Re: Re[3]: Tech is the biggest problem facing archiving • The Register

On 8 April 2013 08:39, Dave <dave.g4ugm at gmail.com> wrote: I am not sure they "prohibit" it, but Hyper-V uses the CPU's hardware virtualisation features. It does not and cannot do software virtualisation. VMware and VirtualBox can do S/W virtualisation, so in principle, you can run one copy under another, stacked arbitrarily deep - as deep as performance allows, anyway. VMware /invented/ S/W virtualisation of x86, thus "breaking" the Popek & Goldberg requirements. It ran x86 ring 0 code through a parser, and if it did "unclean" activity that would violate virtual machine integrity, it ran the code in a software emulator, just like SimH or Charon-VAX does. Slow, but effective, and as the CEO of Connectix (the original creators of VirtualPC) told me personally, "you'll find that, when emulating x86 on x86, the ISAs are a really remarkably good match - so the emulation speed is pretty good." ;?) -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884