An Overview of Virtualization

IndioMan writes to point us to an overview of virtualization — its history, an analysis of the techniques used over the years, and a survey of Linux virtualization projects. From the article: "Virtualization is the new big thing, if 'new' can include something over four decades old. It has been used historically in a number of contexts, but a primary focus now is in the virtualization of servers and operating systems. Much like Linux, virtualization provides many options for performance, portability, and flexibility."

Comments

Apple

[99BottlesOfBeerInMyF]

This article is an okay overview of many of ways virtualization is now being used. As an aside, has anyone else noticed Apple seems to be missing the boat this time? They're certainly benefitting from virtualization with several players in the market providing emulation solutions and tools now that they are on Intel, but Apple themselves seem to have done nothing and not even provided a strategy. Servers are moving to more virtual servers on one real machine, but OS X's license forbids it from fulfilling that role. Tools for using OS X as a thin client for accessing remote virtual machines are likewise weak. Apple hasn't even provided a virtual machine for their customers to emulate old macs so that users can run OS 9 apps on the new intel machines and they restrict redistribution of their ROM files to make 3rd parties unable to do this. No mention of adding VM technology to OS X has been heard, despite its inclusion in the Linux kernel among others.

Does Apple have something against VM technology? Are they simply behind the times and failing to see the potential?

Re:Apple

[99BottlesOfBeerInMyF]

Virtualization is usless in a desktop multimedia user environment. Video cards, sound cards and the like are bus mastering devices and you cannot virtualize hardware access unless you own the whole environment. In simple terms, virtualization is only usefull in the server arena and useless on the desktop.

As someone with two VMs running on my OS X laptop right now, I'd have to disagree with you. As for sound cards and video cards the sound works just fine and at least two companies I know of are working on support for allowing hosted OS's full access to video card acceleration.

Re:*Another* Layer?

[QuantumRiff]

For us, the nicest thing about virtualization is the disaster recovery. If our building burns down, we can quite literally get any PC we can find with a ton of RAM, load Virtual Server, and load the hosts right back up. Much, much faster than going and configuring all the weird drivers and raid cards, partitions, etc on a normal non-virtualized system. On the same note, if one of my servers goes down, I can quickly load up the VM on another box, which means I can take all the time in the world to get the original server back up, so I don't have to worry about the really expensive "4-hour" support plans, but the much cheaper "next-day" support plans. I also keep a VM copy of our web server handy. (Web server isn't on a VM, yet, because of the speed issues), so that when I need to take down the real, faster, web server, I change one DNS setting, and all my users notice is that the web is running a little slower...