Regardless of how fast, stable, and geek-chic desktop GNU/Linux has become, we still live in a Windows world. Many vendors, either through lack of vision or funding, will produce only a Windows version of their software or drivers. If you're a gadget geek like me, you likely end up in the same old quandary of "I want that gadget, but it only has Windows drivers." If you're even more like me, you'll elect not to take the high road and search for ways to run that bad boy on your desktop GNU/Linux box.

There are a handful of products that will enable Windows applications to run on GNU/Linux, all with varying degrees of success. Regardless of which products are on the market, they'll fall into two categories: those that require you to have a licensed copy of Windows, and those that don't. Win4Lin and VMware fit into the first category, which I affectionately call "virtual machine-type" applications. The second category is where products like Wine, CrossOver Office, and Cedega fall. These products don't require Windows, rather they attempt to fool Windows applications into thinking they're running on Windows by performing varying types of tricks at the binary level. I call this class of application "windows emulators" (quite wrongly, I admit).

It only seems fair to compare apples to apples and so this article is a comparison of the two virtual machine-type applications Win4Lin 2.7 and VMware Workstation 5.5.1. The test emphasizes desktop GNU/Linux and the test platform is a suitably powerful Dell Inspiron 1000 laptop with 512MB of RAM, a 30GB hard drive, a 2.2GHz processor running Kubuntu "Breezy Badger" 5.10 with kernel 2.6.12-10-386.

Overview
While it's important to note that both Win4Lin and VMware are both virtual machine-type applications capable of running Windows on a GNU/Linux box, they differ in the extent of their functionality. Win4Lin Pro is specifically designed to run a single copy of Windows whereas VMware Workstation is designed to provide many virtual machines, each of which can run a single copy of Windows, Linux, NetWare, or Solaris x86. This extended functionality is reflected in the price and download size.

Pre-Installation
Due perhaps to the fact that I've been writing a new Linux user blog for so long, I put a great deal of emphasis on the stuff that happens before I get down to the business of installing applications. How is the Web site laid out? Is the product easy to find and download? How is the documentation and support?

The Win4Lin Web site is well laid out and I found the download page for my preferred product in a few intuitive clicks. Once on the right page, I knew that I wanted the Win4Lin Pro product, and I found both Debian and RPM packages for the latest version, but no tarball. I downloaded and installed the 3.6MB Win4Lin Pro version 2.7 file named win4linpro_6.2.7-02_i386.deb, and went about reading the online documentation to figure out how to configure it.

I had to register to get a demonstration license key, but that's to be expected.

Win4Lin requires the KQEMU accelerator module for acceptable performance. Win4Lin Pro automatically builds this module as a kernel-compatible device driver every time Win4Lin is installed or upgraded. For KQEMU to be built correctly, however, the local system has to have the kernel source on it. The Win4Lin documentation contains instructions on how to install the kernel source for Fedora, Red Hat, Debian stable, Mandriva, SuSE and, thankfully, Ubuntu 5.10. The Ubuntu 5.10 instructions walked me through activating the "Universe" repositories and gave me the commands to get the packages KQEMU needed.

The VMware site was a little tricker to navigate, but still completely usable. I had to register even to download an evaluation version, but again there's nothing wrong with a company tracking its potential customers. I was surprised to see that an enterprise-ready application like VMware only offered an RPM and tar.gz package. I guess that's indicative of the inroads that companies like Red Hat are making into the enterprise space. However, running a Debian-based distro, I had to make do with the tarball. Like Win4Lin, I needed the toolchain and kernel source to build and install VMware.

I downloaded the 95MB VMware-workstation-5.5.1-19175.tar.gz file, untarred it and ran the intuitively named VMware-install.pl file in my newly created VMware-distrib directory. The VMware installation script asks a lot of questions, but also offers a lot of common sense defaults. With the exception of having to correct its selection of network interface to bridge to, the defaults worked on my system.

Company Support
As is my custom, I generally contact a company before reviewing their product to give them the opportunity to ensure that I get the right product and have access to some support while I am doing the review.

Win4Lin completely blew VMware away in this respect. As soon as I asked for a review copy, Dan Perlman of Win4Lin was at my beck and call for the duration of my testing. I got my evaluation copy of Win4Lin within 24 hours of asking for it and follow up e-mails as time went on. I rarely waited more than a few hours to get answers to my questions. VMware, on the other hand, barely gave me the time of day.

I told VMware that I would be evaluating its product for a magazine article at the same time I told Win4Lin. VMware returned my e-mail six days later and then told me that they were going to snail mail me a copy of the application. Fifteen days later, I still didn't have it, but an e-mail with a VMware license key popped up in my inbox four days ago without any preamble or explanation of what it was for. Unfortunately, the e-mail wasn't useful because the download instructions with it didn't reflect the actual layout of the VMware Web site. As I write this it's been 21 days since I asked for a review copy and support from VMware and I've gotten neither. I can't help but wonder what would happen if I was a regular user who needed support.

Installation
Both products took the same time to install. There are really two installs with these virtual machine-type applications. The first being the installation of the application itself and the second the Windows installation in the newly minted virtual machine.

The VMware installation took 15 minutes to install once I had the toolchain. Then I installed my Dell recovery Windows XP SP1 CD in my new virtual machine, which took an hour and six minutes.

Win4Lin took 25 minutes to install, and another 60 minutes to get my trusty Windows SP1 CD installed and running.

Win4Lin put a launch icon on my desktop while VMware put itself under my Kicker -> System menu.

Performance
I put both products through their paces, but first I wanted to see how they performed out-of-the-box with simple startups and shutdowns. Table 1 shows these rudimentary metrics and how they compare against a native Windows XP Home SP2 install.

Win4Lin has a quicker launch and comparable shutdown time than VMware. When you take into consideration that Win4Lin has terminated at this point while VMware is still running - the shutdown times come even closer together.

During the test I had to reinstall both products at least once because of network interface problems. At one point VMware failed to launch complaining that it had been installed but not configured despite running fine for several days. A quick system survey showed that all of my network interfaces, including VMware's vmnet interfaces had gone AWOL. I had to re-run the VMware configuration script to get back up and running.

On another occasion, my local loopback interface (lo) failed to come up and that stopped Win4Lin dead in its tracks. Bringing it up manually restored Win4Lin for me.

I'm not convinced that either of these incidences were the fault of the products since it's not unheard of for my testing platform to exhibit unusual behavior with Linux apps from time to time. Thankfully, in both cases, my precious Windows XP images, which I had painstakingly upgraded to SP2, were still intact.

Show Time
When I'm not writing magazine articles or blogging, I produce a weekly podcast named The JaK Attack!. I use the wonderful and free Audacity audio editor to record, edit, and encode my shows. I decided to use the Windows version of Audacity to put Win4Lin and VMware through their paces. This process is a good benchmark because it's practical in a number of ways:

1. It tests the USB connectivity because I use a thumb drive to move the raw audio files around
2. It tests the sound card functionality because I need to listen to the audio to edit it
3. It tests the video responsiveness because I have to grab and drag chunks of audio around during editing, and
4. It tests CPU usage because crunching a big WAV file into a small OGG Vorbis file takes a considerable amount of memory and CPU cycles.

I thought that it might be interesting to compare not only how the two products did against each other, but also against a native Windows XP Home install. On all platforms I took a 34MB WAV file, did some rudimentary editing, and then told Audacity to encode it into an OGG Vorbis file at three different quality levels: 0, 5, and 10. The encoding process is really the only solid measurement that spans all systems, so that's what we'll look at. Table 2 shows how the three products fared.

Clearly, VMware Takes the Cake for Speed Here
Comparing products such as VMware and Win4Lin can be difficult. While most users would likely be looking at these products to host more run-of-the-mill applications than my Audacity, there's no real concrete way to measure how much faster an office product or Web browser performs one over the other. I didn't want to run a boring old benchmark application on both platforms. I wanted a real practical test that had some CPU intensity to it. Crunching audio fit the bill nicely.

The CPU metrics are only part of the evaluation; there are other areas to take into consideration.

Functionality
I was surprised to find out that neither product supported the two USB memory sticks that I regularly use on both my Windows and Linux machines. Neither my 256MB Sony MicroVault nor my Kasercorp 2.2GB Jumbo Drive were recognized by either VMware or Win4Lin despite the fact that both devices are USB 2.0-compliant. I tried hotplugging the drives while the Windows guest was running as well as inserting the drives before launching the guest systems. The drives remained silent.

Win4Lin automatically creates a "HOME on host" share folder on the guest Windows' desktop that represents the current user's home directory. This is a great little extra that VMware doesn't offer. You can certainly gain access to the host's file system in VMware, but you have to add it as a share using the VM -> Settings menu. Not hard, but not obvious, either.

Interface
Both applications provide a nearly seamless interface for mouse movement. I was able to glide my mouse around my entire desktop and manipulate objects regardless of which desktop they resided on. I was surprised by this functionality in VMware because other versions I've used required me to press control-alt to release the mouse cursor from the virtual machine back onto the host desktop.

VMware sports a tabbed interface at launch to select a guest operating system. It's well laid out but not required in Win4Lin since Win4Lin is designed to run a single instance of Windows. (See Figure 1)