Feeds

Virtualisation for Beginners

It's not just for server jockeys, you know

  • alert
  • submit to reddit

New hybrid storage solutions

Today, products like VirtualBox, Parallels Desktop and VMWare will make use of these hardware features if they're available, but still perform well on processors without them.

Parallels, for example, uses these new Intel and AMD hardware virtualisation extensions because they are almost always available on modern hardware, especially on the Mac. But Parallels can also deliver full functionality without Pacifica or Vanderpool by running in 'software mode', using techniques similar to VMWare's segment faulting

Virtualisation for Beginners

A VM is a useful testing ground for a new operating system -- in this case Google's ChromeOS under VMWare

It's tempting to think that on a multicore processor, virtualisation might allocate different cores to each of the running operating systems, but this isn't how it works. Cores are shared in much the same way as in a uniprocessor system, although the virtualiser will typically allow the user to set up 'core affinity', which associates a particular virtual machine with one or more specific cores.

But What Can I Do With It?

The most obvious use for virtualisation is running legacy apps which are perhaps no longer supported on current versions of the operating system. A tried and trusted old DOS accounting system, for example, might be carried over to Linux inside a VirtualBox virtual machine running a readily available open source version of DOS like FreeDOS.

A valuable side effect is that the application will be running in an environment isolated from other applications on the same machine, and so will probably behave more reliably than in its original habitat. And whereas in the past a failure of the application and/or the DOS environment might entail a complete reinstallation of one or both of these, now DOS and the app it's hosting can simply be reinstated as a whole, should the need arise, by restoring a snapshot of the virtual machine.

When you 'revert to snapshot' like this you'll discover immediately - or preferably have had the nous to realise well in advance - that any data used or created in connection with the application should be stored outside the virtual machine. It's usually easy enough to set up the virtual machine so that drive D: (for instance) is actually mapped to a data directory owned by the host operating system, or off on a network drive somewhere. This ensures that your set of up-to-date data hasn't been discarded with the now overwritten old version of the virtual machine.

Security for virtualized datacentres

More from The Register

next story
Not appy with your Chromebook? Well now it can run Android apps
Google offers beta of tricky OS-inside-OS tech
New 'Cosmos' browser surfs the net by TXT alone
No data plan? No WiFi? No worries ... except sluggish download speed
Greater dev access to iOS 8 will put us AT RISK from HACKERS
Knocking holes in Apple's walled garden could backfire, says securo-chap
NHS grows a NoSQL backbone and rips out its Oracle Spine
Open source? In the government? Ha ha! What, wait ...?
Google extends app refund window to two hours
You now have 120 minutes to finish that game instead of 15
Intel: Hey, enterprises, drop everything and DO HADOOP
Big Data analytics projected to run on more servers than any other app
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.