On Fri, Sep 19, 2003 at 10:53:45PM +0100, Albert Schwar wrote:
> They have nothing common.
> With VM you get virtual machines.
> With VMware you get an emulator which is very restricted.
As far as I understand VMWare, it is not an emulator, actually, but a type of
hypervisor that uses many dirty tricks to provide a virtual PC on top of a
host PC. That's why it runs close to the host processor's speed for most basic
execution. It's when privileges instructions need to be executed that it gets
hit (the x86 architecture doesn't make virtualization easy). So in that sense
it has similarities to z/VM.
I think that the main (big) differences mainly result from the fact that z/VM
can depend on real hardware/microcode) support for virtualization, whereas
VMWare has to play dirty tricks. In addition to this, z/VM provides its
services as an OS on top of the hardware, whereas VMWare runs as an application
on an underlying OS (as far as I have been able to determine, even the ESX
version does this, with a minimal Linux underneath VMWare itself).
Kris
--
Never underestimate a Mage with:
- the Intelligence to cast Magic Missile,
- the Constitution to survive the first hit, and
- the Dexterity to run fast enough to avoid being hit a second time.
