After conquering the desktop virtualisation space on the Mac, Parallels has decided to take the fight to VMware with a client for Windows and Linux desktops. But unlike the bi-polar world of the Mac (with Parallels and VMware being the only options), Parallels faces a multi-pronged attack on Linux, from proprietary brethren like VMware's Workstation, and free-to-download options such as Sun's VirtualBox.
So, what does Parallels Desktop 4 for Linux (let's just call it PD4) have over the competition? Here's the low down...
With PD4 you can run 32-bit and 64-bit guests and allocate more than one CPU to a virtual machine, for a total of 8. To this VM you can attach 16 virtual NICs, 8GB of virtual memory, and virtual disks worth 2 terabytes.
This is comparable to the virtual hardware you can generate with both Workstation and VirtualBox. Unfortunately, PD4 too skips the last bastion of VM connectivity -- there's no support for connecting FireWire devices. To add to its disadvantage, it also lacks any 3D capability which is now pretty much standard (albeit in beta form only) with the competition.
If you think they couldn't have blown it any further, here's another hardware gotcha. PD4 supports Intel VT-x and AMD-V hardware virtualisation technologies. But unlike Workstation and VirtualBox, PD4 wouldn't run without these extensions. Although processors with these extensions aren't expensive, insisting on them locks out a huge mass that didn't read the fine print when upgrading to dual-core processors.
Too much drag?
Despite its hardware woes, there's a good side to PD4 too. It bundles a collection of apps to assist in creating VMs and their everyday management.
Parallels Transporter is one such tool and it's designed to migrate a physical installation into a VM. If that isn't impressive enough for you, it'll work its magic on installation across the network. You can also use the tool to port VMs (including their virtual disks) created with other apps such as Workstation into PD4.
Then there's the Image Tool using which you can resize virtual disks with a nice GUI, and also change other disk properties and parameters such as its type and format. You can streamline your disks with Parallels Compressor which will defrag and then squeeze them by trimming off the free space. This is a wonderful feature for locking VMs that wouldn't grow beyond a certain size such as those running a legacy app.
Parallels steps out of Mac and falls flat on its face in Linux.
Yet Parallels has botched it. Two of these tools work exclusively on Windows guests only. The Transporter only imports Windows guests, and the Compressor works only with VMs running Windows.
There are other Windows-only features as well. With Express Install you can specify your Windows license key in advance for an uninterrupted install. You'll also find this feature in Workstation and Win4Lin.
Then there's the guest application coherence feature which lets you pull apps from within the Windows guest on to the host. This again is available on Workstation, VirtualBox (both can pull apps from either Windows and Linux guests) and Win4Lin.
If you ignore the fact that PD4 can run Linux guests (easily done since there are no major Linux-specific advantages to write home about) PD4 looks appealing to the niche that only runs Windows guests inside Linux, and should be compared to Win4Lin instead of other full-blown Linux desktop virtualisation products.
Our verdict: Doesn't set the world of desktop virtualisation on fire. Suitable for running Windows guests. 6/10
Features at a glance
Blessing and bane: Virtualisation extensions in processors are a prerequisite which PD4 exploits for speed.
Integrated tools: The bundled tools make managing VMs a charm.
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