Jul 042008

Since Apple began using Intel processors in their computers, many Windows users have switched to the Apple platform. For those that have Windows based software and need to run Microsoft Windows, there are two options for running Windows on an Apple computer:

  1. Boot Camp — Runs Windows natively on the Apple computer but requires restarting the computer to switch between operating systems.
  2. Virtualization — Simulates PC hardware and allows Windows to run in a “virtual” environment simultaneously with OS X.

I prefer virtualization software, as it allows me to share data between applications on both platforms. Backup and recovery of virtual machine images is simple, and allows for seamless transfer of Windows environments to new equipment.

Of the virtualization options currently available for OS X, the two most popular are Parallels, and VMware Fusion. Since Parallels was the first to market in early 2006, this is the software that I have used on a daily basis. When VMware Fusion released the first non-Beta version, I downloaded and installed the trial. After transferring my Windows virtual machine (VM) from Parallels to Fusion, I found the interface to be cumbersome and the software did not seem to perform as well as Parallels. (I have not tried Fusion since the initial release, so I have no information about enhancements to later builds.) After two years of daily use, I am now proficient in the use of Parallels, and have made some observations that I believe Parallels users should be aware of.

First, if you are going to use Windows on a regular basis, I would recommend installing as much memory as your computer will accept. Early Intel based iMacs and first generation MacBook computers were limited to 2GB of memory. This is sufficient for running Windows XP in a Parallels VM, but I would not recommend running Vista unless you can allocate at least 2GB to the VM alone.

Once you have followed the setup wizard to configure your virtual machine, there are a few settings that I would recommend to improve your Parallels experience. Unless you need to load software to your Windows VM, I suggest disconnecting the CD-ROM drive for Windows. If you have enough disk space, consider creating a second hard disk image for the Windows swap file. If you need to be able to share resources between your Windows VM and other computers on the network, set your network adapter to Bridged Ethernet.

Parallels includes a feature that allows for “snapshots” to be taken of the Windows VM, which can be then be used as recovery points in the event of a problem with Windows. I do not use this feature, as the compressor can not be run if there are any existing snapshots. Instead, I shut down my Windows VM on a weekly basis, and use OS X Time Machine to archive my Parallels VM in its entirety. This allows for easier recovery in the event of a catastrophic failure, without disabling my ability to keep the performance of my VM optimized by using Parallels Compressor.

If you are running Parallels on a MacBook or MacBook Pro, I recommend suspending your Parallels session before you allow your laptop to enter sleep mode. Over the past two years, I have observed various issues with Parallels when resuming from sleep. The issues have varied from frozen applications in Windows, to video corruption to OS X locking, requiring restart. Because there can be so many variables that can affect software behavior, I find it simpler to suspend my Parallels session when I know I won’t be using it again for awhile.

There have been many upgrades to Parallels in the form of new builds, as well as updates to OS X as well. Currently, I am running Parallels 3.0 build 6508 on OS X 10.5.4 on a MacBook Pro. This seems to be very stable, considering I had some strange video issues under OS X 10.5.3. When updating to new versions of OS X, I suggest checking the Parallels Forums to be sure there are no compatibility issues before running the updates. When updating to new versions of Parallels, I suggest uninstalling the Parallels Tools and shutting down the VM before running the upgrade. I have observed severe performance issues with the VM when I allowed Parallels to upgrade Parallels Tools. A clean install after the Parallels upgrade always seems to yield the best results.