This document can serve as an introduction to Linux for Windows users

Both Windows and Linux come in many flavors. All the flavors of Windows come from Microsoft, the various distributions of Linux come from different companies (i.e. LindowsLindows, Lycoris, Lindows, Lycoris, , Lindows, Lycoris, , , Lindows, Lycoris, , , ,

The flavors of Linux are referred to as distributions (often shortened to "distros").All the Linux distributions released around the same time frame will use the same kernel (the guts of the Operating System). They differ in the add-on software provided, GUI, install process, price, documentation and technical support. Both Linux and Windows come in desktop and server editions.

There may be too many distributions of Linux, it's possible that this is hurting Linux in the marketplace. I suspect that the lack of a Linux distro from a major computer company is also hurting it in the marketplace. Perhaps this will change with Novell's purchase of SuSE.

Linux is customizable in a way that Windows is not. There are many special purpose versions of Linux above and beyond the full blown distributions described above. For example, NASLite is a version of Linux that runs off a single floppy disk and converts an old computer into a file server. This ultra small edition of Linux is capable of networking, file sharing and being a web server.

Graphical User Interface:

Both Linux and Windows provide a GUI and a command line interface. The Windows GUI has changed from Windows 3.1 to Windows 95 (drastically) to Windows 2000 (slightly) to Windows XP (fairly large) and is slated to change again with the next version of Windows, the one that will replace XP. Windows XP was the first version of Windows to allow a GUI choice. It can be used with either its new GUI or one more like Windows 2000 and Windows 9x. Linux typically provides two GUIs, KDE and Gnome. See a screen shot of Lycoris and Lindows in action from the Wal-Mart web site. Of the major Linux distributions, Lindows has made their user interface look more like Windows than the others. Then too, there is XPde for Linux which really makes Linux look like Windows. Quoting their web site "It's a desktop environment (XPde) and a window manager (XPwm) for Linux. It tries to make easier for Windows XP users to use a Linux box."

Text Mode Interface:

This is also known as a command interpreter. Windows users sometimes call it a DOS prompt. Linux users refer to it as a shell. Each version of Windows has a single command interpreter, but the different flavors of Windows have different interpreters. In general, the command interpreters in the Windows 9x series are very similar to each other and the NT class versions of Windows (NT, 2000, XP) also have similar command interpreters. There are however differences between a windows 9x command interpreter and one in an NT class flavor of Windows. Linux, like all versions of Unix, supports multiple command interpreters, but it usually uses one called BASH (Bourne Again Shell). Others are the Korn shell, the Bourne shell, ash and the C shell (pun, no doubt, intended).

Cost:

For desktop or home use, Linux is very cheap or free, Windows is expensive. For server use, Linux is very cheap compared to Windows. Microsoft allows a single copy of Windows to be used on only one computer. Starting with Windows XP, they use software to enforce this rule (activation). In contrast, once you have purchased Linux, you can run it on any number of computers for no additional charge.

As of January 2005, the upgrade edition of Windows XP Home Edition sells for about $100, XP Professional is about $200. The "full" version of XP Home is about $200, the full version of XP Professional is $300. Windows Server 2003 Standard Edition with 10 Client licenses is about $1,100. Because they save $100 or so on the cost of Windows, Wal-Mart can sell a Linux based computer for $200 (without a monitor) whereas their cheapest Windows XP computer is $300 (as of January 2005).

You can buy a Linux book and get the operating system included with the book for free. You can also download Linux for free from each of the Linux vendors (assuming your Internet connection is fast enough for a 600 MB file and you have a CD burner) or from http://www.linuxiso.org
.Both these options however, come without technical support.

You can purchase assorted distributions of Linux in a box with a CD and manuals and technical support for around $40 to $80 (some distributions may be less, others may be more). Regular updates and ongoing support range from $35 a year for a desktop version of Linux to $1,500 for a high-end server version. In August 2004 Red Hat started selling a desktop oriented version of Linux for under $6 per user per year.

After the initial cost (or lack thereof) of obtaining software, there is the ongoing cost of its care and feeding. In October 2002, ComputerWorld magazine quoted the chief technology architect at Merrill Lynch & Co. in New York as saying that "the cost of running Linux is typically a tenth of the cost of Unix and Microsoft alternatives." The head technician at oil company Amerada Hess manages 400 Linux servers by himself. He was quoted as saying "It takes fewer people to manage the Linux machines than Windows machines." Microsoft commissioned a study that (no surprise) found it cheaper to maintain Windows than Linux. However, one of the authors of the study accused Microsoft of stacking the deck by selecting scenarios that are more expensive to maintain on Linux.

If you are up to installing Linux yourself, you can buy a new computer without any operating system from Dell or Wal-Mart, perfect for installing your favorite flavor of Linux. Dell sells their PowerEdge servers without an OS, Wal-Mart sells some of their Microtel computers without an OS.

File Hierarchy:

Windows and Linux use different concepts for their file hierarchy. Windows uses a volume-based file hierarchy, Linux uses a unified scheme. Windows uses letters of the alphabet to represent different devices and different hard disk partitions. Under Windows, you need to know what volume (C:, D:,...) a file resides on to select it, the file's physical location is part of it's name. In Linux all directories are attached to the root directory, which is identified by a forward-slash, "/". For example, below are some second-level directories:
/bin/ ---- system binaries, user programs with normal user permissions
/sbin --- executables that need root permission
/data/ --- a user defined directory
/dev/ ---- system device tree
/etc/ ---- system configuration
/home/ --- users' subdirectories
/home/{username} akin to the Windows My Documents folder
/tmp/ ---- system temporary files
/usr/ ---- applications software
/usr/bin - executables for programs with user permission
/var/ ---- system variables
/lib --- libraries needed for installed programs to run
Every device and hard disk partition is represented in the Linux file system as a subdirectory of the lone root directory. For example, the floppy disk drive in Linux might be /etc/floppy.The root directory lives in the root partition, but other directories (and the devices they represent) can reside anywhere. Removable devices and hard disk partitions other than the root are attached (i.e., "mounted") to subdirectories in the directory tree. This is done either at system initialization or in response to a mount command.

Both support the concept of hidden files, which are files that, by default, are not shown to the user when listing files in a directory. Linux implements this with a filename that starts with a period. Windows tracks this as a file attribute in the file metadata (along with things like the last update date). In both OSs the user can over-ride the default behavior and force the system to list hidden files.

Scripting:

Windows started with BAT files (a combination of OS commands and optionally its own language) and then progressed to Windows Scripting Host (WSH) which supports two languages, JavaScript and VB Script. Linux, like all Unix variants, provides multiple scripting languages, referred to as shell scripts. In general, the Linux scripting languages are older and cruder than WSH but much more powerful than BAT files. They tend to use special characters instead of English commands and don't support objects (this only matters to programmers). One scripting language that can run on both Linux and Windows is PHP. It always has to be installed under Windows, it may have to be installed under Linux. PHP is typically found running on Linux based web servers in combination with Apache, but it is capable of running "client side" (on your computer).

User Data:

Windows allows programs to store user information (files and settings) anywhere. This makes it impossibly hard to backup user data files and settings and to switch to a new computer. In contrast, Linux stores all user data in the home directory making it much easier to migrate from an old computer to a new one. If home directories are segregated in their own partition, you can even upgrade from one version of Linux to another without having to migrate user data and settings.

Shutting Down:

Both have to be told to shut down and for the same reason, to quiesce in-flight activity in an orderly manner. You shut down Windows thru the Start button, then select Shutdown. In both the KDE and Gnome GUIs for Linux, you shut the system down by first logging out (equivalent to logging off in Windows). In Gnome, you select the Halt option, in KDE, the shutdown option. Linux can also be shut down from a command prompt using the shutdown command. The shutdown command can either shut the system down immediately or be told to shut down at some time in the future, an option not available in Windows.

Choosing Linux vs. Windows:

On the Personal Computer show in December 2003 John C. Dvorak predicted a bright future for Linux. His main points being: it's free, the applications are getting more mainstream, Open Office is a "fabulous" product, the GUI is pretty much like Windows, it's high quality, bullet proof and resistant to the thousands of Windows viruses and worms. If he owned a company with thousands of PCs, he would put everyone on Linux.