Wirt writes:
> There is reportedly a new worm coming, and according to all indications,
> this one is a great deal more dangerous than most.

> [...]if it succeeds, its success will require a system reload in order
> to get the PC back up.

Or you could simply roll back the universe to a point before you opened the
virus message :-)

I've been playing with something called VMware (www.vmware.com) which allows
you to run multiple PC operating systems in a "virtualized" environment on
your PC.

With VMware, my workstation which natively runs Windows 2000 is
simultaneously running Windows 98 and RedHat Linux 7, each in its own 64MB
memory partition and with its own virtual disk storage.  I can bring up
either of the "guest" operating systems into "full screen" mode (and hotkey
between them), at which point you can't tell that it isn't the only OS on
the system.  Each "machine" has its own IP Address, etc.

The virtual machines share the lan card, floppy disk, and CD-ROM drive with
the native system OS, and VMware provide drivers and tools for Linux and
Windows that allow these guest OSes to use the full screen resolution and
color depth of the host OS.  So I can pop back and forth between Windows 98,
2000, and Linux (running the Gnome desktop) all at 1280x1024x32bit color.

The virtual machines are totally isolated from the native host OS, and thus
can be used to try out "dangerous" software without endangering the "real"
system.  So for example, I could easily install a second instance of Windows
2000 and install Outlook into it and have a virtual machine dedicated to
doing nothing but reading email.  Should a virus ever get loose, it would be
unable to directly access anything important on the machine.

And perhaps the coolest feature of VMware is the ability to configure
"virtual" IDE disks (up to 2GB each) as "undoable" or "read only" such that
while the guest OS is running, it *thinks* it's writing all over the disk,
but in fact VMware is directing all writes to a temporary "shadow" file and
when you shut down the virtual machine you can choose whether or not to
commit those disk writes, so that if you choose you can make the entire
session have never happened.

So if you read your email in an OS running in a virtual machine so
configured, and if a virus gets loose and trashes the machine completely,
you can just quit that virtual machine and tell VMware to "undo" everything
that happened since that VM was last started, thus rolling back one of your
private little universes to a point in time before the bad things started to
happen.  Don't you sometimes wish you could do this in real life?

VMware requires either Linux or Windows NT/2000 as the host OS, and in
either case will run DOS, Windows 3.1, Windows 95, 98, ME, NT, and 2000,
most versions of Linux, FreeBSD, and other x86 based operating systems as
"guest" OSes inside virtual machines.

Performance is quite good with Windows 98 and Linux from my experience so
far, and when these guest OSes are idle, the host CPU is idle as well, so
you can run multiple OSes at once without damaging the performance of things
running in the native host OS.

You probably want a reasonably fast CPU of course, and you'll need lots of
memory (a 64MB virtual machine seems to want about 80MB of real RAM) and a
reasonably large hard disk to hold your virtual disk images (though VMware
seems to only use physical disk space that is actually allocated in the
virtual disk, at least with some file system formats).

The full VMware product costs $299, but there is also a $79 version for
Linux that will let you run one instance of Windows 95 or Windows 98 if you
just want a cheap way to get Windows functionality under Linux.  You can
download a free 30 day demo of the full product from their web site.

I started out thinking that $300 was rather a lot of money, but I've been
really impressed at how well this thing works, and that's starting to look
like a lot less money than it did at the outset.

Mac users have a similar product available called VirtualPC which does
pretty much the same things (and it's considerably cheaper too!)

If you think about it, this kind of VM technology (pioneered by IBM
mainframes and others) is the same thing that makes HP's Superdome an
attractive platform for consolidation.  Once you have the ability to create
and duplicate whole PCs at will, all sorts of things become possible.
Probably the person who can best take advantage of VMware is a PC developer
who needs to test their software under multiple OS versions and for whom
being able to run them all at the same time (safely too) on one box is quite
powerful.  If I want to try out something new, I can either use the ability
to "undo" a session if I don't like the results, or I can just go to the
native OS and duplicate one of my virtual machine's virtual disk files and
boot up a copy of it.  And all of this goes on without disturbing the
underlying OS, so I can reboot my "test" machine every hour if I have to
without needing to shutdown and restart everything else that I have running.
Very cool.

G.