First of all, I had a problem with your definition of 'emulation' versus virtualization. If you create a complete virtual machine in software, then it is a simulation. An emulation is when the hardware emulates the other machine. These definitions come from the 60s and 70s: my first job was supporting and enhancing a 1401/1108 simulator, a very large and complex piece of software that enabled IBM 1400 programs to be executed in a simulated environment on a Univac 1100-series mainframe computer. At the same time, IBM offered '1400 Emulation Mode' on the S/360, whereby you flicked a switch and the whole 360 bedame capable of executing 1400 programs.
Neither of these processes are considered virtualization - that was the province of VM/370, a slick piece of software that enabled an IBM mainframe to run several different OS in partitions at the same time - and I believe it is still around.
The second nit-pick was your description of MojoPac, which totally failed to explain what it was to any extent that I could grasp. (I don't think I'll be alone in this!) I got the bit about installing and running it from a USB drive, but how an iPod can be used as a portable desktop was beyond my reach.
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Re: A couple bones to pick on virtualization
Regarding “simulate” and “emulate”: If you look up the words you will find they are synonymous (http://dictionary.reference.com/browse/simulate and http://dictionary.reference.com/browse/emulate -- also http://thesaurus.reference.com/browse/emulate). Even Wikipedia fails to draw a distinction in their use in computer terminology (http://en.wikipedia.org/wiki/Simulation). The fact that the term simulator was used in the 60s and 70s in the Univac world doesn’t change the dictionary definition or, for that matter, current usage (as illustrated by the Wikipedia articles).
As for my inadequate explanation of MojoPac I thought that –
MojoPac gives you, in effect, a portable Windows XP desktop using operating system virtualization to create an isolated Windows XP guest virtual machine that runs alongside the host Windows XP
-- was reasonably clear but perhaps not. Please see this week’s Gearhead (http://www.networkworld.com/columnists/2007/120407-gearhead.html) – hopefully my explanations are better this time around.
Finally on using an iPod with MojoPac: Perhaps you aren’t aware that when you plug an iPod (formatted for a PC) into a PC using USB its storage is visible just like any other USB mass storage device. As a result MojoPac can be installed on and launched from the iPod storage.
The simulation vs emulation distinction wasn't just Univac
All the vendors used it - especially IBM. I was amused by the idea that Wikipedia might be a reference for a 1970s computing environment. However, in that spirit, let me reference: IBM pioneered the use of microcode emulation, in the form of ROM and SPICE (Simulation Program ...) which clearly suggests that software makes a simulator, not an emulator. [I think the correct emoticon at this point is :-) ]
My MojoPac confusion was the perhaps mind-boggling array of USB options for launching it. Maybe you are used to applications launched from an external device - the only one I've used was the installer on my portable disk drive.
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