When I was younger and worked on mainframes I was
always working with pretty mundane stuff; batch processing for the
most part with what little online work being done with smaller
computers (Buker-Ramo if you must know) with the mainframes running
DOS/VSE. It was hardly the big league and I lusted after the really
exotic stuff like MVS/TSO and the top of the heap; VM or Virtual
VM was a "hypervisor". That is
it wasn't really an operating system but an environment whereby
multiple operating systems could run on a single machine, each with
protected access to the full instruction set and, most importantly,
protected from each other. You could crash and burn your private
virtual machine and everything else kept on running without a hitch.
I can't recall the number of batch jobs I killed because a
problem with a program in one partition in DOS/VSE caused the whole
machine to crash.
I say "was a hypervisor". Firstly it was an OS in
it's own right and thus is more than a hypervisor and secondly it's
still around to the point that it'll run Linux as a client operating
system. But my experience was from afar, I left the mainframe world
and never got to work with it full time.
But now I have my own little virtual world. A
while back Microsoft bought Connectix and their virtual machine
technology. Oh, I'd tried it along with VMWare a while back and
frankly it didn't do much for me either because my hardware wasn't
up to it, the software wasn't robust or a combination of both but recently I picked up the
latest version of Virtual PC from Microsoft and wow, how the worm has turned,
Virtual PC 2004 has come into it's own.
What does it do? Firstly it installs in Windows XP
Pro or Win 2k Pro just like any other program. Once set up you're
ready to create as many virtual machines as you can find.
A wizard is available to walk you through the set
up but it's hardly needed. You set up the amount of RAM and hard
drive space you want to allocate to the "guest" operating system and
start preparing the virtual machine like you would a regular
computer. This might mean partitioning the hard drive, formatting it
and then installing the operating system.
What operating system? Doesn't seem to matter. It
took more time to track down old floppies than it did for me to
install Windows 2003 server, FreeDOS, BSD and DOS 7.0.
Fire up Virtual PC and a console comes up that
allows you to select an existing guest operating system or install a
Click to enlarge
What you're seeing is a regular old XP Pro desktop
with Virtual PC running Windows Server 2003 (running Internet
Explorer) in the lowest position, a DOS VM running Windows 3.1
playing solitaire in the top right position and in the top left is the Virtual PC program console.
Want a larger playground? No problem, you can enlarge any virtual
machine to full size.
So what? Well it's pretty cool to be able to
isolate various operating systems so you can do just about anything
yet not have your main machine crash and burn. You can set up a
virtual machine just like it's a real computer with it's own IP
address, installed programs, anything you can thing of.
Want to try and trash your little virtual machine?
By all means do so with no worries, you are isolated from the host
operating system and won't bother it. In fact you're so isolated
your virtual machine will need to have all patches, anti-virus
software, etc. installed just like it was a new standalone machine.
Other than the obvious benefits to developers
there's also the legacy aspect of all that great (okay, maybe not so
great) DOS software that's still out there. If you've ever wanted to
experiment or, if you're a refuge from the old days, experience some
of the old stuff again without trashing your current system Virtual
PC is the way to do it.
Performance on a perky AMD 4200+ system was brisk.
Oh, Windows Server 2003 wasn't as fast as it would have been had it
been the only thing running but it was certainly acceptable.
Everything else was certainly faster than any hardware I'd used it
on before, certainly far, far faster than say an 80286 so it seemed
remarkable quick. I did have one session in Win 2003 where I dropped
a few characters from the keyboard and from time to time I'd have to
tell DOS that there was indeed a floppy in the drive two times (a
pain when installing the 8 disk Windows for Workgroups update to Win
3.1) but nothing terminal.
There are troublesome questions; will the police
break down your door if you set up a virtual copy of XP Pro using
the same copy of XP Pro that's hosting Virtual PC? Read your EULA but Microsoft has announced that they will allow "virtulizing"
Windows Server 2003 R2 Enterprise and the Datacenter edition of
"Longhorn". Sadly they haven't made any changes to the desktop software
license that would allow virtualization.
But there's still plenty of stuff to plink away at
and you can try Virtual PC for 45 days for free. List price from Mr.
Softie is $129*. I've seen it discounted at several places and, as
always, be sure to check around for the best price. Meanwhile if you want
to check it out you can download the trial version off the Microsoft info page
*Since writing this article my opinion of
Virtual PC hasn't changed and I continue to use it daily. One new
development is that Microsoft is now giving away Virtual PC for
free. It can still be obtained at the link above.
And my biggest problem? Finding a 5.25" diskette
drive for all that old software....