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).

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 (Windows Product Activation at first, later Genuine Windows). 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).

The irony here is that Windows rose to dominance, way back when, in large part by undercutting the competition (Macs) on cost. Now Linux may do the same thing to Windows. 

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 www.linuxiso.org. Both these options however, come without technical support. All versions of the Ubuntu distribution are free. 

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. 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.

I don't know if there will ever be an objective measure of the ongoing care and feeding costs for Linux vs. Windows. If there were however, it would have to consider:

• Dealing with bugs in the operating system
• Dealing with bugs in application software
• Dealing with viruses, worms, Spyware, etc.(big advantage to Linux here)
• Dealing with software upgrades to new versions (both the OS and applications)

Note: See the next topic too.

July 9, 2008 Ubuntu Linux goes retail. You can now buy an Ubuntu Linux CD with v8.04 at Best Buy for $20 in a package that includes 60 days of technical support to help you started.

Nothing need be said about getting Windows. As for Linux, you can buy a computer with it pre-installed, but usually not at major retailers. All the major PC vendors have been selling Linux based machines on their web sites for years. In large part though, these were server computers targeted at businesses not consumers. Linux pre-installed on consumer machines has been hit or miss, mostly miss. But, there are signs that this is changing (see the next topic - low cost laptops - for more on this).

There seems to be (as of November 2007) a new trend in targeting Linux for consumers. Many different companies are offering computers with low end CPUs targeted as second machines, or for use by children. This could be a Windows Vista backlash. Moving from Windows XP to Vista requires more complexity, more hardware horsepower and learning a new interface. Plus, it's expensive both for the hardware and the software. In contrast these latest Linux based computers machines have a simplified user interface and require the same or less hardware horsepower than Windows XP. And they are much cheaper, both for hardware and software reasons. The Linux interface can be customized, and every company selling a Linux based machine customizes the look and feel. Some go for simplicity hoping the machine can be used by children and non-techies. Other try to mimic the Windows XP interface.

An interesting article on cheap Linux computers for consumers is Five reasons not to fear a $200 Linux PC by Erica Ogg of CNET dated January 24, 2008. The subtitle is: A rash of supremely affordable PCs preloaded with Linux has hit mainstream retail stores. And trying one is not as risky a proposition as you might think.

Wal-Mart was a very early player when it came to selling computers running Linux. In November 2007 they started again, after backing away from it. The Everex Green gPC TC2502 is $200 (just for the computer, no monitor), emphasizes online applications but comes with Open Office, runs a version of Linux called gOS (which itself is a version of Ubuntu v7.10) and comes with 512MB of RAM, an 80GB hard disk, a CD burner/DVD reader and both Ethernet and a modem for connecting to the Internet. According to a CNET review in also includes 24/7 toll-free tech support. Shortly after its release, it appears to be popular. See also Review of the Everex TC2502 Green gPC and $200 Ubuntu Linux PC Now Available at Wal-Mart. I have used this machine. I hated it - for the software not for the hardware.

Previously, Wal-Mart sold PCs with Lycoris, Lindows and SuSE also for as low as $200. In March 2004, they started selling Sun Microsystems' version of Linux, the Sun Java Desktop, starting at $298. In December 2004, Wal-Mart started selling a $498 laptop computer running Linspire. I don't think these were big successes.

In January 2008, Sears started selling a Linux based tower machine for $300, with a $100 rebate that brings it down to $200. The hardware is from Mirus Innovations and it comes with a Celeron processor, 80GB hard disk, 1GB ram, a CD burner and Freespire version 2.0 (a version of Linspire).

The Zonbu Desktop mini is small, silent and cheap. It is approximately 5 x 7 x inches with no moving parts, 512 MB ram, and 4GB of flash based storage. It costs $100 to $300 depending on the service plan you chose (as of January 2008). Service plans include continuous online backup. See One week with Zonbu by Peter Glaskowsky at CNET September 14, 2007.

In June 2007 Dell started selling consumer machines with Ubuntu Linux pre-installed. See Dell picks Ubuntu for Linux PCs at CNET News.com. As of December 2007 they sell machines with Ubuntu Linux version 7.10. As of July 2008, Dell was still offering Ubuntu 7.10 despite the fact that version 8.04 had been out for a couple months. Also as of July 2008, Dell also offers Red Hat and Novell Linux on various machines. See here and also dell.com/linux and linux.dell.com.

In January 2008 Shuttle introduced a $200 Linux based computer running Foresight Linux 2.0 with no optical drive, no keyboard and no mouse. See the Shuttle KPC home page. As of July 2008, a $229 model had a Celeron processor, 512MB ram and an 80GB hard disk. For $300 you got a Pentium dual-core, 1GB of ram and a 160GB hard disk. Like all Shuttles, it's small: 6.4" high, 11" long, and 7.5" wide. CNET reviewed it in May 2008.

Also in January 2008 Asus said it will release a desktop version of the Eee PC to be called the E-DT. The E-DT is expected to cost between $200 and $300 (obviously this is without a monitor).

In August 2007 Lenovo announced plans to sell laptop computers with Linux pre-installed. They ran a Linux distribution from Novell and went on sale in January 2008. I blogged about a Linux Thinkpad in May 2008. In September 2008, Lenovo backed off, they no longer offer Linux pre-installed. See Lenovo Exits pre-Installed Linux Desktop Business.

HP dipped their toe into consumer Linux, but as of June 2007, every HP consumer desktop is running Windows Vista. On their 38 consumer laptops, 37 are running Vista, one uses XP. Even their small business desktop machines are all Windows. They only sell server versions of Linux. Back in 2004 HP was planning to offer a business notebook computer, the Compaq nx5000, with SUSE Linux pre-installed.

Linux Certified sells normal laptops (that is, not the newer low end laptops such as the Asus EEE) with Linux pre-installed. In August 2008 they had three models for $700 and they also sell ThinkPad T61 models with Linux for prices from $1,300 to $1,800.

Emperor Linux loads Linux distributions on laptops from Dell, Lenovo (ThinkPad X61s), Fujitsu, Sony and others. They offer a tablet computer running Linux and the Panasonic rugged Toughbook CF-U1 with Linux.

Pogo Linux sells custom-built desktops, workstations, blades and servers loaded with your choice of seven Linux distributions.

Affordy sells the Titan line of computers with a customized version of Ubuntu, called Titan LEV, pre-installed. Desktop machines start at $218 (last checked October 2008).

ZAReason sells laptops, desktops and small form factor comptuers with Linux pre-installed. As of November 2008, their cheapest laptop was an Asus Eee PC 1000 running Ubuntu 8.10 for $599. Among their other offerings is the Shuttle KPC, also runing Ubuntu 8.10, for $210.

system76 sells laptops, desktops, netbooks and small form factor comptuers with Ubuntu pre-installed. As of April 2009, their netbook was $360, a 12 inch laptop was $740 and a 15 inch laptop was $760. Desktops ranged from $250 to $790 and came in multiple form factors.

In August 2008 Dana Blankenhorn did a series of blog postings at ZDNet about buying a Linux Laptop.

NOTE: This topic was written in January of 2008 and as of now (October 2008) it is very outdated. The Netbook market has grown and expanded immensely.

An exciting new trend is the appearance of Linux pre-installed in many new lost-cost laptop computers.

The most popular example of this is the ASUS Eee PC 4G which was released in November 2007. I have briefly used one and it's very impressive. Prices range from $300 to $500 (as of January 2008). The $300 model strikes me as a huge bargain, even if the screen is a bit too small.

The $200 XO laptop from the One Laptop Per Child Foundation has gotten much publicity. I used one and hated it. That said, it is targeted at children in developing countries and being an adult living in New York, I'm not the target audience. As far as I can tell you can't buy one anyway (as of January 2008).

Everex started selling their small Linux laptop, called the CloudBook, in February 2008 for $400. It is being sold at Wal-Mart, Newegg and TigerDirect, and ZaReason.com. It seems to compete directly with the Asus EEE laptop. See Engadget and Gizmodo. It has a 7" 800 x 480 display, 512MB of ram, a 30GB traditional (not flash) hard drive, Wi-Fi, Ethernet, a 4-in-1 card reader, a webcam and an Ubuntu-based version of Linux called gOS. It will weigh two pounds and the size is approximately 9" x 7" x 1".

Intel makes the Classmate PC. Quoting Intel they are "mobile personal learning devices for primary students (ages 5-14) in emerging markets." The Classmate was never intended for sale to the general public. I've read that this was out of fear by Intel that low cost Linux laptops would cut into their profit margins. As far as I can tell, they are not being sold in the United States. The Classmate uses many of the same parts as the Asus EEE laptop. It has a 7" screen with an 800x480 resolution, a Celeron processor, WiFi and 2GB of flash based hard disk storage.

Zonbu offers a laptop but it is a full size machine with a 15.4" wide screen and a built-in DVD-ROM/CD-RW. As of January 2008, it sells for $280 to $480 depending on the service plan.

If I had to bet, I'd say that low cost Linux laptops will take off. The cost, simplicity and portability are likely to be the big appeal. Not to mention immunity from most malicious software and the lack of a normal disk that increases the battery life and makes the machine more rugged. Linux can only run a handful of Windows programs, but out of the box these machines (except the XO) can do what most people need most of the time. I've read that Intel is working on a new processor called Silverthorne (for now) that will be cheap and engergy efficient and may spurn more cheap Linux laptops to appear on the market.

There are three ways to install Windows XP: a clean install, an upgrade install and a repair install. Then, there is a "recovery" install, which is not an install in the true sense of the word but rather the restoration of a disk image backup.

• A clean install refers to starting with nothing (either an entirely empty hard disk or just an empty partition or just unallocated space on the hard disk) and ending up with just Windows.
• An upgrade install refers to starting with an older version of Windows and ending up with a newer version. Existing data files and applications should not be affected by the upgrade to the newer edition of Windows.
• A repair install refers to installing the same version of Windows on top of itself. This is used to fix a broken copy of Windows and existing data files and applications are not affected.
• A "recovery" is typically used to restore a computer to its factory fresh state. All data files are wiped out. All applications installed since the computer was new, are wiped out. All upgrades to Windows itself (patches, service packs) are lost. Applications pre-installed by the computer manufacturer are restored. Originally this was done from CDs, then DVDs. Now it is normally done from a hidden area of the hard disk.

Then there is Windows Vista where much has changed. I'm not familiar with the install options for Vista. Andy Pennell, a Microsoft employee, wrote about his problems installing Vista on June 21, 2007. He is very familiar with Windows and installed Vista onto a second internal hard disk, leaving the existing hard disk with Windows XP unchanged. At least that was the plan. See Installing Vista: My Personal Hell. Installing Vista on a computer with an existing copy of Windows, with the intention of dual-booting, is much trickier than it used to be with earlier versions of Windows.

There is a huge variation in the Linux installation procedure. Different distributions of Linux have their own installation programs (which may even change with different versions of the same distribution). Installing Linux on a computer without an existing operating system is much easier than installing it on a machine with an existing OS that you want to preserve.

I'm sure that installing Linux is getting easier all the time. While I haven't done it all that often, I have seen it become easier over time. Is it easy enough for you?

• Ed Bott blogged about his experience installing Linux on July 31, 2006. Linux, XP, and my old PC
• In March 2007, he tried again with mixed success. Why does Linux hate me?
• A picture is worth a thousand words so this July 2007 picture show at ZDnet on Installing OpenSUSE 10.2 is instructive
• In June 2007, I installed Ubuntu v7.4 on an IBM NetVista machine that was about four years old. The system would only run at 640x480 and things went downhill from there. The problem may have been due to a KVM switch that prevented the system from querying the monitor. However, instead of asking me or telling me anything about a failure to detect the monitor, it just ran at 640x480 with no GUI based facility to increase the resolution.

When installing Linux on a machine where you don't need to preserve the existing operating system, there is likely to be an option to clobber the existing OS as part of the Linux installation procedure. Or, you can use a program to totally wipe everything off the hard disk before installing Linux. The free Darik's Boot and Nuke is fairly famous for this. Better yet, the hard disk vendor should have a free utility that not only wipes the hard disk but also can run diagnostics on the disk.

You can also buy a new computer without any operating system. A low end Dell server, the PowerEdge 840 sold for $600 in June 2007. You can buy an HP ProLiant server starting at $500 that is certified to run six Linux distributions. IBM is big on Linux, quoting their web site: "The entire IBM Systems product line is Linux enabled." They sell computers both with no operating system and with Linux pre-installed. Nothing there is cheap however. Wal-Mart used to sell Microtel machines without an OS, but no more.

Installing Linux for dual booting, that is, keeping the existing operating system in tact, is probably best left to techies. It is all too easy to lose the pre-existing OS. You need to be familiar with hard disk partitions and some Linux terminology. With Red Hat Linux 8, the booklet on how to install the OS was over a hundred pages.

In his Linux book, Mark Minasi said that installing Linux on a desktop computer was more likely to be successful than on a laptop computer.

Added November 23, 2008: ZAReason sells a bootable copy of Ubuntu on a 4GB USB flash drive for $39.99. In general new computers can boot from a USB flash drive, however older computers may not be able to. According to the company, the drive is configured to support persistence, but it is not the default option. That is, by default it functions like a Live CD and throws away all record of your actions. However, at bootup you can select persistence if you want. That said, the company noted in an email that versions of Ubuntu prior to Intreped were "somewhat buggy with persistence".

Added July 10, 2008: From my CNET blog Why you want a Linux Live CD.

One thing that Linux can do that Windows can not, is run from a CD. To run Windows, it has to first be installed to your hard disk. Normally Linux also runs from a hard disk, but there are quite a few versions of Linux that run completely from a CD without having to be installed to a hard disk. The term for this is a "Live" CD.

Running a Live CD version of Linux is a great way for Windows users to experience Linux for the first time. Among the Linux distros that have a CD-only version are Knoppix, Ubuntu and Open SuSE). I tried SuSE Live Eval version 9 in October 2003 and had some gripes. FreeBSD, a version of Unix (rather than Linux), also has a LiveCD.

That said, if Windows is broken to the point that it can't start up, there is a free program called Bart's Preinstalled Environment (BartPE) that can run a few Windows programs from a bootable CD. However, this is not from Microsoft and is only intended to fix a broken copy of Windows, it is not for everyday use. BartPE can only run a handful of programs that have been set up ahead of time for use with it. BartPE fills an important need, but creating the CD is not trivial, it requires a Windows CD (not recovery CDs or DVDs) and it only works with Windows XP and 2003 (not sure about Vista). The main point stands, in and of itself, Windows can not run from a CD.

The CD based versions of Linux differ in their use of the hard disk. Some, such as Lindows, do not write anything at all to your hard disk, making it the safest and easiest way to experience Linux. The downside of this is speed (CDs are much slower than hard disks) and continuity (being able to save data between uses). Other versions, such as SuSE 9 (this is now up to v10.2), do use your hard disk (SuSE 9 creates over 200 MB worth of files). What you give up in safety, you gain in speed. For reviews of Linux distributions that run from a CD see A Taste of Linux by Jim Lynch at ExtremeTech January 23, 2004 and A Taste of Linux, Part Two by Jim Lynch March 5, 2004.

In addition to kicking the tires on Linux, a Live CD can also be used to insure that your hardware is supported by that specific version of Linux. Bootable Linux CDs are also used to recover files when Windows breaks to the point of not being able to start up. A recent Live Linux CD should be able to see all Windows files (they can read NTFS) and copy them to an external USB device or another computer on a LAN. Older CD based versions of Lindows and SuSE could not read files stored in an NTFS partition.

In October 2005 a whole new way of running Linux without installing it was introduced: Virtual Machines from VMware. Virtual machines let you run multiple operating systems on one computer at the same time. You can't beat it (virtual machines are used to run Windows on the Intel based Macs).

Using the free VMware Player you can download pre-built Linux virtual machines. Think of the VMware Player as analogous to the Adobe Acrobat Reader. Creating virtual machines costs money, but playing them does not.

VMware has been creating virtual machines on PCs for a long time. Running a virtual machine previously required their expensive software (VMWare Workstation was $200 in April 2007, only a couple years previously it cost almost twice that). Now it can be done for free. And prior to October 2005 there were no pre-built virtual machines available from VMWare, if you wanted to run Linux, you had to install it.

Now you can get a pre-installed virtual copy of Ubuntu v7.04 Server, OpenBSD 4.0 and CentOS 5.0. Even better, many pre-built Linux virtual machines come with pre-installed applications. Want to run the Apache web server and the MySQL database? Just download a VM with them installed.

For years you could have installed Linux into a new virtual machine. It is a great way to learn and experiment. However, creating a new virtual virtual machine required the somewhat expensive VMWare workstation. Now, the free VMware Server software can be used to create a new virtual machine into which you can install any operating system. You can also download new, empty virtual machines from EasyVMX.

VMWare Server has another big plus: it supports a checkpoint (a.k.a. restore point, synch point). You can take a checkpoint in your virtual machine, work on it a while and then revert the VM back to the checkpoint. All for free. How things change.

Microsoft also has free virtual machine software but there are no-prebuilt virtual machines for it. Needless to say, Microsoft is not going to provide Linux virtual machines and they make a lot of money selling Windows so they're not going to give it away. Also, their software is not as mature as VMware, not as robust and I've read that it runs slower.

VMware is not the only free virtual machine software. VirtualBox is free and open source.

Yet another way to run Linux without installing it is from a flash drive (a.k.a thumb drive, USB drive, pen drive, memory stick, etc.).

In June 2006 David Pogue wrote about Linux distros can run from a thumb drive (A Handy Tip From a Reader on Flash Drives) where the two distros mentioned are 50MB (Damn Small Linux) and 70MB. In fact, Damn Small Linux does even more tricks. It can run from within Windows! And, if you have 128MB of ram to spare, it can run completely in ram, which has got to be fast. See Linux in Windows .. Again at ghacks.net.

In November 2005, you could have purchased a 3GB MicroDrive (1 inch hard disk) with Ubuntu Linux. The drive plugs into a USB port and is fully powered by the USB port. See Taking Linux On The Road With Ubuntu at Toms Hardware. I'm not sure if this is still available.

And work is ongoing on creating portable Linux applications (as of March 2007).

There is more application software available for Windows. Then again, there may be sufficient Linux software for your needs.

Obtaining application software: If you buy a copy of Windows on a CD-ROM, you get no application software with it. If you buy a copy of Linux on a CD-ROM (or two or three) it typically comes with gobs of free application software. Likewise, Linux ISO downloads usually include lots of application software. The exception are Linux distributions that are small on purpose such as Damn Small Linux or Pen Drive Linux.

A new computer with Windows pre-installed normally comes additional application software, exactly what to include is up to the PC vendor. On one extreme, I have seen a new Sharp laptop machine that came with no software other than Windows itself. This is rare. In contrast, Sony VAIOs, for example, are more mainstream and come with a lot of software. However, there are two problems with the pre-installed application software on Windows computers.

First, much of it is junk. So much, that a new term "crapware" is being used to describe it. The PC vendors make money by installing this software that many people consider worse than useless. In fact, the first thing many techies do is un-install this software, someone even came out with a PC de-crapifier program to automate the un-installs. Windows computers sold to businesses tend to have less undesirable application software pre-installed compared to computers sold to consumers. I have never heard of anyone complaining about the software that comes pre-installed in the normal, popular versions of Linux.

Second, important software is often missing or old. For example, the Adobe Acrobat reader, may not pre-installed by the PC vendor. In February 2008, I blogged about a new Lenovo computer that came with terribly old versions of application software.

On the Linux side, to get a feel for the application software that comes with Ubuntu version 8.04 see Adventures with open source apps on Linux - Part 1 by Adrian Kingsley-Hughes from May 23rd, 2008.

Application software installation: The installation of applications under Windows, while not standardized, is generally consistent and generally pretty easy. Installing software under Linux varies with each distribution and has not been nearly as simple, easy or obvious as Windows. A couple articles from 2004 griped about how hard it was to install software in Liunx: The May 20, 2004 issue of the Langa list newsletter and a July 4, 2004 review of Linux in the Washington Post (Linux, Still an Awkward Alternative) where Rob Pegoraro called application software installation "Linux's biggest embarrassment".

That said, current Linux distributions have an application somewhat akin to Windows update that can be used to install software. I don't have much experience doing this. However, in April 2008 I used one of the new $200 Walmart Linux gOS machines and found the application for installing software very confusing, and it failed every time I tried to install something.

A program written for Linux will not run under Windows and vice versa.

For example, Microsoft makes a version of Office for Windows and another version for the Mac. They are two different products, each capable of only running on the operating system it was designed for. There is no version of Microsoft Office for Linux.

On the other hand, some programs, such as Firefox, are available for multiple operating systems. Firefox runs on Linux, Windows, Macs and more. Open Office competes with Microsoft Office and comes in versions for Windows (all the way from Windows 98 up to Vista), GNU/Linux ("Linux"), Sun Solaris, Mac OS X (under X11), and FreeBSD.

The process of making a new version of a program that will run on a different operating system is called "porting". But there are other ways to get a program to run on an operating system other than the one it was designed for.

Virtual Machines

The most ambitious approach is to install one operating system inside another. Perhaps the most popular example of this is with Intel based Macintosh computers. Software from Parallels (Parallels Desktop 3.0 for Mac) and from VMware (Fusion) lets you run Windows at the same time as Mac OS X. In this example, the Mac OS X is referred to as the host or native operating system, it's the one that gets run when the computer is turned on. Windows is referred to as the guest operating system. This approach is called Virtual Machines. Assorted virtual machine software is available that lets Linux, Macs and Windows operate as either the host or guest operating system.

In a guest copy of Windows, running under either Linux or Mac OS X as the host OS, you can install any and all Windows programs. Somewhat like a split personality, one computer can run two (or more) operating systems at the same time. VMware was the first to market with a virtual machine product (also called VMware) for personal computers. Virtual PC, has competed with VMware for a long time. Parallels is a more recent competitor. VirtualBox is free and open source virtual machine software. Virtual Machine products from these companies differ in their supported host and guest operating systems.

Win4Lin is virtual machine software that only supports Linux as the host OS and only supports Windows (95, 98, Me, 2000 or XP) as the guest OS.

Specific Applications

Less ambitious than virtual machine products (which let you run any application in the guest OS) are approaches targeted at only running a handful of Windows applications under Linux.

The simplest example is probably IEs 4 Linux which lets you run Internet Explorer versions 6 and 5 under Linux. It's free. For more, see Run Internet Explorer on Linux by Brian Smith Oct 11, 2007.

Some distributions of Linux include commercial software called Crossover Office from CodeWeavers that runs Microsoft Office (versions 2003, XP, 2000 and 97) and some other Windows applications under Linux. While this approach does less, it does not require a Windows license. Codeweavers has a list of supported applications and a comparison of their approach vs. virtual machines.

Since Crossover Office is a commercial product, it is not included in the free distributions of Linux. As of October 2007 CodeWeavers sold it for $40 or $70 depending on the version.

CrossOver is based on the Wine project. Wine is free software and is included with many GNU/Linux distributions. After 15 years of development, the first "finished" version of Wine was released in June 2008 (see Run Windows Software on Linux with Wine 1.0). Wine is, to a computer nerd, very interesting. It lets Windows applications run under Linux without a copy of Windows and without any virtualization. Windows applications talk to Windows using a specification known as the Windows API. Wine intercepts each Windows API command/request made by a Windows program and does, in Linux, the functions Windows does in response to the same command.

Wine does not, and will not, provide 100% compatibility; it will never run all Windows applications perfectly. Even applications that it runs well, may not have all their features and functions available. The Wine Project maintains a list of applications and how well they run under Wine. LifeHacker did a good intro to Wine in June 2008: Run Windows Apps in Linux with Wine 1.0.

Mary Jo Foley wrote that the Microsoft WGA (Windows Genuine Advantage) program looks for Windows programs running with Wine and purposely generates an error. See Microsoft Seeks to Bottle Up Open Source Wine (February 18, 2005).

As far as I know, the first Linux distribution that could run Windows applications was Lindows. As far back as October 2002, Xandros Linux Desktop v1.0 (previously Corel Linux) could run Windows applications. (ExtremeTech review). When SuSE Linux Office Desktop was released in January 2003, it too could run Microsoft Office applications thanks to Crossover Office.

TransGaming makes WineX which allows Linux users to run various Windows games that require OpenGL and DirectX. The combination of CrossOver Office and WineX should let you run many Windows programs under Linux. In July 2004 TransGaming gave WineX a new name, Cedega, and announced support some DirectX 9 games. (Linux Takes on Windows Gaming from ExtremeTech July 28, 2004)

On yet another front, Ximian (owned by Novell) is developing Project Mono, which will allow Microsoft .Net applications to run on Linux.

On still another front, Adobe Air lets you run the same application on multiple Operating Systems.

Interesting article on whether running Windows applications under Linux is a good idea: GNU/Linux Desktop: The Case Against Running Windows Apps by Bruce Byfield February 26, 2008.

Server Based Applications

There is yet another approach to crossing the operating system divide that goes by the names Terminal Services, Server Based Computing and Thin Client Computing. This approach runs applications on a server and sends a picture of the output to another (client) computer. From the client computer, keystrokes and mouse movements are sent back to the server. This approach is totally dependent on a network.

Windows applications are run by a server version of Windows and use the Terminal Services feature to communicate with a client computer. Depending on the software used, the client computer may be running Linux or Windows or a Mac. The all Microsoft solution can be supplemented with software from other companies (Citrix being the market leader) to provide advanced features. Years back, I used an earlier version of the Citrix software, then known as WinFrame, to provide Windows NT applications to client computers running Windows 95 and 98. Quite cool.

On the Linux/Unix side, Tarantella supports the display of Unix server applications on non-Unix, non-Linux machines.

The vast majority of malicious software (of all types) runs on Windows. I don't know the actual percentages, but it wouldn't surprise me if it was 98% or so. Windows users are burdened with the need for anti-virus and anti-spyware software. Linux users are not. Why is this?

In Linux vs. Windows: Which is Most Secure? (March 2007) Kenneth van Wyk writes:

Linux [has] ... the notion of an administrative (root) user that maintains and operates the system, and desktop users who only run the software on the system, is completely ingrained in most Linux distributions. Now it’s true that many Linux users ignore these features and run all their software from a root-level account anyway, but that’s a choice that they’ve made. The system defaults to protecting the operating system components from its user’s actions (intentional or otherwise). That feature alone must account in large degree for the dearth of viruses and other malicious vermin on Linux and UNIX platforms. Windows, on the other hand, started life as a single user system, with that single user being all-powerful. Although that’s no longer the case, the general attitude can still be found in many Windows-based software products – many of which just can’t be installed and/or run properly without desktop administrator privileges. This is all changing for the better, but it took Microsoft far too long to adopt this default-secure configuration practice.

In November 2008 I purchased an Asus Eee PC 1000 which came with a modified version of Xandros Linux. Surprisingly it also came with a version of the NOD32 antivirus program from Eset.

Both Linux and Windows 2000/XP require a userid and password and boot time. That said, Windows XP supports users without a password (a very bad idea), I'm not sure if Linux does.

Windows can be configured to either ask for the userid/password at startup time or a default can be set instead. In Windows 2000 it is very easy to set a default userid/password, in Windows XP the method varies between the Home and Pro versions - in one it is straightforward, in the other it's a pain.

I've been told that in Linux the KDM and GDM login managers support automatic login. I've also been told that most versions of Linux do not allow the root user to login automatically. Windows, in contrast, is happy to let an Administrative user auto-login. Get started faster in Ubuntu explains how to configure Ubuntu to boot without asking for a userid/password.

A new Windows XP machine used by a home user is likely to not ask for a userid/password at start-up. However, this depends on the number of users defined to Windows. When you create a new user in XP the default is not to require a password (user friendly triumphs over security - the Microsoft way). Windows 98, never mind.

Windows XP, 2000 and Linux all support different types or classes of users. Windows XP Home Edition supports Administrator class users that have full and total access to the system and restricted users that, among other restrictions, can't install software. Windows XP Pro and Windows 2000 support additional levels of users.

Both Linux and Windows can group users into groups (finally, something well named) and assign privileges to the group rather than to each individual user. Windows XP and 2000 come with some pre-defined user groups (such as Power Users), I don't think Linux does (but I'm not sure). In XP and 2000 user "Administrator" is a member of the Administrators group.

Linux privileges are basically whether you can read, modify or execute a file. Files in Linux are always owned by a specific user and group. Windows has similar file-related privileges but only when using the NTFS file system. The earlier FAT and FAT32 file systems had no file level security.

I'm told that Windows NTFS permissions are a bit more functional than those in Linux, but that Linux distributions are starting to use extended Access Control Lists as a part of the file system, bringing them more on par with NTFS. (I won't swear by this)

Very often Windows users use an Administrator class userid which gives viruses total access to their system (see Why you should not run your computer as an administrator from Microsoft). This obviates the security rules discussed above. In contrast, Linux users often run as regular non-root users which not only means better security it also means that, if they get a virus, the operating system greatly restricts what the virus can do.

I have tried a couple times to set up a Windows XP computer for use by a family, creating Administrator class userids for the parents and restricted userids for children. Both cases failed because there were too many programs that did not function correctly when run by a restricted Windows user (more details here). While Linux has supported the concept of root and restricted users from the get-go, this is a relatively new thing to Windows. It will be a long time before all Windows software is designed to be used by a restricted user. Until then, viruses and malware will have free reign on Windows machines. Certainly software written for Windows 95, 98 and Me expects total system access and may not work when run from a restricted userid.

See also Windows v Linux security: the real facts by John Lettice October 22, 2004 in The Register
            Security Report: Windows vs Linux by Nicholas Petreley October 22, 2004

A swap file (a.k.a. page file) is used by the Operating System when the demands on RAM exceed the available capacity. Windows uses a hidden file for its swap file. By default, this file resides in the same partition as the OS, although you can put it in another partition, after Windows is installed. In Windows XP, the swap file resides initially on the C disk as a file called pagefile.sys. Linux likes to use a dedicated partition for its swap file, however advanced users can opt to implement the swap file as a file in the same partition as the OS. I'm not sure if this issue is clearly presented and explained when installing Linux. Probably not. Xandros v4, for example, may use a separate swap partition or not, depending on the partition environment it finds at install time. Xandros 4 does not explain any of this.

Updated August 2006: With Windows XP the default size of the swap file is 1.5 times the amount of RAM in the machine at the time Windows was installed. I don't know how Linux chooses a default swap file size. In Windows XP you can change the swap file size and location with Control Panel -> System Properties -> Advanced tab -> Performance Settings -> Advanced tab again -> Change button, which opens the Virtual Memory window. Be aware that this window violates user interface standards. It is the only window I know of where clicking the OK button after making a change, does not activate the change. To change the size of the page/swap file, you must click the Set button. I don't know how to change the size of a Linux swap file.

Windows uses FAT12, FAT16, FAT32 and/or NTFS with NTFS almost always being the best choice. The FATx file systems are older and have assorted limitations on file and partition size that make them problematical in the current environment. Linux also has a number of its own native file systems. The default file system for Linux used to be ext2, now it is typically ext3. Other supported file systems includes XFS, JFS, JFFS and Reiser3. Reiser4 is in development.
(Added December 2008: The ext3 file system is being replaced by ext4. Among the improvements in ext4 is an increase in the maximum filesystem size from 16 terabytes in ext3 to one exabyte. The largest file in ext3 is 2 terabytes, in ext4 it is 16 terabytes. OpenSolaris includes ZFS which seems like a drastic change in file system design.

File systems can be either journaled or not. Non-journaled systems are subject to problems when stopped abruptly. All the FAT variants and ext2 are non-journaled. After a crash, they should be examined by their respective health check utilities (Scan Disk or Check Disk or fsck). In contrast, when a journaled file system is stopped abruptly, recovery is automatic at the next reboot. NTFS is journaled. Linux supports several journaled file systems: ext3, ext4, reiserfs and jfs.

All the file systems use directories and subdirectories. Windows separates directories with a back slash, Linux uses a normal forward slash. Windows file names are not case sensitive. Linux file names are. For example "abc" and " aBC" are different files in Linux, whereas in Windows it would refer to the same file. Case sensitivity has been a problem for this very web page, the name of which is " Linux.vs.Windows.html". At times, people have tried to get to this page using " linux.vs.windows.html" (all lower case) which resulted in a Page Not Found error. Eventually, I created a new web page with the name in all lower case and this new page simply re-directs you to the real page, the one you are reading now (with a capital L and W).

Fragmentation: (Added January 2008) Windows file systems all suffer from fragmentation, which results in a file being scattered all over the hard disk. I'm told that Linux file systems are much less prone to this, but I don't know the details and whether it applies to all or some of the Linux file systems. With classic magnetic platter based hard disks, fragmentation can be a big deal as the disk is much slower than the RAM or CPU and having to walk all over the hard disk to get a file slows things down. How this will play out on newer SSDs I don't know. While there is no waiting for spinning platters, SSDs have to deal with wear leveling, a feature designed to extend their limited lifespan. Speaking of fragmentation, I've heard very good things about Raxco's PerfectDisk for Windows.

Crossing Over: (Last Updated: June 2007) As for supporting each others file systems, Linux can read/write FAT16 and FAT32. When I first wrote this topic, only some Linux distributions could read NTFS partitions. Now more can both read and update NTFS, a feature critical to using Linux as a Rescue CD for a broken copy of Windows.

Captive-NTFS was "the first free NTFS read/write filesystem for GNU/Linux". It is no longer being maintained. In its place is the NTFS-3G Read/Write Driver which the website describes as "an open source, freely available read/write NTFS driver for Linux, FreeBSD, OS X, and NetBSD." NTFS-3G is fairly new, being considered stable only since February 2007. It can deal with the multiple versions of NTFS used by Windows XP, Windows Server 2003, Windows 2000 and Windows Vista. At least 85 distributions support NTFS-3G in some manner, among them: Ubuntu, Red Hat, Debian, Knoppix and Mandriva.

In September 2005, PC Magazine reviewed a product called NTFS for Linux from the Paragon Software Group that gives Linux read/write access to NTFS partitions. For more information on Linux and NTFS, see the Linux NTFS Project.

On its own, Windows can not read partitions formatted with any Linux file system. However, a number of products (I haven't tried any of them) enable this:

• Explore2fs by John Newbigin can be used to read Linux ext2 and ext3 partitions.   Portable version
• Ext2Fsd claims to be an Ext2 File System Driver for Windows 
• An open source project, the Ext2 File System Driver for Windows
• The free Linux Reader for Windows from Diskinternals can read the Ext2/Ext3 file systems (added September 2007) Portable version
• The Ext2 Installable File System For Windows is free and provides full read and write access to partitions and floppy disks formatted with either Ext2 or Ext3. It works with Windows NT4, 2000, XP, Server 2003, Vista and Server 2008 (last checked July 2009). It's also referred to as Ext2 IFS for Windows. If you are running a NAS device, it may very well be storing files using the Ext2 or Ext3 file system.

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.

There are no standards in Linux for which subdirectories are used for which devices. This contrasts with Windows where the A disk is always the floppy drive and the C disk is almost always the boot partition.

Hidden Files: 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.

Case: Case sensitivity is the same with commands as with file names. When entering commands in a DOS/command window under any version of Windows, "dir" is the same as "DIR". In Linux "dir" is a different command than "DIR".

Both Windows and Linux have desktop shortcuts to applications. Linux even has the equivalent of the quick launch toolbar, a favorite feature of mine. In Ubuntu, add a shortcut to the panel at the top of the screen with: right-click an empty area of the panel, choose Add to Panel, select the program you want to add, click the Add button.(added March 2008)

According to ComputerWorld blogger Steven J. Vaughan-Nichols, "Linux needs to do a much better job of managing power. With more and more of us doing our work on laptops, netbooks, and the like, getting the most out of battery life is becoming increasingly important... To really get the most from a battery requires power-aware device drivers, power-aware applications and fine granular control over each component in a system. Linux has miles to go before it can equal Macs or even Windows in this area." (added August 11, 2008)

Updating Software (Created: July 2008, Last Updated: January 2009)

This is a big topic that I should have added long ago. I haven't used Linux enough to form my own an opinion on this from the Linux side, so I present the opinions of others. In Windows, while each program has its own custom built installation procedure they very often follow the same pattern. In Linux, each program is installed in a standard way, but there are way too many standards. The software that installs everything in Linux is called a package manager.

There are way too many package managers. Ubuntu Linux, for example, has three. What's the difference between them? Ubuntu offers no help. The Advanced Packaging Tool (apt-get) is used by Debian, Ubuntu, gOS, Linux Mint and Knoppix. YUM is used by Fedora and CentOS. OpenSUSE uses YaST. Gentoo uses Portage. Mandriva uses urpmi. and there's also Synaptic and PackageKit.

From the January 2009 article A Beginner's Guide on How to Install Linux Software: "There are several different types of installation files for Ubuntu, and few of them are as easy to install as the EXE installation files found on Windows. If you need to download an application to your system that is not found in Add/Remove Applications, then you will find yourself with one of several different types of files: .deb, .rpm, .bin, .tar.gz, INSTALL, .sh, etc. These different files all have a different method of execution." The article explains how to deal with these types of files to install software.

Computerworld blogger Steven J. Vaughan-Nichols is pro-Linux. Yet, he admits that new Linux users will be thrown for a loop when they first try to install software. In February 2009 he said "When we live with any technology, we start taking for granted knowledge that we have that's a foreign language to others. So, while package manager programs ... make installing software easy, they don't give new Linux users much of a clue what it is they're installing." He also wrote Linux software installation myths in November 2008.

Jack Wallen is a Linux enthusiast who wrote the following in September 2008: "With Linux you have (with nearly every distribution) a centralized location where you can search for, add or remove software. I'm talking about package management systems, such as Synaptic. With Synaptic, you can open up one tool, search for an application (or group of applications), and install that application without having to do any web searching (or purchasing). Windows has nothing like this. With Windows, you must know where to find the software you want to install ... For many years, it was thought that installing applications on Windows was far easier than on Linux. And for many years, that thought was right on target. Not so much now. Installation under Linux is simple, painless and centralized."

Ed Bott is a Windows enthusiast. In July 2008 he wrote about this: Windows Update vs. Ubuntu Update.

This is a summary of an article by Dan Martin called Things I can do in Linux that I can't do on Windows from March 3, 2007. (added September 2007)

The first item on his list strikes me as very important - you can update "every single piece of software on my system with a single action." Windows and Microsoft Update only do a handful of Microsoft applications. With Linux, the OS updater application handles software from other companies too. Huge plus for Linux. Huge.

An interesting point was the ability to "Run Internet Explorer 5.0, 5.5, 6.0, and 7.0 on the same desktop" using software called IEs4Linux. Other points included the fact that most updates don't require a re-boot, Linux has a lesser need for anti-malware software and the ability to take "settings" with you when traveling.

Overall, Mr. Martin is very biased. For example, with portable applications, Windows users can carry entire applications with them with traveling. He also brags that Linux users can understand everything going on inside their computer, but, he doesn't offer software for doing this. Windows users have the excellent Process Explorer program which shows tons of information about what's going on under the hood. Process Explorer is a great program. Finally, some items on his list strike me as un-important.

March 10, 2008: Here's another Linux only thing, the ability to keep an application's window on top of other windows. From CNET blogger Dennis O'Reilly: "A nice feature of Ubuntu that Windows lacks (unless you tweak the Registry or download a separate always-on-top utility) is the ability to keep a window on top of all others. Just right-click the bar along the top of the window, and select Always on Top from the drop-down menu." According to reader comments this is really a GNOME thing, rather than an Ubuntu thing.

(These three paragraphs added May 1, 2007) When this page was created XP was the current version of Windows. Now it is Vista. I mention this because many people find the Vista experience stinks. It is expensive, buggy, slow and suffers from both hardware and software incompatibilities. There seems to be a growing backlash against Vista, which is changing this topic of choosing Linux vs. Windows.

Some Windows people (the smart ones in my opinion) are opting to stick with XP and avoid Vista. Dell initially converted all their new consumer machines from XP to Vista, although they and others always sold business targeted machines with XP. Responding to consumer demand (businesses were not going to use Vista for a long time anyway), Dell backtracked in April 2007 and re-introduced new consumer machines with XP pre-installed. Heresy. Microsoft could not have been happy.

And then ... along came Linux. In May 2007 Dell announced they would start to offer consumer machines with Ubuntu Linux vesion 7.04 pre-installed. You have to wonder if Vista is driving people to Linux. Oh, and Michael Dell runs Ubuntu Linux on a computer at his home (April 18, 2007).

Martin Ultima, the person behind the Ultima Linux distribution, does not see a future for Linux on desktop computers. His reasons: video drivers are too hard to set up, many distributions omit Flash, a working media player, 3D graphics and some fonts, there are too many distributions, software development on Linux is "painful", poor support for WiFi, printers and other hardware, and poor OS documentation. He also points out the 12 years after Windows introduced CD auto-mounting, it is just starting to appear in mainstream Linux distributions. (paragraph added July 20, 2007)

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.

To date the only organizations (that I've heard about) using hundreds or thousands of Linux based computers are government agencies in countries all over the world. They may be driven by cost and/or security concerns (practically speaking there are no Linux viruses). Some countries also may not like being beholden to a U.S. based company for so much of their software.

See More Balls Through Windows from The Economist April 20, 2004 on cfo.com. Is Microsoft finally about to face real competition in desktop-computer software? This article raises a point I agree with. The next version of Windows, the one that will replace XP, is not going to be delivered for a long time opening up a window of opportunity for Linux. In addition, the upcoming version of Windows is likely to be expensive and require new hardware, two other areas where Linux competes well. It may also involve too many changes. By the time it's delivered, more and more Linux distributions will look more like Windows, just as Microsoft rolls out a new user interface. People accustomed to the current Windows UI may resist the change.

However, Microsoft fights the spread of Linux at all costs. For example, when Thailand was going to make government subsidized Linux based computers available throughout the country, Microsoft cut a deal with the Thai Information, Communication and Technology Ministry. People in Thailand can buy Windows XP and Office XP (without Outlook) pre-installed, activated, and ready to run for the equivalent of $37 US dollars. See Microsoft offers cut-rate Windows from CNET News.com February 9, 2004. Then again, the governments of China, Japan and South Korea are teaming up to create their own Asian flavor of Linux.

The above are facts, to the best of my knowledge, not opinion.
This is opinion.

Will Linux spread to the point of becoming a serious competitor to Windows on the desktop? No. And this has nothing to do with which is better, no matter how you judge "better".

Consider the keyboard in front of you. The key arrangement was made long ago when keeping the metal wires connected to the keys from hitting each other was the big consideration. Now that that no longer applies, does anybody switch over to a keyboard with a better design? No. All of us who know how to type, are used to the current arrangement of keys. Switching to a new layout would be a major disruption and thus have to pay back in a major way. I don't think desktop versions of Linux will pay back enough to encourage people to switch. My Linux experience is not extensive, but coming to it with a Windows background, as most people will, it is often frustrating to figure out how to do ordinary everyday things.

Servers are another story. So too are call centers and other single-use environments where Linux makes a lot of sense.