a desktop operating system, but as a server OS for mainframes and minicomputers. Linux also compares well technically with OS/2, and has a wider range of applications available. OS/2 and Linux with X running use a similar amount of resources.
As a server, Linux becomes more interesting. Linux carries the benefit of its native multiuser capabilities. In addition to the file sharing and client server applications that Windows NT and OS/2 Warp Server support, Linux is capable of interactively handling many users, in both character mode and graphical mode across the network. Each user is totally independent from the others. NT, in its standard form is single user, as far as running apps on the server goes (Citrix did release a modified form of NT that could handle multi user, apparently, there were some problems with some apps though). In effect, the concept of network computing, which is bandied about these days could be implemented by a high powered server running Linux and X terminals or low end PCs with X servers scattered all over the place as "thin clients". Stability wise, Linux is far more stable than Windows NT, with some people reporting uptimes in the order of _years_! I personally haven't seen this, only for the reason that I've had to routinely shut down systems long before that sort of time elapses, but I have had an uptime of 70 days on one Linux box, before a power outage rudely interrupted that record. :-) I have had similar NT uptimes, but this is highly dependent on server hardware and load, and not as consistent as with Linux, where even one server which suspect hardware rarely fails (only happened twice in memory), and the others haven't crashed yet.
NTs GUI interface makes it easier for relative newcomers to learn basic system configuration, but I feel that the same GUI becomes a handicap when trying to customise the system or automate administration functions. Modern distributions of Linux support some degree of GUI administration, but the power of the command line shell and scripting is always available for the experienced administrator to harness. Installation of applications under Linux has progressively become more simplified. When I started using Linux in 1994, the majority of applications required one to download the source code, edit a few header files and then compile it, before installing and configuring the new app. Today, most distributions have some form of package management, which allows you to install your applications in one operation (much like Installshield does for Windows), leaving only the final configuration to complete. That said, the availability of source is convenient, as it allows the administrator to custom build applications when required. Linux itself is distributed with full source code (under its GPL licensing, source must be made available).
I haven't talked about Netware here, as I'm fairly unfimilar with it (I have previously administered an old Netware 3.11 system, but that's a bit unfair, I'd have to compare it with NT 3.1 and Linux 1.0), and haven't seen 4.x in action.
In short, if you want a stable, advanced 32 bit operating system that you can tweak and tinker with to your heart's content, or you simply want something that's "cheap" and works, give Linux a try. I was introduced to Linux as it was reccommended for Quest, and because of that, I became a convert. :-)
Other places for info.
Linux Home Page, the starting point for Linux. Pointers to documentation, user groups, downloads, distributors and more.
And for those in Melbourne... Melbourne Linux Users Group