Two weeks ago I blogged about desktop virtualization and said how it worked best when it used concepts from the mainframe – and this week I’d like to continue that theme.
Although VM/370 was first released in 1972, there had been earlier versions – CP-40/CMS and CP-67/CMS – available since 1967, which makes IBM’s VM operating system, or to give it its proper name – hypervisor – pretty old. 1980 saw the release of VM/SP, 1988 saw VM/ESA, and 2000 saw z/VM – the current version. What made VM so clever and so useful to customers was the fact that it allowed other operating systems to run under it as if they were running natively (ie straight on the hardware). So rather than running one copy of MVS on one lot of hardware, it was possible to run two or three (or whatever) copies of MVS, which all appeared to be running natively on one lot of hardware.
Which means that much of the virtualization technology available on servers and the desktop is pretty much equivalent to mainframe technology in 1972 or thereabouts! It doesn’t seem quite so clever any more, does it?
IBM, of course, moved the concept of virtualization forward by including the hypervisor code with the hardware. It produced the Processor Resource/System Manager or PR/SM as it was known. The IBM Web site defines PR/SM as a type 1 hypervisor integrated with all IBM® System z™ models that transforms physical resources into virtual resources so that many logical partitions can share the same physical resources. Effectively, the VM operating system is now included in microcode in the hardware, which means that the hardware can be split into partitions and each partition can run an operating system. So users no longer need to use VM itself to virtualize their hardware, it’s built in to the hardware.
Can servers do that? The answer is yes and no – or really no, but there are some early attempts at a yes! An organization can now buy a server with an embedded hypervisor sitting on a memory card. When the server is first booted up, a menu-driven configuration process starts that results in the hypervisor being loaded and ready to accept guest operating systems. I guess that moves the timeline for off-mainframe virtualization up to about 1986!
And while we’re talking about virtualization, you may have noticed that Sun Microsystems has announced a Version 2.0 of Sun xVM VirtualBox, its free open source desktop virtualization software. And for people who aren’t sure they really know how to get the best out of the software or what to do when they hit a problem, Sun also announced Sun xVM VirtualBox Software Enterprise Subscription, which offer 24x7 support at a price.
Sun xVM VirtualBox supports Windows (including Vista), Linux (including 64-bit versions), Mac OSX, Solaris, and OpenSolaris. Sun claims that virtual desktops are the future of business desktops because they are more flexible, manageable, and secure than traditional PC architectures. It also claims that the xVM VirtualBox platform provides organizations with an easier way to deliver a standard operating environment across their enterprises. The xVM VirtualBox software runs to 20MB for those of you thinking about downloading it. There’s more information on the Sun Web site at www.sun.com/xvm.
It won't be long until the world of desktops and servers enters the 1990s – as defined by mainframes.